January 7, 1999
These release notes describe new features for the Cisco uBR904 cable modem that supports Cisco IOS Release 12.0(2)XC. Cisco IOS Release 12.0(2)XC is based on Cisco IOS Release 12.0. These release notes are updated with each maintenance release of the Cisco IOS software, which is typically every 6 weeks.
Use these release notes in conjunction with the Release Notes for Cisco IOS Release 12.0 and the Release Notes for Cisco uBR7200 Series for Cisco IOS Release 12.0 XC located on Cisco Connection Online (CCO) and the Documentation CD-ROM.
For a list of software caveats that apply to Release 12.0(2)XC and previous releases, refer to the "Caveats" section. Refer also to the Caveats for Cisco IOS Release 12.0 T located on CCO and the Documentation CD-ROM.
These release notes discuss the following topics:
The Cisco uBR904 cable modem is part of a new class of Cisco data-over-cable products. The Cisco uBR904 cable modem is also referred to as a subscriber unit, a key component within a cable data system. This subscriber unit functions as an interface between the subscriber's personal computer and the cable operator's network within the subscriber's small office or home office.
The Cisco uBR904 cable modem is a compact, easy-to-install device that can receive and transmit digital data over a hybrid fiber-coaxial (HFC) network; the same cable that brings television broadcast transmissions into a cable television (CATV) subscriber's home. With a Cisco uBR904 cable modem, a personal computer can be connected to the HFC cable network for high-speed access to the Internet. The link that enables the transmission of two-way digital data from the HFC network to the Internet is provided by the Cisco uBR7246 universal broadband router installed at the cable headend.
The Cisco uBR904 cable modem is based on the Multimedia Cable Network System (MCNS) Partners, Ltd. Data-Over-Cable Service Interface Specification (DOCSIS) standards. MCNS is a consortium of cable television companies whose goal is to create standards for interoperable data-over-cable systems.
This release notes document is based on the Cisco uBR904 for Cisco IOS Release 12.0(2)XC. Release 12.0(2)XC is an Early Deployment (ED) release, delivering both fixes to software caveats and support for new Cisco hardware. The following table briefly describes some of the ED releases that will be available for the Cisco uBR904.
|ED Release||Maintenance Release||Additional Software Features||Additional Hardware Features||Additional Software Images||Availability|
Release 12.0 XC
Easy IP, DOCSIS Privacy
IPSec 56, L2TP, DOCSIS Privacy
Easy IP, IPSec 56, L2TP, DOCSIS Privacy
This section describes the system requirements for Release 12.0(2)XC and includes the following sections:
Table 2 describes the memory requirements for the feature sets supported by Cisco uBR904 cable modem for Cisco IOS Release 12.0(2)XC.
|Feature Set||Image Name||Required|
|IP Routing Standard Feature Sets|
Standard Home Office, Easy IP
4 MB Flash
8 MB DRAM
Added in Release 12.0(2)XC
Standard Home Office, Easy IP, DOCSIS Privacy
4 MB Flash
8 MB DRAM
Encryption image added in Release 12.0(2)XC
Telecommuter (Basic), IPSec 56, L2TP, DOCSIS Privacy
4 MB Flash
8 MB DRAM
Encryption image added in Release 12.0(2)XC
Small Office, Easy IP, IPSec 56, L2TP, DOCSIS Privacy
4 MB Flash
8 MB DRAM
Encryption image added in Release 12.0(2)XC
Cisco IOS Release 12.0(2)XC supports the following new hardware features:
For detailed descriptions of the new hardware features refer to the "New and Changed Information" section.
Cisco IOS Release 12.0(2)XC also supports the available MC11 and MC16 cable line cards:
For more information on the MC11 and MC16 cable line card software, refer to the "New and Changed Information" section.
To determine the version of Cisco IOS software running on your Cisco uBR904 cable modem, log into the Cisco uBR904 cable modem and enter the show version user EXEC command, this Cisco IOS version appears in the second line:
router> show version Cisco Internetwork Operating System Software IOS (tm) 904 Software (UBR900-y5-mz), Version 12.0(2)XC...
Additional command output lines include more information, such as processor revision numbers, memory amounts, hardware IDs, and partition information.
At the time of this printing, no product bulletins are available for upgrading to Cisco IOS Release 12.0(2)XC. For generic information on updating to a new software release, refer to the Cisco IOS Software Release Upgrade Paths and Packaging Simplification product bulletin located on CCO. On CCO, follow this path:
Products & Ordering: More Information: Product Bulletins
Scroll to Software. Under Cisco IOS 11.3, click Cisco IOS Software Release 11.3 Upgrade Paths (#703: 12/97). The Cisco IOS Software Release Upgrade Paths and Packaging Simplification product bulletin does not contain information specific to Cisco IOS Release 12.0(2)XC, but provides generic upgrade information that might apply to Cisco IOS Release 12.0(2)XC.
Cisco IOS software is packaged in feature sets (also called software images) depending on the platform. Each feature set contains a specific set of Cisco IOS features. The following sections list the feature set matrix and the features supported by each feature set.
Table 3 lists the Cisco IOS software feature sets available for the Cisco uBR904 in Cisco IOS Release 12.0(2)XC. Table 3 lists the feature set name, the software image name, the platform, and whether the feature set is available with additional functionality.
|Feature Set||Feature Set Matrix Term||Software Image||Platforms|
Standard Home Office
Easy IP, DOCSIS Privacy
Standard Home Office
IPSec 56, L2TP, DOCSIS Privacy
Easy IP, IPSec 56, L2TP, DOCSIS Privacy
|Caution Cisco IOS images with strong encryption (including, but not limited to, 56-bit data encryption feature sets) are subject to U.S. government export controls, and have a limited distribution. Images to be installed outside the U.S. require an export license. Customer orders might be denied or subject to delay due to U.S. government regulations. Contact your sales representative or distributor for more information, or send e-mail to email@example.com.|
Table 4 lists the features and feature sets supported by Cisco IOS Release 12.0(2)XC for the Cisco uBR904 cable modem. Table 4 uses the following conventions to identify features:
|Feature||In1||Easy IP||Easy IP, DOCSIS Privacy||IPSec 56, L2TP, DOCSIS Privacy||Easy IP, IPSec 56, L2TP, DOCSIS Privacy|
Cable Device MIB
Cisco Standard MIBs
Full and MCNS-compliant Bridging
Network Address Translation and Port Address Translation (NAT/PAT), DHCP Server
Radio Frequency Interface (RFI) MIB
Routing (RIP V2)
|1This column indicates the maintenance release in which the feature was introduced in 12.0 XC. For example, (2) means a feature is introduced in 12.0(2)XC. If a cell in this column is empty, the feature was included in the initial base release.|
The following sections list the new features supported by the Cisco uBR904 in Cisco IOS Release 12.0(2)XC. These features and others may have been introduced initially in Cisco IOS Release 11.3(4)NA. For more information on the features for the Cisco uBR904, refer to the Release Notes for Cisco uBR904 Cable Modem for Cisco IOS Release 11.3 NA document located on CCO.
The following hardware enhancements were introduced and are available in Cisco IOS Release 12.0(2)XC.
For more information refer to the Release Notes for Cisco IOS Release 12.0.
Cisco uBR7246 universal broadband features enable the Cisco uBR7200 universal broadband router to communicate with a hybrid fiber-coaxial (HFC) cable network via a Cisco MC11 cable modem card. Cisco MC11 cable modem cards allow you to connect cable modems on the HFC network to a Cisco uBR7246 in a Community Antenna Television (CATV) headend facility. The modem card provides the interface between the Cisco uBR7246 protocol control information (PCI) bus and the radio frequency (RF) signal on the HFC network.
The Cisco uBR7223 is part of a new class of Cisco data-over-cable products designed to allow two-way transmission of digital data over hybrid fiber-coaxial (HFC) cable. The Cisco uBR7223 supports IP routing with a wide variety of protocols and any combination of Ethernet, Fast Ethernet, High-Speed Serial Interface (HSSI), serial, Packet-Over-SONET (POS), and Asynchronous Transfer Mode (ATM) media.
The Cable Router Line Card (MC16) is available for the Cisco uBR7200. The software for the MC16 card is a driver running on the Cisco uBR7246. Using a PCI interface, the universal broadband router line card software interacts with the MC16 card. Data is passed back and forth, as direct memory access (DMA) transfers, from the Cisco uBR7246 memory to the MC16 card.
Additionally, the MC16 card supports universal broadband router line card management and control with the MC16 MIB, MAC control software and logical link management software based on MCNS standards, and minimized security.
For more information refer to the Update to the Cisco uBR7200 Series Cable Modem Card Installation and Configuration for the MC16A EFT Card publication.
Cisco uBR904 Cable Modem
The Cisco uBR904 cable modem is the subscriber unit, a key component within a cable data system. This subscriber unit functions as an interface between the subscriber's personal computer and the cable operator's network within the subscriber's small office or home office.
The Cisco uBR904 cable modem has four Ethernet (10BaseT) ports and supports the Multimedia Cable Network System (MCNS) cable interface. The MCNS cable interface ensures interoperability between the Cisco uBR904 cable modem and other devices within a system operator's infrastructure. MCNS requires the cable interface to be configured automatically and defines mechanisms for all of the cable parameters to be obtained. For this reason, no new cable interface configuration commands will need to be configured during normal operation.
For more information on the hardware supported for Cisco IOS Release 12.0(2)XC, refer to the Release Notes for Cisco uBR7200 Series for Cisco IOS Release 12.0 XC document located on CCO.
With the introduction of Easy IP, Cisco IOS Release 12.0(2)XC supports Intelligent DHCP Relay and DHCP Client functionality. A DHCP Relay Agent is any host that forwards DHCP packets between clients and servers. A DHCP Relay Agent enables the client and server to reside on separate subnets. If the Cisco IOS DHCP server cannot satisfy a DHCP request from its own database, it can forward the DHCP request to one or more secondary DHCP servers defined by the network administrator using standard Cisco IOS IP helper-address functionality.
Easy IP also supports NAT/PAT functionality. Network Address Translation (NAT) allows customers to maintain their own private networks while giving them full Internet access through the use of one or more global IP addresses. NAT address overloading allows several private IP addresses to use the same global IP address. NAT facilitates configuration and permits a larger network of users to access the network using one Cisco uBR904 cable modem and the same MCNS cable interface IP address.
NAT eliminates the need to readdress all hosts with existing private network address (one-to-one translation) or by enabling all internal hosts to share a single registered IP address (many-to-one translation, also known as Port Address Translation [PAT]).
IPSec is an IP security feature that provides robust authentications and encryption of IP packets. IPSec is a framework of open standards developed by the Internet Engineering Task Force (IETF). IPSec provides security for transmission of sensitive information over unprotected networks such as the Internet. IPSec acts at the network layer, protecting and authenticating IP packets between participating IPSec devices ("peers") such as Cisco routers.
IPSec provides the following network security services:
With IPSec, data can be transmitted across a public network without fear of observation, modification, or spoofing. This enables applications such as virtual private networks (VPNs), extranets, and remote user access.
IPSec services are similar to those provided by Cisco Encryption Technology, a proprietary security solution introduced in Cisco IOS Software Release 11.2. However, IPSec provides a more robust security solution, and is standards-based.
Layer Two Tunneling Protocol (L2TP) is an emerging Internet Engineering Task Force (IETF) standard that combines the best features of two existing tunneling protocols: Cisco's Layer Two Forwarding (L2F) and Microsoft's Point-to-Point Tunneling Protocol (PPTP). L2TP is an extension to the Point-to-Point Protocol (PPP), which is an important component for Access Virtual Private Networks (VPNs). Access VPNs allow mobile users to connect to their corporate intranets or extranets, thus improving flexibility and reducing costs.
Traditional dial-up networking services only supported registered IP addresses, which limited the types of applications that could be implemented over Virtual Private Networks (VPNs). L2TP supports multiple protocols and unregistered and privately administered IP addresses over the Internet. This allows the existing access infrastructure, such as the Internet, modems, access servers, and ISDN terminal adapters (TAs), to be used.
L2TP can be initiated wherever PPTP or L2F is currently deployed and can be operated as a client initiated tunnel, such as PPTP, or a network access server (NAS) initiated tunnel, such as L2F.
Refer to the "Limitations and Restrictions" section for information regarding the functionality of the Cisco uBR904 cable modem in L2TP applications.
The DOCSIS Privacy feature is based on the DOCSIS Baseline Privacy Interface Specification. It provides data privacy across the HFC network by encrypting traffic flows between the uBR904 and the cable operator's cable modem termination system (CMTS).
Baseline Privacy security services are defined as a set of extended services within the MCNS MAC sublayer. Two new MAC management message types, BPKM-REQ and BPKM-RSP are employed to support the Baseline Privacy Key Management (BPKM) protocol.
The BPKM protocol does not use authentication mechanisms such as passwords or digital signatures; it provides basic protection of service by ensuring that a cable modem, uniquely identified by its 48-bit IEEE MAC address, can only obtain keying material for services it is authorized to access. The Cisco uBR904 is able to obtain two types of keys from the CMTS: the Traffic Exchange Key (TEK), which is used to encrypt and decrypt data packets, and the Key Exchange Key (KEK), which is used to the decrypt the TEK.
For more information on this feature, refer to the DOCSIS Baseline Privacy Interface Specification (SP-BPI-IO1-970922).
This section describes warnings and cautions about using Cisco IOS Release 12.0(2)XC software.
The current implementation of L2TP in Cisco IOS Release 12.0(2)XC is dependent on a PPP connection supported on one of the directly attached interfaces. A dialup PPP connection is required in order to initiate an L2TP Tunnel connection. This is a requirement of the L2TP Access Concentrator (LAC). In Cisco IOS Release 12.0(2)XC, the Cisco uBR904 cable modem cannot function as the LAC; it can only function as the L2TP Network Server (LNS), which terminates a tunnel created elsewhere in the network.
This section contains important information about use of your Cisco IOS Release 12.0(2) XC software.
Older Cisco Management Information Bases (MIBs) will be replaced in a future release. OLD-CISCO-* MIBS are currently being migrated into more scalable MIBs, without affecting existing Cisco IOS products or NMS applications. Application developers should update from deprecated MIBs to the replacement MIBs as shown in the table below.
(Compilation of other OLD* MIBS)
This section contains open and resolved caveats for the current Cisco IOS maintenance release only.
Caveats in Cisco IOS Release 12.0 also apply to Release 12.0 T. For information on caveats in Cisco IOS Release 12.0, refer to the "Caveats" section in the Cross-Platform Release Notes for Cisco IOS Release 12.0 document located on CCO and the Documentation CD-ROM. This section contains caveats affecting all maintenance releases.
This section describes possibly unexpected behavior by Release 12.0(2)XC. Unless otherwise noted, these caveats apply to all 12.0 releases up to and including 12.0(2)XC
Description: If a User Datagram Protocol (UDP) packet with an invalid length is sent to port 514 (the "syslog" port) on an IOS device, the device is likely to reload. In this situation, a stack trace might not be saved. Such packets are sent by the popular nmap port scanning program.
Workaround: You can work around this vulnerability by preventing any affected Cisco IOS device from receiving or processing UDP datagrams addressed to its port 514. This can be done either using packet filtering on surrounding devices, or by using input access list filtering on the affected IOS device itself.
If you use an input access list, that list should be applied to all interfaces to which attackers may be able to send datagrams. This includes not only physical LAN and WAN interfaces, but virtual subinterfaces of those physical interfaces, as well as virtual interfaces and/or interface templates corresponding to GRE, L2TP, L2F, and other tunnelling protocols.
The input access list must block traffic destined for any of the Cisco IOS device's own IP addresses, as well as for any broadcast or multicast addresses on which the Cisco IOS device may be listening. It's important to remember to block old-style "all-zeroes" broadcasts as well as new-style "all-ones" broadcasts.
There is no single input access list that will work in all configurations. It is very important that you understand the effect of your access list in your specific configuration before you activate the list.
The following example shows a possible access list for a three-interface router, along with the configuration commands needed to apply that access list. The example assumes no need for input filtering other than as a workaround for this vulnerability.
! Deny all multicasts, and all unspecified-net broadcasts, to port 514 access-list 101 deny udp any 126.96.36.199 188.8.131.52 eq 514 ! Deny old-style unspecified-net broadcasts access-list 101 deny udp any host 0.0.0.0 eq 514 ! Deny network-specific broadcasts. This example assumes that all of ! the local interfaces are on the class B network 172.16.0.0, subnetted ! everywhere with mask 255.255.255.0. This will differ from network ! to network. Note that we block both new-style and old-style broadcasts. access-list 101 deny udp any 172.16.0.255 0.0.255.0 eq 514 access-list 101 deny udp any 172.16.0.0 0.0.255.0 eq 514 ! Deny packets sent to the addresses of our own network interfaces. access-list 101 deny udp any host 172.16.1.1 eq 514 access-list 101 deny udp any host 172.16.2.1 eq 514 access-list 101 deny udp any host 172.16.3.3 eq 514 ! Permit all other traffic (default would be to deny) access-list 101 permit ip any any
! Apply the access list to the input side of each interface interface ethernet 0 ip address 172.16.1.1 255.255.255.0 ip access-group 101 in interface ethernet 2 ip address 172.16.2.1 255.255.255.0 ip access-group 101 in
interface ethernet 3 ip address 172.16.3.3 255.255.255.0 ip access-group 101 in
It can be complicated to list all possible addresses, and especially all possible broadcast addresses, to which attack packets might be sent. If you do not expect to receive any legitimate syslog traffic on an interface, you may wish to simply block all syslog traffic arriving on that interface. Remember that this will affect traffic routed through the Cisco IOS device as well as traffic destined to the device.
Input access lists have an impact on system performance, and should be installed with a degree of caution, especially on systems that are running very near their capacity limits.
Description: When you configure Bisync (encapsulation bstun) with the ASCII character set (bsc char-set ascii) on the first port of a serial WIC (1T, 2T, or 2A/S) in WIC slot 0 of a Cisco 2600 series router, only the first character of each frame is received, and the BSTUN tunnel is not established.
Symptoms: This only affects Bisync mode when it is configured with the ASCII character set. Other encapsulations are not affected, and using the EBCDIC character set with Bisync works correctly.
Details: For the first serial port in WIC slot 0, the parity detection is not configured correctly for Bisync in ASCII mode. The first character of each frame generates a parity error that causes the receiver to discard the frame after the first character received.
Workaround: Use a different serial port: either the second serial port (port 1) on a 2T or 2A/S WIC in WIC slot 0 or any serial port in WIC slot 1. If you have only one serial WIC, moving it from WIC slot 0 to WIC slot 1 fixes this problem.
Because Cisco IOS Release 12.0(2)XC is a limited-time release, only the initial caveats are documented in these release notes.
The following sections describe the documentation available for the Cisco uBR900 series cable modems and related documents. Typically, these documents consist of hardware installation guides, software installation guides, Cisco IOS configuration and command references, system error messages, and feature modules, which are updates to the Cisco IOS documentation. Documentation is available as printed manuals or electronic documents, except for feature modules, which are available online only.
The most up-to-date documentation can be found on the Web via Cisco Connection Online (CCO) and the Documentation CD-ROM. These electronic documents might contain updates and modification made after the hard copy documents were printed.
These release notes should be used in conjunction with the documents listed in this section.
The following documents are specific to Release 12.0. They are located on CCO and the Documentation CD-ROM:
Software & Support: Cisco Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.0: Release Notes: Cross-Platform Release Notes for Cisco IOS Release 12.0
Cisco IOS Software Configuration: Cisco IOS Release 12.0: Release Notes: Cross-Platform Release Notes for Cisco IOS Release 12.0
Software & Support: Software Center: Cisco IOS Software
Feature modules describe new features supported by Release 12.0(2)XC, and are an update to the Cisco IOS documentation set. As updates, the features modules are available online only. The feature module information is included in the next printing of the Cisco IOS documentation set. Each feature module consists of a brief overview of the feature, benefits, configuration tasks, and a command reference.
To reach the feature modules on CCO, follow this path:
Products & Ordering: Cisco Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.0: New Feature Documentation: New Features in 12.0-Based Limited Lifetime Releases: New Features in Release 12.0 XC: New Features in Release 12.0(2)XC
To reach the feature modules on the Documentation CD-ROM, follow this path:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.0: New Feature Documentation: New Features in 12.0-Based Limited Lifetime Releases: New Features in Release 12.0 XC: New Features in Release 12.0(2)XC
The following documents are available for the Cisco uBR904. These documents are also available on CCO and the Documentation CD-ROM.
To reach Cisco uBR904 documentation on CCO, follow this path:
Software & Support: Documentation: Cisco Documentation: Cisco Product Documentation: Broadband/Cable Solutions: Cisco uBR904 Cable Modem
To reach Cisco uBR904 documentation on the Documentation CD-ROM, follow this path:
Broadband/Cable Solutions: Cisco uBR904 Cable Modem
The Cisco IOS software documentation set consists of the Cisco IOS configuration guides, Cisco IOS command references, and several other supporting documents. These documents are shipped with your order in electronic form on the Documentation CD-ROM, unless you specifically ordered the printed versions.
Each module in the Cisco IOS documentation set consists of two books: a configuration guide and a corresponding command reference. Chapters in a configuration guide describe protocols, configuration tasks, and Cisco IOS software functionality and contain comprehensive configuration examples. Chapters in a command reference provide complete command syntax information. Each configuration guide can be used in conjunction with its corresponding command reference.
On CCO and the Documentation CD-ROM, two master hot-linked documents provide information for the Cisco IOS software documentation set: configuration guides and command references.
To reach these documents on CCO, follow this path:
Products & Ordering: Cisco Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.0: Configuration Guides and Command References: Cisco IOS Interface Configuration Guide or Cisco IOS Interface Command Reference
To reach these documents on the Documentation CD-ROM, follow this path:
Cisco IOS Software Configuration: Cisco IOS Release 12.0: Configuration Guides and Command References: Cisco IOS Interface Configuration Guide or Cisco IOS Interface Command Reference
Table 6 details the contents of the Cisco IOS Release 12.0 software documentation set. The document set is available in electronic form, and also in printed form upon request.
To reach the Cisco IOS documentation set on CCO, follow this path:
Products & Ordering: Cisco Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.0: Configuration Guides and Command References
To reach the Cisco IOS documentation set on the Documentation CD-ROM, follow this path:
Cisco IOS Software Configuration: Cisco IOS Release 12.0: Configuration Guides and Command References
Configuration Fundamentals Overview
Dial-In Port Setup
Interface Configuration Overview
AAA Security Services
Switching Paths for IP Networks
Voice over IP
|1This book will not be available until January 1999.|
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