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Configuring ATM

Configuring ATM

This chapter describes how to configure an Asynchronous Transfer Mode (ATM) interface in the Cisco 7000 series, Cisco 7500 series, Cisco 4500, and Cisco 4700 routers, and how to configure a serial interface for ATM access in other routers.

For routers that use a serial interface for ATM access through an ATM data service unit (ADSU), the chapter explains the steps necessary to enable Asynchronous Transfer Mode-Data Exchange Interface (ATM-DXI) encapsulation, select a multiprotocol encapsulation method using ATM-DXI, and set up a permanent virtual circuit (PVC) for the selected encapsulation.

For Cisco 7000 series and Cisco 7500 series routers that have an ATM Interface Processor (AIP), the chapter explains the steps necessary to configure the AIP, PVCs, switched virtual circuits (SVCs), and Classical IP over ATM.

For Cisco 4500 and Cisco 4700 routers that have an ATM network processor module (NPM), this chapter explains the steps necessary to configure the ATM, PVCs, and SVCs.


Note ATM is currently not supported on Cisco 2500 series and Cisco AS5100 access servers.

For a complete description of the commands in this chapter, refer to the "ATM Commands" chapter in the Wide-Area Networking Command Reference.

For information about SMDS support using AIP, refer to the "SMDS Commands" chapter in the Wide-Area Networking Command Reference.

For information about configuring LAN emulation (LANE) for ATM, refer to the "Configuring LAN Emulation (LANE)" chapter of this manual. For information about LANE commands, refer to the "LAN Emulation (LANE) Commands" chapter in the Wide-Area Networking Command Reference.

ATM Access over a Serial Interface

Our routers provide ATM access in three ways, depending on the hardware available in the router:

In routers other than the Cisco 4500, Cisco 4700, Cisco 7000 series, and Cisco 7500 series, a serial interface can be configured for multiprotocol encapsulation over ATM-DXI, as specified by RFC 1483. ATM-DXI encapsulation allows a DCE and a DTE to cooperate to provide a User-Network Interface (UNI) for ATM networks. At the ADSU, the DXI header is stripped off, and the protocol data is segmented into cells for transport over the ATM network.

RFC 1483 describes two methods of transporting multiprotocol connectionless network interconnect traffic over an ATM network. One method allows multiplexing of multiple protocols over a single PVC. The other method uses different virtual circuits to carry different protocols. Our implementation of RFC 1483 supports both methods and supports transport of Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS traffic.

In routers other than the Cisco 4500, Cisco 4700, Cisco 7000 series, and Cisco 7500 series, an ADSU is required to provide the ATM interface to the network, convert outgoing packets into ATM cells, and reassemble incoming ATM cells into packets.

ATM Serial Access Configuration Task List

To configure ATM access over a serial interface on routers outside the Cisco 7000, Cisco 7500, Cisco 4500, and Cisco 4700, complete the tasks in the following sections. The first four tasks are required.

Step 1 Enable the Serial Interface

Step 2 Enable ATM-DXI Encapsulation

Step 3 Set Up the ATM-DXI PVC

Step 4 Map Protocol Addresses to the ATM-DXI PVC

Step 5 Monitor and Maintain the ATM-DXI Serial Interface

Enable the Serial Interface

To begin configuring the serial interface for ATM access, enable the serial interface by performing the following steps beginning in global configuration mode:

Task Command
Enable the serial interface. interface serial number1
For each protocol to be carried, assign a protocol address to the interface. (The commands shown are a partial list for the supported protocols.) appletalk address network.node2
ip address address mask3
ipx network number4

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "AppleTalk Commands" chapter in the Network Protocols Command Reference, Part 1.
3 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.
4 This command is documented in the "Novell IPX Commands" chapter in the Network Protocols Command Reference, Part 2.

The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.

For information about the addressing requirements of a protocol, see the relevant protocol configuration chapter in the Network Protocols Configuration Guide, Part 1, the Network Protocols Configuration Guide, Part 2, or Network Protocols Configuration Guide, Part 3.

Enable ATM-DXI Encapsulation

To enable ATM-DXI encapsulation on a serial or High-Speed Serial Interface (HSSI), perform the following task in interface configuration mode:

Task Command
Enable ATM-DXI encapsulation. encapsulation atm-dxi1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

Set Up the ATM-DXI PVC

An ATM-DXI PVC can be defined to carry one protocol, multiple protocols as described by RFC 1490, or multiple protocols as described by RFC 1483.

To set up the ATM-DXI PVC, perform the following task in interface configuration mode:

Task Command
Define the ATM-DXI PVC and the encapsulation method. dxi pvc vpi vci [snap | nlpid | mux]

The MUX (multiplex) option defines the PVC to carry one protocol only; each protocol must be carried over a different PVC. The network layer protocol identification (NLPID) option is multiprotocol encapsulation, compatible with RFC 1490; this option is provided for backward compatibility with the default setting in earlier versions in the Cisco IOS software. The SNAP (Subnetwork Access Protocol) option is LLC/SNAP multiprotocol encapsulation, compatible with RFC 1483; SNAP is the current default option.  


Note The default encapsulation was NLPID in software earlier than Release 10.3. Starting with that release, the default encapsulation is SNAP. Select the nlpid keyword now if you had previously selected the default.

Map Protocol Addresses to the ATM-DXI PVC

This section describes how to map protocol addresses to the virtual channel identifier (VCI) and the virtual path identifier (VPI) of a PVC that can carry multiprotocol traffic. The protocol addresses belong to the host at the other end of the link. To map a protocol address to an ATM-DXI PVC, complete the following task in interface configuration mode:

Task Command
Map a protocol address to the ATM-DXI PVC's VPI and VCI. dxi map protocol protocol-address vpi vci [broadcast]

Repeat this task for each protocol to be carried on the PVC.

The supported protocols are Apollo Domain, AppleTalk, Banyan VINES, DECnet, IP, Novell IPX, ISO CLNS, and XNS.

For an example of configuring a serial interface for ATM, see the "ATM Access over a Serial Interface Example" section later in this chapter.

Monitor and Maintain the ATM-DXI Serial Interface

After configuring the serial interface for ATM, you can display the status of the interface, the ATM-DXI PVC, or the ATM-DXI map. To display interface, PVC, or map information, complete the following tasks in EXEC mode:

Task Command
Display the serial ATM interface status. show interfaces atm [slot/port]1
Display the ATM-DXI PVC information. show dxi pvc
Display the ATM-DXI map information. show dxi map

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

Cisco 7000 Family Configuration Task List

To configure ATM on the AIP in Cisco 7000 series routers, complete the tasks in the following sections. The first task is required, and then you must configure at least one PVC or SVC. The virtual circuit options you configure must match in three places: on the router, on the ATM switch, and at the remote end of the PVC or SVC connection. The remaining tasks are optional.

See the "Cisco 7000 Family Configuration Examples" section for configuration examples.

Enable the AIP on the Cisco 7000 Family

This section describes how to begin configuring the AIP. The Cisco 7000 series and Cisco 7500 series identify an interface address by its slot number (slots 0 to 4) and port number in the format slot/port. Because each AIP contains a single ATM interface, the port number is always 0. For example, the slot/port address of an ATM interface on an AIP installed in slot 1 is 1/0.

To begin to configure the AIP, start the following task in privileged EXEC mode:

Task Command
Step 1 At the privileged EXEC prompt, enter configuration mode from the terminal. configure1
[terminal] <CR>
Step 2 Specify an AIP interface. interface atm slot/02
Step 3 If IP routing is enabled on the system, optionally assign a source IP address and subnet mask to the interface. ip address ip-address mask3

1 This command is documented in the "System Image and Configuration File Load Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
3 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.

To enable the AIP, perform the following task in interface configuration mode:

Task Command
Change the shutdown state to up and enable the ATM interface, thereby starting the segmentation and reassembly (SAR) operation on the interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

The no shutdown command passes an enable command to the AIP, which then begins segmentation and reassembly (SAR) operations. It also causes the AIP to configure itself based on the previous configuration commands sent.

Configure PVCs on the Cisco 7000 Family

To use a permanent virtual circuit (PVC), you must configure the PVC into both the router and the ATM switch. PVCs remain active until the circuit is removed from either configuration.

All virtual circuit characteristics listed in the section "AIP Virtual Circuits" in the "Wide-Area Networking Overview" chapter apply to these PVCs. When a PVC is configured, all the configuration options are passed on to the AIP. These PVCs are writable into the nonvolatile RAM (NVRAM) as part of the Route Processor (RP) configuration and are used when the RP image is reloaded.

Some ATM switches might have point-to-multipoint PVCs that do the equivalent of broadcasting. If a point-to-multipoint PVC exists, then that PVC can be used as the sole broadcast PVC for all multicast requests.

To configure a PVC, perform the tasks in the following sections. The first three tasks are required; the last two are optional.

Create a PVC (Cisco 7000 Family)

To create a PVC on the AIP interface, perform the following task in interface configuration mode:

Task Command
Create a PVC. atm pvc vcd vpi vci aal-encap [[midlow midhigh] [peak average burst]] [oam seconds]

When you create a PVC, you create a virtual circuit descriptor (VCD) and attach it to the VPI and VCI. A VCD is an AIP-specific mechanism that identifies to the AIP which VPI-VCI pair to use for a particular packet. The AIP requires this feature to manage the packets for transmission. The number chosen for the VCD is independent of the VPI-VCI pair used.

When you create a PVC, you also specify the ATM adaptation layer (AAL) and encapsulation. A rate queue is used that matches the peak and average rate selections, which are specified in kilobits per second. Omitting a peak and average value causes the PVC to be connected to the highest bandwidth rate queue available. In this case, the peak and average values are equal.

You can also configure the PVC for communication with the Interim Local Management Interface (ILMI) so the router can receive Simple Network Management Protocol (SNMP) traps and new network prefixes. Refer to the "Configure Communication with the ILMI (Cisco 7000 Family)" section for details.

You can also optionally configure the PVC to send Operation, Administration, and Maintenance (OAM) F5 loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells.

See examples of PVC configurations in the section "Cisco 7000 Family Configuration Examples" at the end of this chapter.

Map a Protocol Address to a PVC (Cisco 7000 Family)

The ATM interface supports a static mapping scheme that identifies the ATM address of remote hosts or routers. This address is specified as a virtual circuit descriptor (VCD) for a PVC (or an NSAP address for SVC operation). This section describes how to map a PVC to an address, which is a required task if you are configuring a PVC.

You enter mapping commands as groups. You first create a map list and then associate it with an interface. Begin the following tasks in global configuration mode:

Task Command
Step 1 Create a map list by naming it, and enter map-list configuration mode. map-list name
Step 2 Associate a protocol and address to a specific virtual circuit. protocol protocol-address atm vc vcd [broadcast]
Step 3 Associate a protocol and address to a different virtual circuit. protocol protocol-address atm vc vcd [broadcast]
Step 4 Specify an ATM interface and enter interface configuration mode. interface atm slot/port1
Step 5 Associate a map list to an interface. map-group name

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

A map list can contain multiple map entries, as Steps 2 and 3 in the preceding task table illustrate. The broadcast keyword specifies that this map entry is to be used when the corresponding protocol sends broadcast packets to the interface (for example, any network routing protocol updates). If you do not specify broadcast, the ATM software is prevented from sending routing protocol updates to the remote hosts.

If you do specify broadcast, but do not set up point-to-multipoint signaling, pseudobroadcasting is enabled. To eliminate pseudobroadcasting and set up point-to-multipoint signaling on virtual circuits configured for broadcasting, see the "Configure Point-to-Multipoint Signaling (Cisco 7000 Family)" section.

Step 5 illustrates that when the map list is complete, you associate the map list with an ATM interface by using the same name argument.

You can create multiple map lists, but only one map list can be associated with an interface. Different map lists can be associated with different interfaces. See the examples at the end of this chapter.

Configure Communication with the ILMI (Cisco 7000 Family)

You can configure a PVC for communication with the Interim Local Management Interface (ILMI) so the router can receive SNMP traps and new network prefixes. The recommended vpi/vci for ILMI is 0 16. To configure ILMI communication, complete the following task in interface configuration mode:

Task Command
Create an ILMI PVC on a major interface. atm pvc vcd vpi vci ilmi

Note This ILMI PVC can be set up only on a major interface, not on the subinterfaces.

Once you have configured an ILMI PVC, you can optionally enable the ILMI keepalive function by completing the following task in interface configuration mode:

Optionally, enable ILMI keepalives and set the interval between keepalives. atm ilmi-keepalive [seconds]

No other configuration steps are required.

ILMI address registration for receipt of SNMP traps and new network prefixes is enabled by default. The ILMI keepalive function is disabled by default; when enabled, the default interval between keepalives is 3 seconds.

Configure ATM UNI Version Override (Cisco 7000 Family)

Normally, when ILMI link autodetermination is enabled on the interface and is successful, the router takes the user-network interface (UNI) version returned by ILMI. If the ILMI link autodetermination process is unsuccessful or ILMI is disabled, the UNI version defaults to 3.0. You can override this default by using the atm uni-version command. The no form of the command sets the UNI version to the one returned by ILMI if ILMI is enabled and the link autodetermination is successful. Otherwise, the UNI version will revert to 3.0.

Task Command
Override UNI version used by router. [no] atm uni-version version number

No other configuration steps are required.

Configure Transmission of Loopback Cells to Verify Connectivity (Cisco 7000 Family)

You can optionally configure the PVC to send OAM F5 loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells. If OAM response cells are missed (indicating the lack of connectivity), the system console displays a debug message indicating the failure of the PVC, provided the debug atm errors command is enabled. If you suspect that a PVC is faulty, enabling OAM cell generation and the debug atm errors command allows you to monitor the status of the PVC.

To configure the transmission of OAM F5 loopback cells, add the oam keyword to the atm pvc command, as shown in the following task:

Task Command
Configure transmission of OAM F5 cells on the PVC. atm pvc vcd vpi vci aal-encap [[midlow midhigh] [peak average burst]] [oam seconds]

Configure SVCs on the Cisco 7000 Family

ATM switched virtual circuit (SVC) service operates much like X.25 SVC service, although ATM allows much higher throughput. Virtual circuits are created and released dynamically, providing user bandwidth on demand. This service requires a signaling protocol between the router and the switch.

The ATM signaling software provides a method of dynamically establishing, maintaining, and clearing ATM connections at the User-Network Interface (UNI). The ATM signaling software conforms to ATM Forum UNI 3.0 or ATM Forum UNI 3.1 depending on what version is selected by ILMI or configuration.

In UNI mode, the user is the router and the network is an ATM switch. This is an important distinction. The Cisco router does not perform ATM-level call routing. Instead, the ATM switch does the ATM call routing, and the router routes packets through the resulting circuit. The router is viewed as the user and the LAN interconnection device at the end of the circuit, and the ATM switch is viewed as the network.

Figure 8 illustrates the router position in a basic ATM environment. The router is used primarily to interconnect LANs via an ATM network. The workstation connected directly to the destination ATM switch illustrates that you can connect not only routers to ATM switches, but also any computer with an ATM interface that conforms to the ATM Forum UNI specification.


Figure 8: Basic ATM Environment


Complete the tasks in the following sections to use SVCs. The first two tasks are required; the third and fourth are optional:

The tasks in the following sections are optional SVC tasks for customizing your network. These tasks are considered advanced; the default values are almost always adequate. You should not have to perform these tasks unless you need to customize your particular SVC connection.

Configure the PVC That Performs SVC Call Setup (Cisco 7000 Family)

Unlike X.25 service, which uses in-band signaling (connection establishment done on the same circuit as data transfer), ATM uses out-of-band signaling. One dedicated PVC exists between the router and the ATM switch, over which all SVC call establishment and call termination requests flow. After the call is established, data transfer occurs over the SVC, from router to router. The signaling that accomplishes the call setup and teardown is called Layer 3 signaling or the Q.2931 protocol.

For out-of-band signaling, a signaling PVC must be configured before any SVCs can be set up. Figure 9 illustrates that a signaling PVC from the source router to the ATM switch is used to set up two SVCs. This is a fully meshed network; workstations A, B, and C all can communicate with each other.


Figure 9:
One or More SVCs Require a Signaling PVC


To configure the signaling PVC for all SVC connections, perform the following task in interface configuration mode:

Task Command
Configure the signaling PVC for a major interface that uses SVCs. atm pvc vcd vpi vci qsaal

Note This signaling PVC can be set up only on a major interface, not on the subinterfaces.

The VPI and VCI values must be configured consistently with the local switch. The standard value of VPI is 0; the standard value of VCI is 5.

See the section "SVCs in a Fully Meshed Network Example (Cisco 7000 Family)" at the end of this chapter for a sample ATM signaling configuration.

Configure the NSAP Address (Cisco 7000 Family)

Every ATM interface involved with signaling must be configured with an network service access point (NSAP) address. The NSAP address is the ATM address of the interface and must be unique across the network.

Complete one of the tasks in the following sections to configure an NSAP address:

If you choose to configure the end station ID (ESI) and selector fields, you also must configure a PVC to communicate with the switch via ILMI. The switch then provides the prefix field of the NSAP address.

Configure the Complete NSAP Address Manually (Cisco 7000 Family)

When you configure the ATM NSAP address manually, you must enter the entire address in hexadecimal format since each digit entered represents a hexadecimal digit. To represent the complete NSAP address, you must enter 40 hexadecimal digits in the following format:

XX.XXXX.XX.XXXXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XX

Note  All ATM NSAP addresses may be entered in the dotted hexadecimal format shown, which conforms to the UNI specification. The dotted method provides some validation that the address is a legal value. If you know your address format is correct, the dots may be omitted.

Because the interface has no default NSAP address, you must configure the NSAP address for SVCs. To set the ATM interface's source NSAP address, perform the following task in interface configuration mode:

Task Command
Configure the ATM NSAP address for an interface. atm nsap-address nsap-address

The following example assigns NSAP address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12 to ATM interface 4/0:

interface ATM4/0
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12

You can display the ATM address for the interface by executing the show interface atm command.

Configure the ESI and Selector Fields

To use this method of entering the router's NSAP address, the switch must be capable of delivering the NSAP address prefix to the router via ILMI and the router must be configured with a PVC for communication with the switch via ILMI.

To configure the router to get the NSAP prefix from the switch and use locally entered values for the remaining fields of the address, complete the following tasks in interface configuration mode:

Task Command
Step 1 Configure a PVC for communicating with the switch via ILMI. atm pvc vcd 0 16 ilmi
Step 2 Enter the ESI and selector fields of the NSAP address. atm esi-address esi.selector

In the atm esi-address command, the esi argument is 6 hexadecimal bytes long (12 digits), and the selector argument is one hexadecimal byte long (2 digits).

You can also specify a keepalive interval for the ILMI PVC. See the "Configure Communication with the ILMI (Cisco 7000 Family)" section for more information.

The following example on a Cisco 7000 router assigns the ESI and selector field values and sets up the ILMI PVC:

interface atm 4/0
atm pvc 2 0 16 ilmi
atm esi-address 345678901234.12

Configure the Idle Timeout Interval (Cisco 7000 Family)

You can specify an interval of inactivity after which any idle SVC on an interface will be disconnected. This timeout interval might help control costs and free router memory and other resources for other uses.

To change the idle timeout interval, perform the following task in interface configuration mode:

Task Command
Configure the interval of inactivity after which an idle SVC will be disconnected. atm idle-timeout seconds

The default idle timeout interval is 300 seconds (5 minutes).

Configure Point-to-Multipoint Signaling (Cisco 7000 Family)

Point-to-multipoint signaling (or multicasting) allows the router to send one packet to the ATM switch and have the switch replicate the packet to the destinations. It replaces pseudobroadcasting on specified virtual circuits for protocols configured for broadcasting.

You configure multipoint signaling on an ATM interface after you have mapped protocol addresses to NSAPs and configured one or more protocols for broadcasting.

After multipoint signaling is set, the router uses existing static map entries that have the broadcast keyword set to establish multipoint calls. The call is established to the first destination with a Setup message. Additional parties are added to the call with AddParty messages each time a multicast packet is sent. One multipoint call will be established for each logical subnet of each protocol that has the broadcast keyword set.

To configure multipoint signaling on an ATM interface, complete the following tasks beginning in global configuration mode. The first task is required to configure this feature; the others are optional.

Task Command
Step 1 Specify the ATM interface. interface atm slot/port1
Step 2 Provide a protocol address for the interface. protocol protocol-address mask
Step 3 Associate a map list to the interface. map-group name
Step 4 Provide an ATM NSAP address for the interface. atm nsap-address nsap-address
Step 5 Configure the signaling PVC for the interface that uses SVCs. atm pvc vcd vpi vci qsaal
Step 6 Associate a map list with the map group. map-list name
Step 7 Configure a broadcast protocol for the remote NSAP address on the SVC.

Repeat this step for other NSAP addresses, as needed.

protocol protocol-address atm-nsap atm-nsap-address broadcast
Step 8 Enable multipoint signaling to the ATM switch. atm multipoint-signaling
Step 9 Limit the frequency of sending AddParty messages (optional). atm multipoint-interval interval

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

If multipoint virtual circuits are closed, they are reopened with the next multicast packet. Once the call is established, additional parties are added to the call when additional multicast packets are sent. If a destination never comes up, the router constantly attempts to add it to the call by means of multipoint signaling.

For an example of configuring multipoint signaling on an interface that is configured for SVCs, see the "SVCs with Multipoint Signaling Example (Cisco 7000 Family)" later in this chapter.

Change Traffic Values (Cisco 7000 Family)

The tasks in this section are optional and advanced. The ATM signaling software can specify to the AIP card and the ATM switch a limit on how much traffic the source router will be sending. It provides this information in the form of traffic parameters. (These parameters have default values.) The ATM switch in turn sends these parameters as requested by the source to the ATM destination node. If the destination cannot provide such capacity levels, the call may fail (for Cisco 7000 family behavior, see the per-interface atm sig-traffic-shaping strict command in the Wide-Area Networking Command Reference). There is a single attempt to match traffic parameters.

This section describes how to change traffic values to customize your SVC connection. The individual tasks that separately specify peak, sustainable, or burst values for an SVC are analogous to the peak, average, and burst values defined when you create a PVC. Valid values for the peak rate on the AIP are between 130 kbps and the PLIM rate. The valid values for the average rate are fractions of the peak rate--the peak rate divided by a number between 1 and 64. When the average rate is below one-half the peak rate, the average rate defaults to the next available fraction. The valid range for the maximum burst size is between 32 cells and 2016 cells. Values between 32 and 2016 will round up to the next multiple of 32 cells.

Forward commands apply to the flow of cells from the source router to the destination router. Backward commands apply to the flow of cells from the destination router to the source router.

Most of the SVC traffic parameters include the concept of cell loss priority (CLP). CLP defines two levels of cell importance:

Figure 10 illustrates a source and destination router implementing traffic settings that correspond end-to-end. The value for the forward command at the source router corresponds to the value for the backward command at the destination router.


Figure 10: Source and Destination Routers Have Corresponding Traffic Settings


You can define map lists and map groups to tie specified SVCs to the protocol addresses of remote hosts and to specify whether broadcast protocols are supported. Then you can define map classes and specify the traffic parameters needed for the specified protocol traffic on those SVCs.

You must enter map-class configuration mode before you can change the traffic values from their default values. To enter map-class configuration mode, perform the following task in global configuration mode:

Task Command
Enter map-class configuration mode, specifying a map-class name. map-class atm class-name

If a map class with the specified name does not exist, the router creates a new one. All the following commands apply to the named map class.

See the "Traffic Parameters Example (Cisco 7000 Family)" section for an example defining map classes, map groups, map lists and traffic parameters.

To change traffic parameters, perform one or more of the following tasks in map-class configuration mode:

Task Command
Set the source-to-destination peak cell rate for high-priority cells. atm forward-peak-cell-rate-clp0 rate
Set the destination-to-source peak cell rate for high-priority cells. atm backward-peak-cell-rate-clp0 rate
Set the source-to-destination peak cell rate for the aggregate of low-priority and high-priority cells. atm forward-peak-cell-rate-clp1 rate
Set the destination-to-source peak cell rate for the aggregate of low-priority and high-priority cells. atm backward-peak-cell-rate-clp1 rate
Set the source-to-destination sustainable cell rate for high-priority cells. atm forward-sustainable-cell-rate-clp0 rate
Set the destination-to-source sustainable cell rate for high-priority cells. atm backward-sustainable-cell-rate-clp0 rate
Set the source-to-destination sustainable cell rate for the aggregate of low-priority and high-priority cells. atm forward-sustainable-cell-rate-clp1 rate
Set the destination-to-source sustainable cell rate for the aggregate of low-priority and high-priority cells. atm backward-sustainable-cell-rate-clp1 rate
Set the source-to-destination burst size for high-priority cells. atm forward-max-burst-size-clp0 cell-count
Set the destination-to-source burst size for high-priority cells. atm backward-max-burst-size-clp0 cell-count
Set the source-to-destination burst size for the aggregate of low-priority and high-priority cells. atm forward-max-burst-size-clp1 cell-count
Set the destination-to-source burst size for the aggregate of low-priority and high-priority cells. atm backward-max-burst-size-clp1 cell-count

Configure SSCOP (Cisco 7000 Family)

The Service-Specific Connection-Oriented Protocol (SSCOP) resides in the service-specific convergence sublayer (SSCS) of the ATM adaptation layer (AAL). SSCOP is used to transfer variable-length service data units (SDUs) between users of SSCOP. SSCOP provides for the recovery of lost or corrupted SDUs.


Note The tasks in this section customize the SSCOP feature to a particular network or environment and are optional. The features have default values and are valid in most installations. Before customizing these features, you should have a good understanding of SSCOP and the network involved.

Set the Poll Timer (Cisco 7000 Family)

The poll timer controls the maximum time between transmission of a POLL PDU when sequential data (SD) or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the poll timer from the default value of 10 seconds, perform the following task in interface configuration mode:

Task Command
Set the poll timer. sscop poll-timer seconds

Set the Keepalive Timer (Cisco 7000 Family)

The keepalive timer controls the maximum time between transmission of a POLL PDU when no SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the keepalive timer from the default value of 30 seconds, perform the following task in interface configuration mode:

Task Command
Set the keepalive timer. sscop keepalive-timer seconds

Set the Connection Control Timer (Cisco 7000 Family)

The connection control timer determines the time between transmission of BGN, END, or RS (resynchronization) PDUs as long as an acknowledgment has not been received. Connection control performs the establishment, release, and resynchronization of an SSCOP connection.

To change the connection control timer from the default value of 10 seconds, perform the following task in interface configuration mode:

Task Command
Set the connection control timer. sscop cc-timer seconds

To change the retry count of the connection control timer from the default value of 10, perform the following task in interface configuration mode:

Task Command
Set the number of times that SSCOP will retry to transmit BGN, END, or RS PDUs when they have not been acknowledged. sscop max-cc retries

Set the Transmitter and Receiver Windows (Cisco 7000 Family)

A transmitter window controls how many packets can be transmitted before an acknowledgment is required. To change the transmitter's window from the default value of 7, perform the following task in interface configuration mode:

Task Command
Set the transmitter's window. sscop send-window packets

A receiver window controls how many packets can be received before an acknowledgment is required. To change the receiver's window from the default value of 7, perform the following task in interface configuration mode:

Task Command
Set the receiver's window. sscop rcv-window packets

Close an SVC (Cisco 7000 Family)

You can disconnect an idle SVC by completing the following task in EXEC mode:

Task Command
Close the signaling PVC for an SVC. atmsig close atm slot/0 vcd

Configure Classical IP and ARP over ATM on the Cisco 7000 Family

Cisco implements both the ATM Address Resolution Protocol (ARP) server and ATM ARP client functions described in RFC 1577. RFC 1577 models an ATM network as a logical IP subnetwork on a LAN.

The tasks required to configure classical IP and ARP over ATM depend on whether the environment uses SVCs or PVCs.

Configure Classical IP and ARP in an SVC Environment (Cisco 7000 Family)

The ATM ARP mechanism is applicable to networks that use SVCs. It requires a network administrator to configure only the device's own ATM address and that of a single ATM ARP server into each client device. When the client makes a connection to the ATM ARP server, the server sends ATM Inverse ARP requests to learn the IP network address and ATM address of the client on the network. It uses the addresses to resolve future ATM ARP requests from clients. Static configuration of the server is not required or needed. 

In Cisco's implementation, the ATM ARP client tries to maintain a connection to the ATM ARP server. The ATM ARP server can tear down the connection, but the client attempts once each minute to bring the connection back up. No error messages are generated for a failed connection, but the client will not route packets until the ATM ARP server is connected and translates IP network addresses.

For each packet with an unknown IP address, the client sends an ATM ARP request to the server. Until that address is resolved, any IP packet routed to the ATM interface will cause the client to send another ATM ARP request. When the ARP server responds, the client opens a connection to the new destination so that any additional packets can be routed to it.

Cisco routers may be configured as ATM ARP clients to work with any ATM ARP server conforming to RFC 1577. Alternatively, one of the Cisco routers in a logical IP subnet (LIS) may be configured to act as the ATM ARP server itself. In this case, it automatically acts as a client as well. To configure classical IP and ARP in an SVC environment, perform one of the following tasks:

Configure as an ATM ARP Client (Cisco 7000 Family)

In an SVC environment, configure the ATM ARP mechanism on the interface by performing the following tasks in interface configuration mode: 

Task Command
Step 1 Specify an AIP interface. interface atm slot/01
Step 2 Specify the ATM address of the interface. atm nsap-address nsap-address
Step 3 Specify the IP address of the interface. ip address address mask2
Step 4 Specify the ATM address of the ATM ARP server. atm arp-server nsap nsap-address
Step 5 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Commands Reference, Part 1.

You can designate the current router interface as the ATM ARP server in Step 4 by typing self instead the NSAP address. For an example of configuring the ATM ARP client, see the "ATM ARP Client Configuration in an SVC Environment Example (Cisco 7000 Family)" section later in this chapter.

Configure as an ATM ARP Server (Cisco 7000 Family)

Cisco's implementation of the ATM ARP server supports a single, nonredundant server per logical IP subnetwork (LIS) and supports one ATM ARP server per subinterface. Thus, a single AIP card can support multiple ARP servers by using multiple subinterfaces.

To configure the ATM ARP server, complete the following tasks in interface configuration mode:

Task Command
Step 1 Specify an AIP interface. interface atm slot/01
Step 2 Specify the ATM address of the interface. atm arp-server nsap nsap-address
Step 3 Specify the IP address of the interface. ip address address mask2
Step 4 Identify the ATM ARP server for the IP subnetwork network and set the idle timer. atm arp-server time-out minutes3
Step 5 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Commands Reference, Part 1.
3 When you use this form of the atm arp-server command, it indicates that this interface will perform the ATM ARP server functions. When you configure the ATM ARP client (as described earlier), the atm arp-server command is used--with a different keyword and argument--to identify a different ATM ARP server to the client.

You can designate the current router interface as the ATM ARP server in Step 2 by typing self instead of the NSAP address.

The idle timer interval is the number of minutes a destination entry listed in the ATM ARP server's ARP table can be idle before the server takes any action to time out the entry.

For an example of configuring the ATM ARP server, see the "ATM ARP Server Configuration in an SVC Environment Example (Cisco 7000 Family)" section later in this chapter.

Configure Classical IP and Inverse ARP in a PVC Environment (Cisco 7000 Family)

The ATM Inverse ARP mechanism is applicable to networks that use PVCs, where connections are established but the network addresses of the remote ends are not known. A server function is not used in this mode of operation.

In a PVC environment, configure the ATM Inverse ARP mechanism by performing the following tasks, starting in global configuration mode:

Task Command
Step 1 Specify an AIP interface and enter interface configuration mode. interface atm slot/01
Step 2 Create a PVC and enable Inverse ARP on it. atm pvc vcd vci aal5snap [inarp minutes] 2
Step 3 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 Additional options are permitted in this command, but the order of options is important. For more information about the complete atm pvc command and the order of keywords and arguments, refer to the Wide-Area Networking Command Reference.

Repeat Step 2 for each PVC you want to create.

The inarp minutes interval specifies how often Inverse ARP datagrams will be sent on this virtual circuit. The default value is 15 minutes.


Note The ATM ARP and Inverse ATM ARP mechanisms work with IP only. All other protocols require map-list command entries to operate.

For an example of configuring the ATM Inverse ARP mechanism, see the "ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 7000 Family)" section later in this chapter.

Configure Traffic Shaping for ATM SVCs on the Cisco 7000 Family

When you configure SVCs, you can define an ATM class to add support for traffic shaping on ATM SVCs. This applies a map class to an ATM interface. When an outgoing call is made by a static map client, or by a classical IP over ATM client, a map class will be determined for the call.

You must enter map-class configuration mode before you can define an ATM class. To enter map-class configuration mode and specify the ATM class for an ATM interface, perform the following tasks in global configuration mode:

Task Command
Enter map-class configuration mode, specifying a map-class name. map-class atm class-name
Specify an ATM class for an ATM interface. atm class class-name

You can specify that an SVC be established on an ATM interface using only signaled traffic parameters. When you configure strict traffic-shaping on the router ATM interface, an SVC is established only if traffic shaping can be provided for the transmit cell flow per the signaled traffic parameters. If such shaping cannot be provided, the SVC is released.

If you do not configure strict traffic-shaping on the router ATM interface, an attempt is made to establish an SVC with traffic shaping for the transmit cell flow per the signaled traffic parameters. If such shaping cannot be provided, the SVC is installed with default shaping parameters; that is, it behaves as though a PVC were created without specifying traffic parameters.

To specify that an SVC be established on an ATM interface using only signaled traffic parameters, perform the following task in interface configuration mode:

Task Command
Specify that an SVC be established on an ATM interface using only signaled traffic parameters. atm sig-traffic-shaping strict

Customize the AIP on the Cisco 7000 Family

You can customize the AIP. The features you can customize have default values that will most likely suit your environment and probably need not be changed. However, you might need to enter configuration commands, depending upon the requirements for your system configuration and the protocols you plan to route on the interface. Perform the tasks in the following sections if you need to customize the AIP:

Configure the Rate Queue (Cisco 7000 Family)

A rate queue defines the speed at which individual virtual circuits will transmit data to the remote end. You can configure permanent rate queues, allow the software to set up dynamic rate queues, or perform some combination of the two. The software dynamically creates rate queues when an atm pvc command specifies a peak/average rate that does not match any user-configured rate queue. The software dynamically creates all rate queues if you have not configured any.

Use Dynamic Rate Queues (Cisco 7000 Family)

The Cisco IOS software automatically creates rate queues as necessary to satisfy the requests of atm pvc commands. The peak rate for a virtual circuit descriptor (VCD) is set to the maximum that the physical layer interface module (PLIM) will allow, and the average rate is set equal to the peak rate; then a rate queue is dynamically created for the peak rate of the VCD.

If dynamic rate queues do not satisfy your traffic shaping needs, you can configure permanent rate queues.

See the "Dynamic Rate Queue Examples (Cisco 7000 Family)" section for examples of different rate queues created in response to atm pvc commands.

Configure a Permanent Rate Queue (Cisco 7000 Family)

The AIP supports up to eight different peak rates. The peak rate is the maximum rate, in kilobits per second, at which a virtual circuit can transmit. Once attached to this rate queue, the virtual circuit is assumed to have its peak rate set to that of the rate queue. The rate queues are broken into a high-priority (0 through 3) and low-priority (4 through 7) bank.

You can configure each permanent rate queue independently to a portion of the overall bandwidth available on the ATM link. The combined bandwidths of all rate queues should not exceed the total bandwidth available. A warning message is displayed if you attempt to configure the combined rate queues beyond what is available to the AIP. The total bandwidth depends on the PLIM (see the "AIP ATM Interface Types" section in the "Wide-Area Networking Overview" chapter.)

To set a permanent rate queue, perform the following task in interface configuration mode:

Task Command
Configure a permanent rate queue, which defines the maximum speed at which an individual virtual circuit transmits data to a remote ATM host. atm rate-queue queue-number speed

Configure MTU Size (Cisco 7000 Family)

Each interface has a default maximum packet size or maximum transmission unit (MTU) size. On the AIP, this number defaults to 4470 bytes; the maximum is 9188 bytes. The MTU can be set on a per-sub-interface basis as long as the interface MTU is as large or larger than the largest sub-interface MTU. To set the maximum MTU size, perform the following task in interface configuration mode:

Task Command
Set the maximum MTU size. mtu bytes1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

Set the SONET PLIM (Cisco 7000 Family)

The default SONET PLIM is STS-3C. To set the SONET PLIM to STM-1, perform the following task in interface configuration mode:

Task Command
Set the SONET PLIM to STM-1. atm sonet stm-1

Set Loopback Mode (Cisco 7000 Family)

To loop all packets back to the AIP instead of the network, perform the following task in interface configuration mode:

Task Command
Set loopback mode. loopback [diagnostic | line]

Set the Exception-Queue Length (Cisco 7000 Family)

The exception queue is used for reporting ATM events, such as CRC errors. By default, it holds 32 entries; the range is 8 to 256. It is unlikely you will need to configure the exception queue length; if you do, perform the following task in interface configuration mode:

Task Command
Set the exception queue length. atm exception-queue number

Limit the Number of Virtual Circuits (Cisco 7000 Family)

By default, the ATM interface allows the maximum of 2048 virtual circuits. However, you can configure a lower number, thereby limiting the number of virtual circuits on which the AIP allows segmentation and reassembly to occur. Limiting the number of virtual circuits does not affect the VPI-VCI pair of each virtual circuit.

To set the maximum number of virtual circuits supported (including PVCs and SVCs), perform the following task in interface configuration mode:

Task Command
Limit the number of virtual circuits. atm maxvc number

Set the Raw-Queue Size (Cisco 7000 Family)

The raw queue is used for raw ATM cells, which include Operation, Administration, and Maintenance (OAM) and Interim Local Management Interface (ILMI) cells. ILMI is a means of passing information to the router, including information about virtual connections and addresses.

The raw-queue size is in the range of 8 to 256 cells; the default is 32 cells. To set the raw-queue size, perform the following task in interface configuration mode:

Task Command
Set the raw-queue size. atm rawq-size number

Configure Buffer Sizes (Cisco 7000 Family)

The number of receive buffers determines the maximum number of reassemblies that the AIP can perform simultaneously. The number of buffers defaults to 256, although it can be in the range from 0 to 512. To set the number of receive buffers, perform the following task in interface configuration mode:

Task Command
Set the number of receive buffers. atm rxbuff number

The number of transmit buffers determines the maximum number of fragmentations that the AIP can perform simultaneously. The number of buffers defaults to 256, although it can be in the range from 0 to 512. To set the number of transmit buffers, perform the following task in interface configuration mode:

Task Command
Set the number of transmit buffers. atm txbuff number

Set the VCI-to-VPI Ratio (Cisco 7000 Family)

By default, the AIP supports 1024 VCIs per VPI. This value can be in the range of 16 to 1024. This value controls the memory allocation in the AIP to deal with the VCI table. It defines only the maximum number of VCIs to support per VPI.

To set the maximum number of VCIs to support per VPI and limit the highest VCI accordingly, perform the following task in interface configuration mode:

Task Command
Set the number of VCIs per VPI. atm vc-per-vp number

Set the Source of the Transmit Clock (Cisco 7000 Family)

By default, the AIP expects the ATM switch to provide transmit clocking. To specify that the AIP generate the transmit clock internally for SONET and E3 PLIM operation, perform the following task in interface configuration mode:

Task Command
Specify that the AIP generate the transmit clock internally. atm clock internal

Configure ATM Subinterfaces for SMDS Networks on the Cisco 7000 Family

An ATM adaption layer (AAL) defines the conversion of user information into cells by segmenting upper-layer information into cells at the transmitter and reassembling them at the receiver. AAL1 and AAL2 handle isochronous traffic, such as voice and video, and are not relevant to the router. AAL3/4 and AAL5 support data communications by segmenting and reassembling packets. Starting with Cisco IOS Release 10.2, we support both AAL3/4 and AAL5.

Our implementation of the AAL3/4 encapsulates each AAL3/4 packet in a Switched Multimegabit Data Service (SMDS) header and trailer. This feature supports both unicast and multicast addressing, and provides subinterfaces for multiple AAL3/4 connections over the same physical interface.


Note Each
subinterface configured to support AAL3/4 is allowed only one SMDS E.164 unicast address and one E.164 multicast address. The multicast address is used for all broadcast operations. In addition, only one virtual circuit is allowed on each subinterface that is being used for AAL3/4 processing, and it must be an AAL3/4 virtual circuit.

Support for AAL3/4 on an ATM interface requires static mapping of all protocols except IP. However, dynamic routing of IP can coexist with static mapping of other protocols on the same ATM interface.

To configure an ATM interface for SMDS networks, perform the following tasks in interface configuration mode:

Task Command
Step 1 Enable AAL3/4 support on the affected ATM subinterface. atm aal aal3/4
Step 2 Provide an SMDS E.164 unicast address for the subinterface. atm smds-address address 
Step 3 Provide an SMDS E.164 multicast address. atm multicast address
Step 4 Configure a virtual path filter for the affected ATM subinterface. atm vp-filter hex value
Step 5 Create an AAL3/4 PVC. atm pvc vcd vpi vci aal34smds

The virtual path filter provides a mechanism for specifying which VPIs (or a range of VPIs) will be used for AAL3/4 processing during datagram reassembly. All other VPIs are mapped to AAL5 processing. For more information about the way the atm vp-filter command works and the effect of selecting specific values, refer to the Wide-Area Networking Command Reference.

After configuring the ATM interface for SMDS networks, configure the interface for standard protocol configurations, as needed. For more information about protocol configuration, refer to the relevant chapters of the Network Protocols Configuration Guide, Part 1 and the Network Protocols Configuration Guide, Part 2, and Network Protocols Configuration Guide, Part 3.

For examples of configuring an ATM interface for AAL3/4 support, see the "PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 7000 Family)" section later in this chapter.

Limit the Message Identifiers Allowed on Virtual Circuits (Cisco 7000 Family)

Message identifier (MID) numbers are used by receiving devices to reassemble cells from multiple sources into packets.

To ensure that the message identifiers are unique at the receiving end and, therefore, that messages can be reassembled correctly, you can limit the number of message identifiers allowed on a virtual circuit and assign different ranges of message identifiers to different PVCs.

To limit the number of message identifier numbers allowed on each virtual circuit and to assign different ranges of message identifiers to different PVCs, complete the following tasks in interface configuration mode:

Task Command
Limit the number of message identifiers allowed per virtual circuit. atm mid-per-vc maximum
Limit the range of message identifier values used on a PVC. atm pvc vcd vpi vci aal-encap midlow midhigh

The maximum number of message identifiers per virtual circuit is set at 16 by default, and may take only the values 16, 32, 64, 128, 256, 512, or 1024.

The default value for both midlow and midhigh is zero.

Set the Virtual Path Filter Register (Cisco 7000 Family)

The virtual path filter allows you to specify which VPI or range of VPIs will be used for AAL3/4 processing. The default value of the AIP's virtual path filter register is 0x7B. To set the AIP virtual path filter register, perform the following task in interface configuration mode:

Task Command
Set the virtual path filter register. atm vp-filter hexvalue

Configure Transparent Bridging for ATM on the Cisco 7000 Family

Our implementation of transparent bridging over ATM allows the spanning tree for an interface to support two different types of MAC addresses: E.164 addresses for AAL3/4-SMDS encapsulations, and virtual circuit descriptors (VCDs) for AAL5-LLC Subnetwork Access Protocol (SNAP) encapsulations.  

If the relevant interface or subinterface is explicitly put into a bridge group, as described in the "Enable Fast-Switched Transparent Bridging for SNAP PVCs (Cisco 7000 Family)" section, AAL5-SNAP encapsulated bridge packets on a PVC are fast-switched.

If the relevant interface or subinterface is explicitly put into a bridge group, as described in the "Enable Process-Switched Transparent Bridging for SMDS Subinterfaces (Cisco 7000 Family)" section, AAL3/4-SMDS encapsulated bridge packets are process-switched.

Our bridging implementation supports IEEE 802.3 frame formats and IEEE 802.10 frame formats. The router can accept IEEE 802.3 frames with or without frame check sequence (FCS). When the router receives frames with FCS (RFC 1483 bridge frame formats with 0x0001 in the PID field of the SNAP header), it strips off the FCS and forwards the frame as necessary. All IEEE 802.3 frames that originate at or are forwarded by the router are sent as 802.3 bridge frames without FCS (bridge frame formats with 0x0007 in the PID field of the SNAP header).


Note Transparent bridging for ATM on the Cisco 7000 works only on AAL3/4-SMDS encapsulations (process-switched) and AAL5-LLC/SNAP PVCs (fast-switched). AAL5-MUX and AAL5-NLPID
bridging are not yet supported Cisco 7000. Transparent bridging for ATM also does not operate in a switched virtual circuit (SVC) environment.

Enable Process-Switched Transparent Bridging for SMDS Subinterfaces (Cisco 7000 Family)

To configure transparent bridging for AAL3/4 SMDS subinterfaces, complete the following steps beginning in interface configuration mode:

Task Command
Step 1 Specify an AIP interface and, optionally, a subinterface. interface atm slot/0[.subinterface]1
Step 2 Assign a source IP address and subnet mask to the interface, if needed. ip address ip-address mask2
Step 3 Enable an AAL3/4 (SMDS) subinterface. atm aal aal3/4
Step 4 Configure a virtual path filter for the affected ATM subinterface. atm vp-filter hexvalue
Step 5 Provide an SMDS E.164 unicast address for the subinterface. atm smds-address address 
Step 6 Provide an SMDS E.164 multicast address. atm multicast address
Step 7 Create an AAL3/4 PVC. atm pvc vcd vpi vci aal34smds
Step 8 Assign the interface to a bridge group. bridge-group group3
Step 9 Return to global configuration mode. exit
Step 10 Define the type of spanning tree protocol as DEC. bridge group protocol dec3

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.
3 This command is documented in the "Transparent Bridging Commands" chapter in the Bridging and IBM Networking Command Reference.

No other configuration steps are required. All spanning tree updates are sent to the multicast E.164 address specified in Step 6. Routers on the remote end learn the unicast address of this router from the packets this router sends to them.

For an example of transparent bridging for an SMDS interface, see the "Transparent Bridging on an SMDS Subinterface Example (Cisco 7000 Family)" section.

Enable Fast-Switched Transparent Bridging for SNAP PVCs (Cisco 7000 Family)

To configure transparent bridging for LLC/SNAP PVCs, compete the following steps beginning in interface configuration mode:

Task Command
Step 1 Specify an AIP interface and, optionally, a subinterface. interface atm slot/0[.subinterface]1
Step 2 Assign a source IP address and subnet mask to the interface, if needed. ip address ip-address mask2
Step 3 Create one or more PVCs using AAL5-SNAP encapsulation. atm pvc vcd vpi vci aal5snap

atm pvc vcd vpi vci aal5snap

atm pvc vcd vpi vci aal5snap

Step 4 Assign the interface to a bridge group. bridge-group group3
Step 5 Return to global configuration mode. exit
Step 6 Define the type of spanning tree protocol as DEC. bridge group protocol dec3

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.
3 This command is documented in the "Transparent Bridging Commands" chapter in the Bridging and IBM Networking Command Reference.

No other configuration is required. Spanning tree updates are broadcast to all AAL5-SNAP virtual circuits that exist on the ATM interface. Only the AAL5-SNAP virtual circuits on the specific subinterface receive the updates. The router does not send spanning tree updates to AAL5-MUX and AAL5-NLPID virtual circuits. For an example of transparent bridging for an AAL5-SNAP PVC, see the "Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 7000 Family)" section.

Cisco 4500 Series Configuration Task List

To configure ATM in Cisco 4500 series (Cisco 4500 and Cisco 4700) routers, complete the tasks in the following sections. The first task is required, and then you must configure at least one PVC or SVC. The virtual circuit options you configure must match in three places: on the router, on the ATM switch, and at the remote end of the PVC or SVC connection. The remaining tasks are optional.


Note All tasks in this list apply to both the Cisco 4500 and the Cisco 4700 routers.

See the "Cisco 4500 Series Configuration Examples" section for configuration examples.

Enable the ATM Interface on the Cisco 4500 Series

This section describes how to begin configuring the network processor module (NPM). The Cisco 4500 and Cisco 4700 identify an interface address by its unit number. To begin to configure the NPM, start the following task in privileged EXEC mode:

Task Command
Step 1 At the privileged EXEC prompt, enter configuration mode from the terminal. configure1
[terminal] <CR>
Step 2 Specify an ATM interface. interface atm number2
Step 3 If IP routing is enabled on the system, optionally assign a source IP address and subnet mask to the interface. ip address ip-address mask3

1 This command is documented in the "System and Configuration File Load Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
3 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.

To enable the ATM interface, perform the following task in interface configuration mode:

Task Command
Change the shutdown state to up and enable the ATM interface, thereby starting the sequence and reassembly (SAR) operation on the interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

The no shutdown command passes an enable command to the NPM, which then begins segmentation and reassembly (SAR) operations. It also causes the NPM to configure itself based on the previous configuration commands sent.

Configure PVCs on the Cisco 4500 Series

To use a permanent virtual circuit (PVC), you must configure the PVC into both the router and the ATM switch. PVCs remain active until the circuit is removed from either configuration.

All virtual circuit characteristics listed in the section "NPM Virtual Circuits" in the "Wide-Area Networking Overview" chapter apply to these PVCs. When a PVC is configured, all the configuration options are passed on to the NPM. These PVCs are writable into the nonvolatile RAM (NVRAM) as part of the Route Processor (RP) configuration and are used when the RP image is reloaded.

Some ATM switches might have point-to-multipoint PVCs that do the equivalent of broadcasting. If a point-to-multipoint PVC exists, then that PVC can be used as the sole broadcast PVC for all multicast requests.

To configure a PVC, perform the tasks in the following sections. The first two tasks are required; the third task is optional:

Create a PVC (Cisco 4500 Series)

To create a PVC on the NPM interface, perform the following task in interface configuration mode:

Task Command
Create a PVC. atm pvc vcd vpi vci aal-encap [[midlow midhigh] [peak average burst]] [oam seconds] [inarp minutes]

When you create a PVC, you create a virtual circuit descriptor (VCD) and attach it to the VPI and VCI. A VCD is an NPM-specific mechanism that identifies to the NPM which VPI-VCI pair to use for a particular packet. The NPM requires this feature to manage the packets for transmission. The number chosen for the VCD is independent of the VPI-VCI pair used.

When you create a PVC, you also specify the AAL and encapsulation. A rate queue is used that matches the peak and average rate selections, which are specified in kilobits per second. Omitting a peak and average value causes the PVC to be connected to the highest bandwidth rate queue available. In this case, the peak and average values are equal.

See examples of PVC configurations on the Cisco 4500 in the section "Cisco 4500 Series Configuration Examples" at the end of this chapter.

Map a Protocol Address to a PVC (Cisco 4500 Series)

The ATM interface supports a static mapping scheme that identifies the ATM address of remote hosts or routers. This address is specified as a virtual circuit descriptor (VCD) for a PVC (or an NSAP address for SVC operation). This section describes how to map a PVC to an address, which is a required task if you are configuring a PVC.

You enter mapping commands as groups. You first create a map list and then associate it with an interface. Begin the following tasks in global configuration mode:

Task Command
Step 1 Create a map list by naming it, and enter map-list configuration mode. map-list name
Step 2 Associate a protocol and address to a specific virtual circuit. protocol protocol-address atm vc vcd [broadcast]
Step 3 Associate a protocol and address to a different virtual circuit. protocol protocol-address atm vc vcd [broadcast]
Step 4 Specify a Cisco 4500 series interface and enter interface configuration mode. interface atm number1
Step 5 Associate a map list to an interface. map-group name

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

A map list can contain multiple map entries, as Steps 2 and 3 in the preceding task table illustrate. The broadcast keyword specifies that this map entry is to be used when the corresponding protocol sends broadcast packets to the interface (for example, any network routing protocol updates). If you do not specify broadcast, the ATM software is prevented from sending routing protocol updates to the remote host.

Step 5 illustrates that when the map list is complete, you associate the list with an ATM interface by using the same name argument.

You can create multiple map lists, but you can associate only one map list with an interface. Different map lists can be associated with different interfaces. See the examples at the end of this chapter.

Configure Communication with the ILMI (Cisco 4500 Series)

You can configure a PVC for communication with the Interim Local Management Interface (ILMI) so the router can receive SNMP traps and new network prefixes. The recommended vpi and vci values for the ILMI PVC are 0 and 16, respectively. To configure ILMI communication, complete the following task in interface configuration mode:

Task Command
Create an ILMI PVC on a major interface. atm pvc vcd vpi vci ilmi

Note This ILMI PVC can be set up only on a major interface, not on the subinterfaces.

Once you have configured an ILMI PVC, you can optionally enable the ILMI keepalive function by completing the following task in interface configuration mode:

Optionally, enable ILMI keepalives and set the interval between keepalives. atm ilmi-keepalive [seconds]

No other configuration steps are required.

ILMI address registration for receipt of SNMP traps and new network prefixes is enabled by default. The ILMI keepalive function is disabled by default; when enabled, the default interval between keepalives is 3 seconds.

Configure Transmission of Loopback Cells to Verify Connectivity (Cisco 4500 Series)

You can optionally configure the PVC to send OAM F5 loopback cells to verify connectivity on the virtual circuit. The remote end must respond by echoing back such cells.

To configure the transmission of OAM F5 loopback cells, add the oam keyword to the atm pvc command, as shown in the following task:

Task Command
Configure transmission of OAM F5 cells on the PVC, specifying how often OAM F5 cells should be sent. atm pvc vcd vpi vci aal-encap [[midlow midhigh]
[
peak average burst]] [oam seconds] [inarp minutes]

Configure SVCs on the Cisco 4500 Series

ATM switched virtual circuit (SVC) service operates much like X.25 SVC service, although ATM allows much higher throughput. Virtual circuits are created and released dynamically, providing user bandwidth on demand. This service requires a signaling protocol between the router and the switch.

The ATM signaling software provides a method of dynamically establishing, maintaining, and clearing ATM connections at the User-Network Interface (UNI). The ATM signaling software conforms to ATM Forum UNI 3.0 or ATM Forum UNI 3.1, depending on which version has been selected by ILMI or configured.

In UNI mode, the user is the router and the network is an ATM switch. This is an important distinction. The Cisco router does not perform ATM-level call routing; the ATM switch does the ATM call routing. The router routes packets through the resulting circuit. The router is viewed as the user and the LAN interconnection device at the end of the circuit, and the ATM switch is viewed as the network.

Figure 11 illustrates the router position in a basic ATM environment. The router is used primarily to interconnect LANs via an ATM network. The workstation connected directly to the destination ATM switch illustrates that you can connect not only routers to ATM switches, but also any computer with an ATM interface that conforms to the ATM Forum UNI specification.


Figure 11: Basic ATM Environment


You must complete the tasks in the following sections to use SVCs:

The tasks in the following sections are optional SVC tasks for customizing your network. These tasks are considered advanced; the default values are almost always adequate. You should not have to perform these tasks unless you need to customize your particular SVC connection.

Configure the PVC That Performs SVC Call Setup (Cisco 4500 Series)

Unlike X.25 service, which uses in-band signaling (connection establishment done on the same circuit as data transfer), ATM uses out-of-band signaling. This means that one dedicated PVC exists between the router and the ATM switch, over which all SVC call establishment and call termination requests flow. After the call is established, data transfer occurs over the SVC, from router to router. The signaling that accomplishes the call setup and teardown is called Layer 3 signaling or the Q.2931 protocol.

For out-of-band signaling, a signaling PVC must be configured before any SVCs can be set up. Figure 12 illustrates a signaling PVC from the source router to the ATM switch used to set up two SVCs. This is a fully meshed network; workstations A, B, and C all can communicate with each other.


Figure 12:
One or More SVCs Require a Signaling PVC


To configure the signaling PVC for all SVC connections, perform the following task in interface configuration mode:

Task Command
Configure the signaling PVC for a major interface that uses SVCs. atm pvc vcd vpi vci qsaal

Note This signaling PVC can be set up only on a major interface, not on the subinterfaces.

The VPI and VCI values must be configured consistently with the local switch. The standard value of VPI is 0; the standard value of VCI is 5.

See the section "SVCs in a Fully Meshed Network Example (Cisco 4500 Series)" at the end of this chapter for a sample ATM signaling configuration.

Configure the NSAP Address (Cisco 4500 Series)

Every ATM interface involved with signaling must be configured with an network service access point (NSAP) address. The NSAP address is the ATM address of the interface and must be unique across the network.

Complete one of the following tasks to configure an NSAP address:

If you choose to configure the end station ID (ESI) and selector fields, you also must configure a PVC to communicate with the switch via ILMI. The switch then provides the prefix field of the NSAP address.

Configure the Complete NSAP Address Manually (Cisco 4500 Series)

When you configure the ATM NSAP address manually, you must enter the entire address in hexadecimal format since each digit entered represents a hexadecimal digit. To represent the complete NSAP address, you must enter 40 hexadecimal digits in the following format:

XX.XXXX.XX.XXXXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XXXX.XX

Note  All ATM NSAP addresses may be entered in the dotted hexadecimal format shown, which conforms to the UNI specification. The dotted method provides some validation that the address is a legal value. If you know your address format is correct, the dots may be omitted.

Because the interface has no default NSAP address, you must configure the NSAP address for SVCs. To set the ATM interface's source NSAP address, perform the following task in interface configuration mode:

Task Command
Configure the ATM NSAP address for an interface. atm nsap-address nsap-address

The following example assigns NSAP address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12 to ATM interface 0:

interface ATM 0
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12

You can display the ATM address for the interface by executing the show interface atm command.

Configure the ESI and Selector Fields (Cisco 4500 Series)

To use this method of entering the router's NSAP address, the switch must be capable of delivering the NSAP address prefix to the router via ILMI and the router must be configured with a PVC for communication with the switch via ILMI.

To configure the router to get the NSAP prefix from the switch and use locally entered values for the remaining fields of the address, complete the following tasks in interface configuration mode:

Task Command
Step 1 Configure a PVC for communicating with the switch via ILMI. atm pvc vcd 0 16 ilmi
Step 2 Enter the ESI and selector fields of the NSAP address. atm esi-address esi.selector

In the atm esi-address command, the esi argument is 6 hexadecimal bytes long (12 digits), and the selector argument is one hexadecimal byte long (2 digits).

You can also specify a keepalive interval for the ILMI PVC. See the "Configure Communication with the ILMI (Cisco 4500 Series)" section for more information.

The following example on a Cisco 4500 router assigns the ESI and selector field values and sets up the ILMI PVC:

interface ATM 0
atm pvc 2 0 16 ilmi
atm esi-address 345678901234.12

Configure the ATM ESI Address (Cisco 4500 Series)

You can enter the end station ID (ESI) and selector byte fields of the ATM NSAP address using the atm esi-address interface configuration command. The NSAP address prefix is filled in via ILMI from the ATM switch.

Before Cisco IOS Release 11.0, ATM addresses were configured on the router only by use of the atm nsap-address interface configuration command. The complete 20-byte NSAP (40 hexadecimal characters) had to be configured.

The atm esi-address command allows you to configure the ATM address by entering the ESI (12 hexadecimal characters) and the selector byte (2 hexadecimal characters). The ATM prefix (26 hexadecimal characters) is provided by the ATM switch. To get the prefix from the ATM switch, the ILMI PVC must be configured on the router and the ATM switch must be able to supply a prefix via ILMI.

The atm esi-address and atm nsap-address commands are mutually exclusive. Configuring the router with the atm esi-address command negates the atm nsap-address setting, and vice versa.

The ILMI PVC must be configured in order to get an NSAP address prefix from the switch.

Configure the Idle Timeout Interval (Cisco 4500 Series)

You can specify an interval of inactivity after which any idle SVC on an interface is disconnected. This timeout interval might help control costs and free router memory and other resources for other uses.

To change the idle timeout interval, perform the following task in interface configuration mode:

Task Command
Configure the interval of inactivity after which an idle SVC will be disconnected. atm idle-timeout seconds

The default idle timeout interval is 300 seconds (5 minutes).

Configure Point-to-Multipoint Signaling (Cisco 4500 Series)

Point-to-multipoint signaling (or multicasting) allows the router to send one packet to the ATM switch and have the switch replicate the packet to the destinations. It replaces pseudobroadcasting on specified virtual circuits for protocols configured for broadcasting.

You configure multipoint signaling on an ATM interface after you have mapped protocol addresses to NSAPs and configured one or more protocols for broadcasting.

After multipoint signaling is set, the router uses existing static map entries that have the broadcast keyword set to establish multipoint calls. The call is established to the first destination with a Setup message. Additional parties are added to the call with AddParty messages each time a multicast packet is sent. One multipoint call will be established for each logical subnet of each protocol that has the broadcast keyword set.

To configure multipoint signaling on an ATM interface, complete the following tasks beginning in global configuration mode. The first task is required to configure this feature; the others are optional.

Task Command
Step 1 Specify the ATM interface. interface atm number1
Step 2 Provide a protocol address for the interface. protocol protocol-address mask
Step 3 Associate a map list to the interface. map-group name
Step 4 Provide an ATM NSAP address for the interface. atm nsap-address nsap-address
Step 5 Configure the signaling PVC for the interface that uses SVCs. atm pvc vcd vpi vci qsaal
Step 6 Associate a map list with the map group. map-list name
Step 7 Configure a broadcast protocol for the remote NSAP address on the SVC.

Repeat this step for other NSAP addresses, as needed.

protocol protocol-address atm-nsap atm-nsap-address broadcast
Step 8 Enable multipoint signaling to the ATM switch. atm multipoint-signaling
Step 9 Limit the frequency of sending AddParty messages (optional). atm multipoint-interval interval

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

If multipoint virtual circuits are closed, they are reopened with the next multicast packet. Once the call is established, additional parties are added to the call when additional multicast packets are sent. If a destination never comes up, the router constantly attempts to add it to the call by means of multipoint signaling.

Change Traffic Values (Cisco 4500 Series)

The tasks in this section are optional and advanced. The ATM signaling software can specify to the NPM card and the ATM switch a limit on how much traffic the source router will be sending. It provides this information in the form of traffic parameters. (These parameters have default values.) The ATM switch in turn sends these parameters as requested by the source to the ATM destination node. If the destination cannot provide such capacity levels, the call may fail (for Cisco 4500 series behavior, see the per-interface atm sig-traffic-shaping strict command in the Wide-Area Networking Command Reference). There is a single attempt to match traffic parameters.

This section describes how to change traffic values to customize your SVC connection. The individual tasks that separately specify peak, sustainable, or burst values for an SVC are analogous to the peak, average, and burst values defined when you create a PVC. Valid values for the peak rate on the Cisco 4500 series are from 56 kbps to the PLIM rate, valid values for the average rate are from 1 kbps to the peak rate, and valid values for the maximum burst size are from 1 cell to 65535 cells.

Forward commands apply to the flow of cells from the source router to the destination router. Backward commands apply to the flow of cells from the destination router to the source router.

Most of the SVC traffic parameters include the concept of cell loss priority (CLP). CLP defines two levels of cell importance:

Figure 13 illustrates a source and destination router implementing traffic settings that correspond end-to-end. The value for the forward command at the source router corresponds to the value for the backward command at the destination router.


Figure 13: Source and Destination Routers Have Corresponding Traffic Settings


You can define map lists and map groups to tie specified SVCs to the protocol addresses of remote hosts and to specify whether broadcast protocols are supported. Then you can define map classes and specify the traffic parameters needed for the specified protocol traffic on those SVCs.

You must enter map-class configuration mode before you can change the traffic values from their default values. To enter map-class configuration mode, perform the following task in global configuration mode:

Task Command
Enter map-class configuration mode, specifying a map-class name. map-class atm class-name

If a map class with the specified name does not exist, the router creates a new one. All the following commands apply to the named map class.

See the "Traffic Parameters Example (Cisco 4500 Series)" section for an example defining map classes, map groups, map lists, and traffic parameters.

To change the traffic values from their default values, perform one or more of the following tasks in map-class configuration mode:

Task Command
Set the source-to-destination peak cell rate for high-priority cells. atm forward-peak-cell-rate-clp0 rate
Set the destination-to-source peak cell rate for high-priority cells. atm backward-peak-cell-rate-clp0 rate
Set the source-to-destination peak cell rate for the aggregate of low-priority and high-priority cells. atm forward-peak-cell-rate-clp1 rate
Set the destination-to-source peak cell rate for the aggregate of low-priority and high-priority cells. atm backward-peak-cell-rate-clp1 rate
Set the source-to-destination sustainable cell rate for high-priority cells. atm forward-sustainable-cell-rate-clp0 rate
Set the destination-to-source sustainable cell rate for high-priority cells. atm backward-sustainable-cell-rate-clp0 rate
Set the source-to-destination sustainable cell rate for the aggregate of low-priority and high-priority cells. atm forward-sustainable-cell-rate-clp1 rate
Set the destination-to-source sustainable cell rate for the aggregate of low-priority and high-priority cells. atm backward-sustainable-cell-rate-clp1 rate
Set the source-to-destination burst size for high-priority cells. atm forward-max-burst-size-clp0 cell-count
Set the destination-to-source burst size for high-priority cells. atm backward-max-burst-size-clp0 cell-count
Set the source-to-destination burst size for the aggregate of low-priority and high-priority cells. atm forward-max-burst-size-clp1 cell-count
Set the destination-to-source burst size for the aggregate of low-priority and high-priority cells. atm backward-max-burst-size-clp1 cell-count

Configure SSCOP (Cisco 4500 Series)

The Service-Specific Connection-Oriented Protocol (SSCOP) resides in the service-specific convergence sublayer (SSCS) of the ATM adaptation layer (AAL). SSCOP is used to transfer variable-length service data units (SDUs) between users of SSCOP. SSCOP provides for the recovery of lost or corrupted SDUs.


Note The tasks in this section customize the SSCOP feature to a particular network or environment and are optional. The features have default values and are valid in most installations. Before customizing these features, you should have a good understanding of SSCOP and the network involved.

Set the Poll Timer (Cisco 4500 Series)

The poll timer controls the maximum time between transmission of a POLL PDU when SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the poll timer from the default value of 10 seconds, perform the following task in interface configuration mode:

Task Command
Set the poll timer. sscop poll-timer seconds

Set the Keepalive Timer (Cisco 4500 Series)

The keepalive timer controls the maximum time between transmission of a POLL PDU when no SD or SDP PDUs are queued for transmission or are outstanding pending acknowledgments. To change the keepalive timer from the default value of 30 seconds, perform the following task in interface configuration mode:

Task Command
Set the keepalive timer. sscop keepalive-timer seconds

Set the Connection Control Timer (Cisco 4500 Series)

The connection control timer determines the time between transmission of BGN, END, or RS (resynchronization) PDUs as long as an acknowledgment has not been received. Connection control performs the establishment, release, and resynchronization of an SSCOP connection.

To change the connection control timer from the default value of 10 seconds, perform the following task in interface configuration mode:

Task Command
Set the connection control timer. sscop cc-timer seconds

To change the retry count of the connection control timer from the default value of 10, perform the following task in interface configuration mode:

Task Command
Set the number of times that SSCOP will retry to transmit BGN, END, or RS PDUs when they have not been acknowledged. sscop max-cc retries

Set the Transmitter and Receiver Windows (Cisco 4500 Series)

A transmitter window controls how many packets can be transmitted before an acknowledgment is required. To change the transmitter's window from the default value of 7, perform the following task in interface configuration mode:

Task Command
Set the transmitter's window. sscop send-window packets

A receiver window controls how many packets can be received before an acknowledgment is required. To change the receiver's window from the default value of 7, perform the following task in interface configuration mode:

Task Command
Set the receiver's window. sscop rcv-window packets

Close an SVC (Cisco 4500 Series)

You can disconnect an idle SVC by completing the following task in EXEC mode:

Task Command
Close the signaling PVC for an SVC. atmsig close atm number vcd

Configure Classical IP and ARP over ATM on the Cisco 4500 Series

Cisco implements both the ATM ARP server and ATM ARP client functions described in RFC 1577. RFC 1577 models an ATM network as a logical IP subnetwork on a LAN.

The tasks required to configure classical IP and ARP over ATM depend on whether the environment uses SVCs or PVCs.

Configure Classical IP and ARP in an SVC Environment (Cisco 4500 Series)

The ATM ARP mechanism is applicable to networks that use SVCs. It requires a network administrator to configure only the device's own ATM address and that of a single ATM ARP server into each client device. When the client makes a connection to the ATM ARP server, the server sends ATM Inverse ARP requests to learn the IP network address and ATM address of the client on the network. It uses the addresses to resolve future ATM ARP requests from clients. Static configuration of the server is not required or needed. 

In Cisco's implementation, the ATM ARP client tries to maintain a connection to the ATM ARP server. The ATM ARP server can tear down the connection, but the client attempts once each minute to bring the connection back up. No error messages are generated for a failed connection, but the client will not route packets until the ATM ARP server is connected and translates IP network addresses.

For each packet with an unknown IP address, the client sends an ATM ARP request to the server. Until that address is resolved, any IP packet routed to the ATM interface will cause the client to send another ATM ARP request. When the ARP server responds, the client opens a connection to the new destination so that any additional packets can be routed to it.

Cisco routers may be configured as ATM ARP clients to work with any ATM ARP server conforming to RFC 1577. Alternatively, one of the Cisco routers in a logical IP subnet (LIS) may be configured to act as the ATM ARP server itself. In this case, it automatically acts as a client as well. To configure classical IP and ARP in an SVC environment, perform one of the following tasks:

Configure as an ATM ARP Client (Cisco 4500 Series)

In an SVC environment, configure the ATM ARP mechanism on the interface by performing the following tasks in interface configuration mode: 

Task Command
Step 1 Specify an ATM interface. interface atm number1
Step 2 Specify the ATM address of the interface. atm nsap-address nsap-address
Step 3 Specify the IP address of the interface. ip address address mask2
Step 4 Specify the ATM address of the ATM ARP server. atm arp-server nsap nsap-address
Step 5 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.

You can designate the current router as the ATM ARP server in Step 4 by typing self instead of the NSAP address.

For an example of configuring the ATM ARP client, see the "ATM ARP Client Configuration in an SVC Environment Example (Cisco 4500 Series)" section later in this chapter.

Configure as an ATM ARP Server (Cisco 4500 Series)

Cisco's implementation of the ATM ARP server supports a single, nonredundant server per logical IP subnetwork (LIS) and supports one ATM ARP server per subinterface. Thus, a single NPM card can support multiple ARP servers by using multiple subinterfaces.

To configure the ATM ARP server, complete the following tasks in interface configuration mode:

Task Command
Step 1 Specify an ATM interface. interface atm number1
Step 2 Specify the ATM address of the interface. atm nsap-address nsap-address
Step 3 Specify the IP address of the interface. ip address address mask2
Step 4 Identify the ATM ARP server for the IP subnetwork network and set the idle timer. atm arp-server time-out minutes3
Step 5 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.
3 When you use this form of the atm arp-server command, it indicates that this interface will perform the ATM ARP server functions. When you configure the ATM ARP client (as described earlier), the atm arp-server command is used--with a different keyword and argument--to identify a different ATM ARP server to the client.

You can designate the current router as the ATM ARP server in Step 4 by adding self before the NSAP address.

The idle timer interval is the number of minutes a destination entry listed in the ATM ARP server's ARP table can be idle before the server takes any action to time out the entry.

For an example of configuring the ATM ARP server, see the "ATM ARP Server Configuration in an SVC Environment Example (Cisco 4500 Series)" section later in this chapter.

Configure Classical IP and Inverse ARP in a PVC Environment (Cisco 4500 Series)

The ATM Inverse ARP mechanism is applicable to networks that use PVCs, where connections are established but the network addresses of the remote ends are not known. A server function is not used in this mode of operation.

In a PVC environment, configure the ATM Inverse ARP mechanism by performing the following tasks, starting in global configuration mode:

Task Command
Step 1 Specify an ATM interface and enter interface configuration mode. interface atm number1
Step 2 Create a PVC and enable Inverse ARP on it. atm pvc vcd vci aal5snap inarp minutes 2
Step 3 Enable the ATM interface. no shutdown1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 Additional options are permitted in this command, but the order of options is important. For more information about the complete atm pvc command and the order of keywords and arguments, refer to the Wide-Area Networking Command Reference.

Repeat Step 2 for each PVC you want to create.

The inarp minutes interval specifies how often Inverse ARP datagrams will be sent on this virtual circuit. The default value is 15 minutes.


Note The ATM ARP and Inverse ATM ARP mechanisms work with IP only. All other protocols require map-list command entries to operate.

For an example of configuring the ATM Inverse ARP mechanism, see the "ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 4500 Series)" section later in this chapter.

Configure Traffic Shaping for ATM SVCs on the Cisco 4500 Series

When you configure SVCs, you can define an ATM class to add support for traffic shaping on ATM SVCs. This applies a map class to an ATM interface. When an outgoing call is made by a static map client, or by a classical IP over ATM client, a map class will be determined for the call.

You must enter map-class configuration mode before you can define an ATM class. To enter map-class configuration mode and specify the ATM class for an ATM interface, perform the following tasks in global configuration mode:

Task Command
Enter map-class configuration mode, specifying a map-class name. map-class atm class-name
Specify an ATM class for an ATM interface. atm class class-name

You can specify that an SVC be established on an ATM interface using only signaled traffic parameters. When you configure strict traffic-shaping on the router ATM interface, an SVC is established only if traffic shaping can be provided for the transmit cell flow per the signaled traffic parameters. If such shaping cannot be provided, the SVC is released.

If you do not configure strict traffic-shaping on the router ATM interface, an attempt is made to establish an SVC with traffic shaping for the transmit cell flow per the signaled traffic parameters. If such shaping cannot be provided, the SVC is installed with default shaping parameters; that is, it behaves as though a PVC were created without specifying traffic parameters.

To specify that an SVC be established on an ATM interface using only signaled traffic parameters, perform the following task in interface configuration mode:

Task Command
Specify that an SVC be established on an ATM interface using only signaled traffic parameters. atm sig-traffic-shaping strict

Customize the NPM on the Cisco 4500 Series

You can customize the ATM interface on the Cisco 4500 series. The features you can customize have default values that will most likely suit your environment and probably need not be changed. However, you might need to enter configuration commands, depending upon the requirements for your system configuration and the protocols you plan to route on the interface. Perform the tasks in the following sections if you need to customize the NPM:

Configure the Rate Queue (Cisco 4500 Series)

A rate queue defines the speed at which individual virtual circuits will transmit data to the remote end. You can configure permanent rate queues, allow the software to set up dynamic rate queues, or some combination of the two. The software dynamically creates rate queues when an atm pvc command specifies a peak/average rate that does not match any user-configured rate queue. The software dynamically creates all rate queues if you have not configured any.

Use Dynamic Rate Queues (Cisco 4500 Series)

The Cisco IOS software automatically creates rate queues as necessary to satisfy the requests of atm pvc commands. The peak rate for a VCD is set to the maximum that the PLIM will allow, and the average rate is set equal to the peak rate; then a rate queue is dynamically created for the peak rate of the VCD.

If dynamic rate queues do not satisfy your traffic shaping needs, you can configure permanent rate queues.

See the "Dynamic Rate Queue Examples (Cisco 4500 Series)" section for examples of different rate queues created in response to atm pvc commands.

Configure a Permanent Rate Queue (Cisco 4500 Series)

The NPM supports up to four different peak rates. The peak rate is the maximum rate, in kilobits per second, at which a virtual circuit can transmit. Once attached to this rate queue, the virtual circuit is assumed to have its peak rate set to that of the rate queue.

You can configure each permanent rate queue independently to a portion of the overall bandwidth available on the ATM link. The combined bandwidths of all rate queues should not exceed the total bandwidth available. A warning message is displayed if you attempt to configure the combined rate queues beyond what is available to the NPM. The total bandwidth depends on the PLIM (see the "NPM ATM Interface Types" section in the "Wide-Area Networking Overview" chapter).

To set a permanent rate queue, perform the following task in interface configuration mode:

Task Command
Configure a permanent rate queue, which defines the maximum speed at which an individual virtual circuit transmits data to a remote ATM host. atm rate-queue queue-number speed

Configure MTU Size (Cisco 4500 Series)

Each interface has a default maximum packet size or maximum transmission unit (MTU) size. On the NPM, this number defaults to 4470 bytes; the maximum is 9188 bytes. The MTU can be set on a per sub-interface basis as long as the interface MTU is as large or larger than the largest sub-interface MTU. To set the maximum MTU size, perform the following task in interface configuration mode:

Task Command
Set the maximum MTU size. mtu bytes1

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

Set the PLIM Framing (Cisco 4500 Series)

The default SONET PLIM is STS-3C. To set the SONET PLIM to STM-1 or to set the PLIM framing for E3 or DS3, perform one of the following tasks in interface configuration mode:

Task Command
Set the OC-3c SONET PLIM to STM-1.
or
Set DS3 framing mode.
or
Set E3 framing mode.
atm sonet stm-1

atm framing [m23adm | cbitplcp | m23plcp]

atm framing
[g832adm | g751adm]

The default for DS3 is C-Bit ADM framing; the default for E3 is G.751 with PLCP framing.

Set Loopback Mode (Cisco 4500 Series)

To loop all packets back to the NPM instead of the network, perform the following task in interface configuration mode:

Task Command
Set loopback mode. loopback diagnostic

To loop the incoming network packets back to the network, perform the following task in interface configuration mode:

Task Command
Set line loopback mode. loopback line

Set the VCI-to-VPI Ratio (Cisco 4500 Series)

By default, the NPM supports 1024 VCIs per VPI. This value can be any power of 2 in the range from 32 to 8192. This value controls the memory allocation in the NPM to deal with the VCI table.

To set the maximum number of VCIs to support per VPI, perform the following task in interface configuration mode:

Task Command
Set the number of VCIs per VPI. atm vc-per-vp number

The product of VC* VP is fixed at 8192; the number of virtual circuits supported per virtual path will decrease in proportion to an increase in the number of virtual paths.

Set the Source of the Transmit Clock (Cisco 4500 Series)

By default, the NPM expects the ATM switch to provide transmit clocking. To specify that the NPM generate the transmit clock internally for SONET and E3 PLIM operation, perform the following task in interface configuration mode:

Task Command
Specify that the NPM generate the transmit clock internally. atm clock internal

Configure ATM Subinterfaces for SMDS Networks on the Cisco 4500 Series

An AAL defines the conversion of user information into cells. That is, it segments upper-layer information into cells at the transmitter and reassembles them at the receiver. AAL1 and AAL2 handle isochronous traffic, such as voice and video, and are not relevant to the router. AAL3/4 and AAL5 support data communications; that is, they segment and reassemble packets. Release 11.0(5) supports both AAL3/4 and AAL5 on Cisco 4500 series routers.

Our implementation of the AAL3/4 encapsulates each AAL3/4 packet in an SMDS header and trailer. This feature supports both unicast and multicast addressing, and provides subinterfaces for up to four AAL3/4 connections over the same physical interface.


Note Each
subinterface configured to support AAL3/4 is allowed only one SMDS E.164 unicast address and one E.164 multicast address. The multicast address is used for all broadcast operations. In addition, only one virtual circuit is allowed on each subinterface that is being used for AAL3/4 processing, and it must be an AAL3/4 virtual circuit.

Support for AAL3/4 on an ATM interface requires static mapping of all protocols except IP. However, dynamic routing of IP can coexist with static mapping of other protocols on the same ATM interface.

To configure an ATM interface for SMDS networks, perform the following tasks in interface configuration mode:

Task Command
Step 1 Provide an SMDS E.164 unicast address for the subinterface. atm smds-address address 
Step 2 Provide an SMDS E.164 multicast address. atm multicast address
Step 3 Create an AAL3/4 PVC. atm pvc vcd vpi vci aal34smds

Note AAL3/4 is not supported at OC-3c rates on Cisco 4500 series routers. If AAL3/4 is configured on an OC-3c interface, it must be limited to E3 or DS3 rates by setting up a permanent rate queue for the interface. See the "
Configure the Rate Queue (Cisco 4500 Series)" section.

After configuring the ATM interface for SMDS networks, configure the interface for standard protocol configurations, as needed. For more information about protocol configuration, refer to the relevant chapters of this manual.

For examples of configuring an ATM interface for AAL3/4 support, see the "PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 7000 Family)" section later in this chapter. The main differences between the Cisco 7000 AAL3/4 and the Cisco 4500 are that the aal command to enable aal3/4, the mid-per-vc command, and the vp-filter command are not used on the Cisco 4500.

Configure Transparent Bridging for ATM on the Cisco 4500 Series

Our implementation of transparent bridging over ATM on the Cisco 4500 allows the spanning tree for an interface to support virtual circuit descriptors (VCDs) for AAL5-LLC SNAP encapsulations as MAC addresses. 

If the relevant interface or subinterface is explicitly put into a bridge group, as described in the following task table, AAL5-SNAP encapsulated bridge packets on a PVC are fast-switched.

Our bridging implementation supports IEEE 802.3 frame formats and IEEE 802.10 frame formats. The router can accept IEEE 802.3 frames with or without frame check sequence (FCS). When the router receives frames with FCS (RFC 1483 bridge frame formats with 0x0001 in the PID field of the SNAP header), it strips off the FCS and forwards the frame as necessary. All IEEE 802.3 frames that originate at or are forwarded by the router are sent as 802.3 bridge frames without FCS (bridge frame formats with 0x0007 in the PID field of the SNAP header).


Note Transparent bridging for ATM on the Cisco 4500 works only on AAL5-LLC/SNAP PVCs (fast-switched). AAL3/4-SMDS, AAL5-MUX, and AAL5-NLPID
bridging are not yet supported on the Cisco 4500. Transparent bridging for ATM also does not operate in a switched virtual circuit (SVC) environment.

To configure transparent bridging for LLC/SNAP PVCs, compete the following steps beginning in interface configuration mode:

Task Command
Step 1 Specify an ATM interface and, optionally, a subinterface. interface atm number[.subinterface]1
Step 2 Assign a source IP address and subnet mask to the interface, if needed. ip address ip-address mask2
Step 3 Create one or more PVCs using AAL5-SNAP encapsulation. atm pvc vcd vpi vci aal5snap

atm pvc vcd vpi vci aal5snap

atm pvc vcd vpi vci aal5snap

Step 4 Assign the interface to a bridge group. bridge-group group3
Step 5 Return to global configuration mode. exit
Step 6 Define the type of spanning tree protocol as DEC. bridge group protocol dec3

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.
2 This command is documented in the "IP Commands" chapter in the Network Protocols Command Reference, Part 1.
3 This command is documented in the "Transparent Bridging Commands" chapter in the Bridging and IBM Networking Command Reference.

No other configuration is required. Spanning tree updates are broadcast to all AAL5-SNAP virtual circuits that exist on the ATM interface. Only the AAL5-SNAP virtual circuits on the specific subinterface receive the updates. The router does not send spanning tree updates to AAL5-MUX and AAL5-NLPID virtual circuits.

For an example of transparent bridging for an AAL5-SNAP PVC, see the "Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 4500 Series)" section.

Monitor and Maintain the ATM Interface

After configuring the new interface, you can display its status. You can also display the current state of the ATM network and connected virtual circuits. To show current virtual circuits and traffic information, perform the following tasks in EXEC mode:

Task Command
Display ATM-specific information about an ATM interface. show atm interface atm slot/0  (Cisco 7000)
or
show atm interface atm
number  (Cisco 4500)
Display the configured list of ATM static maps to remote hosts on an ATM network. show atm map
Display global traffic information to and from all ATM networks connected to the router. Display a list of counters of all ATM traffic on this router. show atm traffic
Display ATM virtual circuit information about all PVCs and SVCs (or a specific virtual circuit). show atm vc [vcd]
Display statistics for the ATM interface. show interface atm slot/01  (Cisco 7000)
or
show interface atm number1  (Cisco 4500)
Display SSCOP details for the ATM interface. show sscop

1 This command is documented in the "Interface Commands" chapter in the Configuration Fundamentals Command Reference.

ATM Access over a Serial Interface Example

The example in this section illustrates how to configure a serial interface for ATM access.

In the following example, serial interface 0 is configured for ATM-DXI with MUX encapsulation. Because MUX encapsulation is used, only one protocol is carried on the PVC. This protocol is explicitly identified by a dxi map command, which also identifies the protocol address of the remote node. This PVC can carry IP broadcast traffic.

interface serial 0
ip address 172.21.178.48
encapsulation atm-dxi
dxi pvc 10 10 mux
dxi map ip 172.21.178.4 10 10 broadcast

Cisco 7000 Family Configuration Examples

The examples in the following sections illustrate how to configure an ATM interface on the Cisco 7000 Family:

PVC with AAL5 and LLC/SNAP Encapsulation Examples (Cisco 7000 Family)

The following example creates PVC 5 on ATM interface 3/0. It uses LLC/SNAP encapsulation over AAL5. The interface is at IP address 1.1.1.1 with 1.1.1.5 at the other end of the connection. The static map list named atm declares that the next node is a broadcast point for multicast packets from IP.

interface atm 3/0
ip address 1.1.1.1 255.255.255.0
atm rate-queue 1 100
atm pvc 5 0 10 aal5snap
ip route-cache cbus
map-group atm
map-list atm
ip 1.1.1.5 atm-vc 5 broadcast

The following example is of a typical ATM configuration for a PVC:

interface atm 4/0
ip address 172.21.168.112 255.255.255.0
map-group atm
atm rate-queue 1 100
atm maxvc 512
atm pvc 1 1 1 aal5snap
atm pvc 2 2 2 aal5snap
atm pvc 6 6 6 aal5snap
atm pvc 7 7 7 aal5snap
decnet cost 1
clns router iso-igrp comet
!
router iso-igrp comet
net 47.0004.0001.0000.0c00.6666.00
!
router igrp 109
network 172.21.0.0
!
ip domain-name CISCO.COM
!
map-list atm
ip 172.21.168.110 atm-vc 1 broadcast
clns 47.0004.0001.0000.0c00.6e26.00 atm-vc 6 broadcast
decnet 10.1 atm-vc 2 broadcast

PVCs in a Fully Meshed Network Example (Cisco 7000 Family)

Figure 14 illustrates a fully meshed network. The configurations for Routers A, B, and C follow the figure. In this example, the routers are configured to use PVCs. Fully meshed indicates that any workstation can communicate with any other workstation. Note that the two map-list statements configured in Router A identify the ATM addresses of Routers B and C. The two map-list statements in Router B identify the ATM addresses of Routers A and C. The two map list statements in Router C identify the ATM addresses of Routers A and B.


Figure 14: Fully Meshed ATM Configuration Example


Router A
ip routing
!
interface atm 4/0
ip address 172.21.168.1 255.255.255.0
atm rate-queue 1 100
atm pvc 1 0 10 aal5snap
atm pvc 2 0 20 aal5snap
map-group test-a
!
map-list test-a
ip 172.21.168.2 atm-vc 1 broadcast
ip 172.21.168.3 atm-vc 2 broadcast
Router B
ip routing
!
interface atm 2/0
ip address 172.21.168.2 255.255.255.0
atm rate-queue 1 100
atm pvc 1 0 20 aal5snap
atm pvc 2 0 21 aal5snap
map-group test-b
!
map-list test-b
ip 172.21.168.1 atm-vc 1 broadcast
ip 172.21.168.3 atm-vc 2 broadcast
Router C
ip routing
!
interface atm 4/0
ip address 172.21.168.3 255.255.255.0
atm rate-queue 1 100
atm pvc 2 0 21 aal5snap
atm pvc 4 0 22 aal5snap
map-group test-c
!
map-list test-c
ip 172.21.168.1 atm-vc 2 broadcast
ip 172.21.168.2 atm-vc 4 broadcast

SVCs in a Fully Meshed Network Example (Cisco 7000 Family)

The following example is also a configuration for the fully meshed network shown in Figure 14, but this example uses SVCs. PVC 1 is the signaling PVC.

Router A
interface atm 4/0
ip address 172.21.168.1 255.255.255.0
map-group atm
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.2 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
ip 172.21.168.3 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
Router B
interface atm 2/0
ip address 172.21.168.2 255.255.255.0
map-group atm
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.1 atm-nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
ip 172.21.168.3 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
Router C
interface atm 4/0
ip address 172.21.168.3 255.255.255.0
map-group atm
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.1 atm-nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
ip 172.21.168.2 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13

SVCs with Multipoint Signaling Example (Cisco 7000 Family)

The following example configures an ATM interface for SVCs using multipoint signaling:

interface atm 2/0
 ip address 4.4.4.6
 map-group atm_pri
 atm nsap-address de.cdef.01.234567.890a.bcde.f012.3456.7890.1234.12
 atm multipoint-signaling
 atm rate-queue 1 100
 atm maxvc 1024
 atm pvc 1 0 5 qsaal
!
map-list atm_pri
! 
ip 4.4.4.4 atm-nsap cd.cdef.01.234566.890a.bcde.f012.3456.7890.1234.12 broadcast
ip 4.4.4.7 atm-nsap 31.3233.34.353637.3839.3031.3233.3435.3637.3839.30 broadcast

Classical IP and ARP Examples (Cisco 7000 Family)

This section provides three examples of classical IP and ARP configuration, one each for a client and a server in an SVC environment, and one for ATM Inverse ARP in a PVC environment.

ATM ARP Client Configuration in an SVC Environment Example (Cisco 7000 Family)

This example configures an ATM ARP client in an SVC environment. Note that the client in this example and the ATM ARP server in the next example are configured to be on the same IP network.

interface atm 2/0
atm nsap-address ac.2456.78.040000.0000.0000.0000.0000.0000.0000.00
ip address 10.0.0.2 255.0.0.0
atm pvc 1 0 5 qsaal
atm arp-server nsap ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00
no shutdown

ATM ARP Server Configuration in an SVC Environment Example (Cisco 7000 Family)

The following example configures ATM on an interface and configures the interface to function as the ATM ARP server for the IP subnetwork:

interface atm 0/0
ip address 10.0.0.1 255.0.0.0
atm nsap-address ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
atm arp-server self

ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 7000 Family)

The following example configures ATM on an interface and then configures the ATM Inverse ARP mechanism on the PVCs on the interface, with Inverse ARP datagrams sent every 5 minutes on three of the PVCs. The fourth PVC will not send Inverse ATM ARP datagrams, but will receive and respond to Inverse ATM ARP requests.

interface atm 4/0
ip address 172.21.1.111 255.255.255.0
atm pvc 1 1 1 aal5snap inarp 5
atm pvc 2 2 2 aal5snap inarp 5
atm pvc 3 3 3 aal5snap inarp 5
atm pvc 4 4 4 aal5snap inarp 

No map-group and map-list commands are needed for IP.

PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 7000 Family)

The following example provides a minimal configuration of an ATM interface to support AAL3/4 and SMDS encapsulation; no protocol configuration is shown:

interface atm3/0
atm aal aal3/4
atm smds c140.888.9999
atm vp-filter 0
atm multicast e180.0999.9999
atm pvc 30 0 30 aal34smds

The following example shows how IP dynamic routing might coexist with static routing of another protocol:

interface atm3/0
ip address 172.21.168.112 255.255.255.0
atm aal aal3/4
atm smds c140.888.9999
atm multicast e180.0999.9999
atm vp-filter 0
atm pvc 30 0 30 aal34smds
map-group atm
appletalk address 10.1
appletalk zone atm
!
map-group atm 
atalk 10.2 smds c140.8111.1111 broadcast

This example shows that IP configured is dynamically routed, but that AppleTalk is statically routed. An AppleTalk remote host is configured at address 10.2 and is associated with SMDS address c140.8111.1111.

AAL3/4 associates a protocol address with an SMDS address, as shown in the last line of this example. In contrast, AAL5 static maps associate a protocol address with a PVC number.

Dynamic Rate Queue Examples (Cisco 7000 Family)

Both of the following examples assume that no permanent rate queues have been configured. The software dynamically creates rate queues when an atm pvc command specifies a peak or average rate that does not match any user-configured rate queue.

In the following example, the software sets the peak rate for VCD 1 to the maximum that the PLIM will allow and sets the average rate to the peak rate. Then it creates a rate queue for the peak rate of this VCD.

atm pvc 1 1 1 aal5snap

In the following example, the software creates a 100-Mbps rate queue and assigns VCD 2 to that rate queue with an average rate of 50 Mbps and a burst size of 64 cells:

atm pvc 2 2 2 aal5snap 100000 50000 2

Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 7000 Family)

In the following example, three AAL5-SNAP PVCs are created on the same ATM interface. The router will broadcast all spanning tree updates to these AAL5-SNAP PVCs. No other virtual circuits will receive spanning tree updates.

interface atm4/0
ip address 1.1.1.1 255.0.0.0
atm pvc 1 1 1 aal5snap
atm pvc 2 2 2 aal5snap
atm pvc 3 3 3 aal5snap
bridge-group 1
!
bridge 1 protocol dec

Transparent Bridging on an SMDS Subinterface Example (Cisco 7000 Family)

In the following example, the router will send all spanning tree updates to the multicast address e111.1111.1111.1111. Routers receiving packets from this router will learn its unicast SMDS address, c111.1111.1111.1111, by examining the packets.

interface atm4/0
ip address 1.1.1.1 255.0.0.0
atm aal aal3/4
atm vp-filter 0
atm smds c111.1111.1111.1111
atm multicast e111.1111.1111.1111
atm pvc 1 0 1 aal34smds
bridge-group 1
!
bridge 1 protocol dec

Traffic Parameters Example (Cisco 7000 Family)

The following example defines a map list to tie specified SVCs to protocol addresses of remote hosts and to specified map classes. Then it defines the map classes and sets traffic parameters for certain protocol traffic.

map-list atmlist

 ip 131.108.170.21 atm-vc 12

 ip 131.108.180.121 atm-nsap 47.0091.81.000000.0041.0B0A.1581.0040.0B0A.1585.00 class atmclass1

 ip 131.108.190.221 atm-nsap 47.0091.81.000000.0041.0B0A.1581.0040.0B0B.1585.00 class atmclass2

 map-class atm atmclass1

 atm forward-peak-cell-rate-clp1 8000

 atm backward-peak-cell-rate-clp1 8000

 map-class atm atmclass2

 atm forward-peak-cell-rate-clp1 7000

 atm backward-peak-cell-rate-clp1 7000

 interface atm 2/0

 map-group atmlist

Cisco 4500 Series Configuration Examples

The examples in the following sections illustrate how to configure an ATM interface on the Cisco 4500 series:

PVC with AAL5 and LLC/SNAP Encapsulation Examples (Cisco 4500 Series)

The following example creates PVC 5 on ATM interface 0. It uses LLC/SNAP encapsulation over AAL5. The interface is at IP address 1.1.1.1 with 1.1.1.5 at the other end of the connection. The static map list named atm declares that the next node is a broadcast point for multicast packets from IP.

interface atm 0
ip address 1.1.1.1 255.255.255.0
atm rate-queue 1 100
atm pvc 5 0 10 aal5snap
ip route-cache cbus
map-group atm
map-list atm
ip 1.1.1.5 atm-vc 5 broadcast

The following example is of a typical ATM configuration for a PVC:

interface atm 0
ip address 172.21.168.112 255.255.255.0
map-group atm
atm rate-queue 1 100
atm pvc 1 1 1 aal5snap
atm pvc 2 2 2 aal5snap
atm pvc 6 6 6 aal5snap
atm pvc 7 7 7 aal5snap
decnet cost 1
clns router iso-igrp comet
!
router iso-igrp comet
net 47.0004.0001.0000.0c00.6666.00
!
router igrp 109
network 172.21.0.0
!
ip domain-name CISCO.COM
!
map-list atm
ip 172.21.168.110 atm-vc 1 broadcast
clns 47.0004.0001.0000.0c00.6e26.00 atm-vc 6 broadcast
decnet 10.1 atm-vc 2 broadcast

PVCs in a Fully Meshed Network Example (Cisco 4500)

Figure 15 illustrates a fully meshed network. The configurations for Routers A, B, and C follow the figure. In this example, the routers are configured to use PVCs. Fully meshed indicates that any workstation can communicate with any other workstation. Note that the two map-list statements configured in Router A identify the ATM addresses of Routers B and C. The two map-list statements in Router B identify the ATM addresses of Routers A and C. The two map list statements in Router C identify the ATM addresses of Routers A and B.


Figure 15: Fully Meshed ATM Configuration Example


Router A
ip routing
!
interface atm 0
ip address 172.21.168.1 255.255.255.0
atm rate-queue 1 100
atm pvc 1 0 10 aal5snap
atm pvc 2 0 20 aal5snap
map-group test-a
!
map-list test-a
ip 172.21.168.2 atm-vc 1 broadcast
ip 172.21.168.3 atm-vc 2 broadcast
Router B
ip routing
!
interface atm 0
ip address 172.21.168.2 255.255.255.0
atm rate-queue 1 100
atm pvc 1 0 20 aal5snap
atm pvc 2 0 21 aal5snap
map-group test-b
!
map-list test-b
ip 172.21.168.1 atm-vc 1 broadcast
ip 172.21.168.3 atm-vc 2 broadcast
Router C
ip routing
!
interface atm 0
ip address 172.21.168.3 255.255.255.0
atm rate-queue 1 100
atm pvc 2 0 21 aal5snap
atm pvc 4 0 22 aal5snap
map-group test-c
!
map-list test-c
ip 172.21.168.1 atm-vc 2 broadcast
ip 172.21.168.2 atm-vc 4 broadcast

SVCs in a Fully Meshed Network Example (Cisco 4500 Series)

The following example is also a configuration for the fully meshed network shown in Figure 15, but this example uses SVCs. PVC 1 is the signaling PVC.

Router A
interface atm 0
ip address 172.21.168.1 255.255.255.0
map-group atm
atm nsap-address AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.2 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
ip 172.21.168.3 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
Router B
interface atm 0
ip address 172.21.168.2 255.255.255.0
map-group atm
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13
atm rate-queue 1 100
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.1 atm-nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
ip 172.21.168.3 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
Router C
interface atm 0
ip address 172.21.168.3 255.255.255.0
map-group atm
atm nsap-address BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1224.12
atm rate-queue 1 100
atm pvc 1 0 5 qsaal
!
map-list atm
ip 172.21.168.1 atm-nsap AB.CDEF.01.234567.890A.BCDE.F012.3456.7890.1234.12
ip 172.21.168.2 atm-nsap BC.CDEF.01.234567.890A.BCDE.F012.3456.7890.1334.13

Classical IP and ARP Examples (Cisco 4500 Series)

This section provides three examples of classical IP and ARP configuration, one each for a client and a server in an SVC environment, and one for ATM Inverse ARP in a PVC environment.

ATM ARP Client Configuration in an SVC Environment Example (Cisco 4500 Series)

This example configures an ATM ARP client in an SVC environment. Note that the client in this example and the ATM ARP server in the next example are configured to be on the same IP network.

interface atm 0
atm nsap-address ac.2456.78.040000.0000.0000.0000.0000.0000.0000.00
ip address 10.0.0.2 255.0.0.0
atm pvc 1 0 5 qsaal
atm arp-server nsap ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00
no shutdown

ATM ARP Server Configuration in an SVC Environment Example (Cisco 4500 Series)

The following example configures ATM on an interface and configures the interface to function as the ATM ARP server for the IP subnetwork:

interface atm 0
ip address 10.0.0.1 255.0.0.0
atm nsap-address ac.1533.66.020000.0000.0000.0000.0000.0000.0000.00
atm rate-queue 1 100
atm maxvc 1024
atm pvc 1 0 5 qsaal
atm arp-server

ATM Inverse ARP Configuration in a PVC Environment Example (Cisco 4500 Series)

The following example configures ATM on an interface and then configures the ATM Inverse ARP mechanism on the PVCs on the interface, with Inverse ARP datagrams sent every 5 minutes on three of the PVCs. The fourth PVC will not send Inverse ATM ARP datagrams, but will receive and respond to Inverse ATM ARP requests.

interface atm 0
ip address 172.21.1.111 255.255.255.0
atm pvc 1 1 1 aal5snap inarp 5
atm pvc 2 2 2 aal5snap inarp 5
atm pvc 3 3 3 aal5snap inarp 5
atm pvc 4 4 4 aal5snap inarp 

No map-group and map-list commands are needed for IP.

Dynamic Rate Queue Examples (Cisco 4500 Series)

Both of the following examples assume that no permanent rate queues have been configured. The software dynamically creates rate queues when an atm pvc command specifies a peak/average rate that does not match any user-configured rate queue.

In the following example, the software sets the peak rate for VCD 1 to the maximum that the PLIM will allow and sets the average rate to the peak rate. Then it creates a rate queue for the peak rate of this VCD.

atm pvc 1 1 1 aal5snap

In the following example, the software creates a 100-Mbps rate queue and assigns VCD 2 to that rate queue with an average rate of 50 Mbps and a burst size of 64 cells:

atm pvc 2 2 2 aal5snap 100000 50000 2

PVC with AAL3/4 and SMDS Encapsulation Examples (Cisco 4500 Series)

The following example provides a minimal configuration of an ATM interface to support AAL3/4 and SMDS encapsulation; no protocol configuration is shown:

interface atm0
atm smds c140.888.9999
atm multicast e180.0999.9999
atm pvc 30 0 30 aal34smds

The following example shows how IP dynamic routing might coexist with static routing of another protocol.

interface atm0
ip address 172.21.168.112 255.255.255.0
atm smds c140.888.9999
atm multicast e180.0999.9999
atm pvc 30 0 30 aal34smds
map-group atm
appletalk address 10.1
appletalk zone atm
!
map-group atm 
atalk 10.2 smds c140.8111.1111 broadcast

This example shows that IP configured is dynamically routed, but that AppleTalk is statically routed. An AppleTalk remote host is configured at address 10.2 and is associated with SMDS address c140.8111.1111.

AAL3/4 associates a protocol address with an SMDS address, as shown in the last line of this example. In contrast, AAL5 static maps associate a protocol address with a PVC number.

Transparent Bridging on an AAL5-SNAP PVC Example (Cisco 4500 Series)

In the following example, three AAL5-SNAP PVCs are created on the same ATM interface. The router will broadcast all spanning tree updates to these AAL5-SNAP PVCs. No other virtual circuits will receive spanning tree updates.

interface atm 0
ip address 1.1.1.1 255.0.0.0
atm pvc 1 1 1 aal5snap
atm pvc 2 2 2 aal5snap
atm pvc 3 3 3 aal5snap
bridge-group 1
!
bridge 1 protocol dec

Traffic Parameters Example (Cisco 4500 Series)

The following example defines a map list to tie specified SVCs to protocol addresses of remote hosts and to specified map classes. Then it defines the map classes and sets traffic parameters for certain protocol traffic.

map-list atmlist

 ip 131.108.170.21 atm-vc 12

 ip 131.108.180.121 atm-nsap 47.0091.81.000000.0041.0B0A.1581.0040.0B0A.1585.00 class atmclass1

 ip 131.108.190.221 atm-nsap 47.0091.81.000000.0041.0B0A.1581.0040.0B0B.1585.00 class atmclass2

 map-class atm atmclass1

 atm forward-peak-cell-rate-clp1 8000

 atm backward-peak-cell-rate-clp1 8000

 map-class atm atmclass2

 atm forward-peak-cell-rate-clp1 7000

 atm backward-peak-cell-rate-clp1 7000

 interface atm 0

 map-group atmlist


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