Table Of Contents
Release Notes for Cisco uBR905 Cable Access Router for Cisco IOS Release 12.2 XA
July 2, 2001
These release notes for the Cisco uBR905 Cable Access Router describe the enhancements provided in Cisco IOS Release 12.2(2)XA. These release notes are updated as needed to describe new features, memory requirements, hardware support, software platform deferrals, and changes to the microcode or modem code and related documents.
For a list of software caveats that apply to Release 12.2(2)XA, see the "Caveats" section and Caveats for Cisco IOS Release 12.2 T. The caveats document is updated for every maintenance release and is located on Cisco Connection Online (CCO) and the Documentation CD-ROM.
Use these release notes with Cross-Platform Release Notes for Cisco IOS Release 12.2 located on CCO and the Documentation CD-ROM. For complete documentation on the Cisco uBR905 Cable Access Router, see the documentation listed in the "Related Documentation" section.
These release notes describe the following topics:
The DOCSIS-based Cisco uBR905 cable access router gives small office, home office (SOHO) and branch office subscribers high-speed Internet or intranet access. The Cisco uBR905 cable access router supports data traffic via a shared two-way cable system and IP backbone network. The Cisco uBR905 cable access router connects computers and other customer premises devices at a subscriber site to the service provider cable, hybrid fiber-coaxial (HFC), and IP backbone network.
The Cisco uBR905 cable access router is based on Data-over-Cable Service Interface Specifications (DOCSIS) and interoperates with any bidirectional, DOCSIS-qualified cable modem termination system (CMTS). The Cisco uBR905 cable access router ships from the Cisco factory with a Cisco IOS software image stored in nonvolatile Flash memory that supports DOCSIS-compliant bridging data operations. The Cisco uBR905 cable access router functions as a cable modem at the subscriber site to convey data communications on the cable television system.
Based on the feature licenses your company purchased, other Cisco IOS images can be downloaded from Cisco.com. Special operating modes, based on your service offering and the practices in place for your network, can be supported for the Cisco uBR905 router, based on the available images in Cisco IOS Release 12.2(2)XA. The Cisco uBR905 cable access router can also function as an advanced router, providing WAN data connectivity in a variety of configurations.
Note All Cisco uBR905 cable access router images support DOCSIS Baseline Privacy Interface (BPI) encryption. BPI is subject to export restrictions.
Cisco uBR905 Cable Access Router
The Cisco uBR905 cable access router features a single F-connector interface to the cable system, four RJ-45 (10BASE-T Ethernet) hub ports, and one RJ-45 console port to connect to a laptop computer/console terminal for local Cisco IOS configuration. The Cisco uBR905 cable access router also provides an onboard IPSec hardware accelerator, which provides high-performance encryption that is substantially faster than software-based encryption.
Early Deployment Releases
These release notes describe the Cisco uBR905 Cable Access Router for Cisco IOS Release 12.2(2)XA, which is an early deployment (ED) release based on Cisco IOS Release 12.2 T. Early deployment releases contain fixes for software caveats and support for new Cisco hardware and software features.
Table 1 shows that Release 12.2(2)XA is the initial early deployment release of the Cisco uBR905 Cable Access Router:
Table 1 Early Deployment Releases for the Cisco uBR905 Cable Access Router
ED Release Additional Software Features Availability
•Cable Monitor Web Diagnostics Tool
•Cisco Firewall (Phases I and II)—Cisco IOS Firewall Software
•Cisco Secure Intrusion Detection System (IDS) (formerly known as NetRanger) support
•DOCSIS 1.0+ Extensions—Dynamic Multi-SID1 Assignment and Concatenation
•DOCSIS Baseline Privacy Interface (BPI)
•Dynamic Host Configuration Protocol (DHCP) Proxy Support
•Enhanced bridging functionality
•Full and DOCSIS-compliant bridging
•IPSec—56-bit encryption/decryption at network layer (Phase I)
•IPSec 3DES—Triple DES4 (Phase I): 168-bit encryption/decryption at network layer (Phase I)
•IPSec Hardware Accelerator—onboard encryption hardware accelerator is automatically used by default for all IPSec encryption
•L2TP—Layer 2 tunneling protocol (Phase I)
•Network address translation and port address translation (NAT/PAT)
•Radio frequency interface
•Routing (RIP V2)
•Secure Shell (SSH) Version 1 Client and Server Support
•Support for the ip address dhcp command
•VPN6 Enhancements—Dynamic Crypto Map
1 SID = Service ID
2 HSRP = Hot-Standby Routing Protocol
3 ICMP = Internet Control Message Protocol
4 DES = Data Encryption Standard
5 MIB = Management Information Base
6 VPN = Virtual Private Network
This section describes the system requirements for Cisco IOS Release 12.2(2)XA and includes the following sections:
Table 2 lists the minimum memory recommendations for Cisco IOS Release 12.2(2)XA for the Cisco uBR905 cable access router.
If DOCSIS concatenation with a 16-QAM (quadrature amplitude modulation) symbol rate is used, the CMTS must be configured for Unique Word 16 in the preamble for both short and long data burst profiles. On the Cisco uBR7200 series universal broadband routers, use the cable modulation-profile global configuration command and specify "uw16" for both the long and short modulation profiles.
DOCSIS 1.0+ Extensions
Cisco IOS Release 12.1 XL images support the Cisco DOCSIS 1.0+ Extensions, which include dynamic multi-SID assignment and concatenation. To use the dynamic multi-SID and concatenation features, the Cisco uBR905 router and the CMTS router must support them. If you are using the Cisco uBR7200 series headend equipment as the CMTS router, Cisco IOS Release 12.1(1)T or a later release is required on the CMTS router to ensure that these features are activated.
To configure the Cisco uBR905 cable access router to support multiple classes of service, use either the Cisco Subscriber Registration Center (CSRC) tool or the configuration file editor of your choice. DOCSIS configuration files can contain multiple classes of service (CoS) to support voice and other real-time traffic. The first CoS is used for data (and voice if no other CoS is defined), and up to three additional classes of service can be defined to give higher priority for voice and other real-time traffic.
IPSec Encryption Support
To use IPSec encryption, the Cisco uBR905 cable access router and the destination endpoint must support IPSec encryption and be configured for the same encryption policy. The endpoint is typically an IPSec gateway such as a peer router, Cisco PIX Firewall, or other device that can be configured for IPSec. (The CMTS need not support IPSec encryption unless it is desired that the CMTS act as an IPSec gateway.)
Note The IPSec feature set encrypts traffic sent between endpoints, such as between two Cisco uBR905 cable access routers, to protect traffic sent across the Internet and other unprotected networks. The DOCSIS BPI feature encrypts traffic on the cable interface between the Cisco uBR905 cable access router and the CMTS. To use BPI encryption, the Cisco uBR905 cable access router and the CMTS must support and enable BPI encryption.
The Cisco uBR905 cable access router contains the following interfaces:
•A single F-connector interface to the cable system.
•Four RJ-45 (10BASE-T Ethernet) hub ports to connect:
•Up to three computers directly to the four Ethernet hub ports at the rear of the Cisco uBR905 router when operating in bridging mode. When operating in routing mode, all four Ethernet hub ports can be connected directly to four computers.
•One of the four Ethernet hub ports at the rear of the Cisco uBR905 router can be connected to an Ethernet hub, which then connects additional computers or devices at the site when operating in routing or bridging mode.
•One RJ-45 console port (optional) to connect to a laptop computer or console terminal when locally configuring the Cisco uBR905 router; the router ships from the Cisco factory with the console port enabled.
•The onboard hardware accelerator for IPSec encryption is automatically used by default to encrypt and decrypt all traffic protected by either 56-bit or 168-bit IPSec encryption.
Determining the Software Version
To determine the version of Cisco IOS software running on your cable access router, log into the cable access router and enter the show version EXEC command:
For the cable access router:router# show versionCisco Internetwork Operating System SoftwareIOS (tm) 920 Software (ubr925-k8o3sv4y5-mz), Version 12.2(2)XA, RELEASE SOFTWARE
Upgrading to a New Software Release
For technical information about upgrading to a new software release, see Cisco IOS Upgrade Ordering Instructions on Cisco.com located at:
Service & Support: Software Center: Cisco IOS Software: Product Bulletins: Software
Feature Set Tables
Cisco IOS software is packaged in feature sets consisting of software images, depending on the platform. Each feature set contains a specific set of Cisco IOS features.
Caution Cisco IOS images with strong encryption (including, but not limited to, 168-bit [3DES] data encryption feature sets) are subject to United States government export controls and have limited distribution. Strong encryption images to be installed outside the United States may require an export license. Customer orders may be denied or subject to delay due to United States government regulations. When applicable, the purchaser/user must obtain local import and use authorizations for all encryption strengths. Contact your sales representative or distributor for more information, or send an e-mail to firstname.lastname@example.org.
Table 3 lists the features and feature sets supported by the Cisco uBR905 cable access router in Cisco IOS Release 12.2(2)XA and uses the following conventions:
Yes—The feature is supported in the software image.
No—The feature is not supported in the software image.
In—The number in the "In" column indicates the Cisco IOS release in which the feature was introduced. For example, (2) means a feature was introduced in 12.2(2)XA. If a cell in this column is empty, the feature was included in the initial base release.
Note This table might not be cumulative or list all the features in each image. You can find the most current Cisco IOS documentation on Cisco.com.
This set of electronic documents may contain updates and modifications made after the hard-copy documents were printed. If you have a Cisco.com login account, you can find image and release information regarding features prior to Cisco IOS Release 12.2(2)XA by using the Feature Navigator tool at http://www.cisco.com/go/fn.
New and Changed Information
New Hardware Features in Release 12.2(2)XA
There are no new hardware features in Cisco IOS Release 12.2(2)XA for the Cisco uBR905 cable access router.
New Software Features in Release 12.2(2)XA
The following new software features are supported by the Cisco uBR905 Cable Access Router for Release 12.2(2)XA.
Cable Monitor Web Diagnostics Tool
The Cable Monitor is a web-based diagnostic tool to display the current status and configuration of the Cisco uBR905 router. The Cable Monitor can also be used when the cable network is down, providing an easy way for subscribers to provide necessary information to service technicians and troubleshooters.
Cisco IOS Firewall (Phase I and II)
The Cisco IOS Firewall feature set includes the following set of features:
•Context-Based Access Control (CBAC) that intelligently filters TCP and UDP packets based on the application-layer protocol. This includes Java applets, which can be blocked completely or allowed only from known and trusted sources.
•Detection and prevention of the most common denial of service (DoS) attacks, such as ICMP and UDP echo packet flooding, SYN packet flooding, half-open or other unusual TCP connections, and deliberate misfragmentation of IP packets.
•Support for a broad range of commonly used protocols, including H.323 and NetMeeting, FTP, HTTP, MS Netshow, RPC, SMTP, SQL*Net, and TFTP.
•Authentication Proxy for authentication and authorization of web clients on a per-user basis.
•Dynamic port mapping that maps the default port numbers for well-known applications to other port numbers. This can be done on a host-by-host basis or for an entire subnet, providing a large degree of control over which users can access different applications.
•Configurable alerts and audit trail.
•Intrusion Detection System (IDS) that recognizes the signatures of 59 common attack profiles. When an intrusion is detected, IDS can either send an alarm to a syslog server or to NetRanger Director, drop the packet, or reset the TCP connection.
•User-configurable audit rules.
•Configurable real-time alerts and audit trail logs.
For general information, see the description of the Cisco IOS Firewall Feature Set in the Cisco Product Catalog. For detailed information, see the Cisco IOS Firewall Feature Set documentation set, as well as the section Traffic Filtering and Firewalls in the Security Configuration Guide and the Security Command Reference (available on the Documentation CD-ROM and CCO).
Cisco Secure Intrusion Detection System (IDS) Support
Cisco IOS Release 12.2(2)XA supports the Cisco Secure Intrusion Detection System (IDS), formerly known as Cisco NetRanger, which is composed of three parts:
•A management console (director) that is used to view the alarms and to manage the sensors.
•A sensor that monitors traffic. This traffic is matched against a list of known signatures to detect misuse of the network. This is usually in the form of scanning for vulnerabilities or of attacking systems. When a signature is matched, the sensor can track certain actions. In the case of the appliance sensor, it can reset the sessions (using the TCP/rst calls), or enable "shuns" of further traffic. In the case of the IOS-IDS, it can drop traffic. In all cases, the sensor can send alarms to the director.
•Communications through automated report generation of standardized and customizable reports and QoS/CoS monitoring capabilities.
DOCSIS 1.0+ Extensions
In addition to the other quality of service (QoS) features, DOCSIS 1.1 supports a number of features that are required for the delivery of high-quality voice traffic. To use these features before the DOCSIS 1.1 specification is finalized, Cisco has created the DOCSIS 1.0+ extensions that contain the most important of these features:
•Concatenation—DOCSIS concatenation combines multiple upstream packets into one packet to reduce packet overhead and overall latency, and to increase transmission efficiency. Using concatenation, a DOCSIS cable modem makes only one bandwidth request for multiple packets, as opposed to making a different bandwidth request for each individual packet; this technique is especially effective for bursty real-time traffic, such as voice calls.
•Dynamic Multi-SID Assignment—To give priority to voice traffic, the Cisco uBR905 router assigns a different SID to each voice port. Without the DOCSIS 1.0+ extensions, the router creates these SIDs during the provisioning process, and the SIDs remain in effect until the router is rebooted with a different configuration. As part of this process, a minimum guaranteed bandwidth is permanently allocated to the voice ports; this bandwidth is reserved to the voice ports even if no calls are being made.
To avoid potentially wasting bandwidth in this manner, the DOCSIS 1.0+ extensions support the dynamic creation of multiple SIDs. New Media Access Control (MAC) messages dynamically add, delete, and modify SIDs when needed. When a phone connected to the router is taken off-hook, the Cisco uBR905 router creates a SID that has the QoS parameters needed for that particular voice call. When the call terminates, the router deletes the SID, releasing its bandwidth for use elsewhere.
The DOCSIS 1.0+ features are introduced in Cisco IOS Software Release 12.0(7) XR and 12.1(1) T.
Note Both the Cisco uBR905 Cable Access Router and the CMTS must support the dynamic multi-SID and concatenation features for them to be used on the cable network. If you are using the Cisco uBR7200 series universal broadband router as the CMTS, Cisco IOS Release 12.1(1) T (or later) is required on the Cisco uBR7200 series routers to use these features.
DOCSIS Baseline Privacy Interface (BPI)
The DOCSIS Baseline Privacy Interface (BPI) feature is based on the DOCSIS BPI Specification (SP-BPI-I02-990319 or later revision). It provides data privacy across the Hybrid Fiber-Coaxial (HFC) network by encrypting traffic flows between the Cisco uBR905 Cable Access Router and the cable operator's CMTS.
The BPI+ (BPI Plus) feature is an enhancement to the BPI feature and is based on the DOCSIS BPI+ Specification (SP-BPI+-I04-000407 or later revision), which is still in development. In addition to the regular BPI features, BPI+ provides more secure authentication of cable modems through the use of digital certificates. Also, a cable modem can use a digital signature to verify that the software image it has downloaded has not been altered or corrupted in transit.
Note Cisco IOS Release 12.2(2)XA supports BPI encryption but not BPI+ encryption. The CMTS and Cisco uBR905 Cable Access Router must both support and enable BPI to use its features.
DOCSIS Baseline Privacy Management Information Base
The Baseline Privacy Management Information Base (MIB), as currently defined, is available in Cisco IOS Release 12.2(2)XA code. BPI allows a Simple Network Management Protocol (SNMP) manager to monitor and manage the Cisco uBR905 Cable Access Router's BPI configuration, including whether BPI is enabled, status of current authorization keys, current timeout values, real-time status counters, and additional information about authorization errors.
Note The SNMP manager must load the DOCSIS-BPI-MIB.my MIB to access the BPI attributes. See the "Cable-Specific MIBs" section for details.
Dynamic Host Configuration Protocol Proxy Support
The DHCP Proxy Support feature helps to automate the configuration of the Cisco uBR905 Cable Access Router in two situations:
•When the Cisco uBR905 Cable Access Router is configured for routing mode, an IP address must be assigned to its Ethernet interface. The DHCP Proxy Support feature allows an external DHCP server to assign an IP address to the Ethernet interface, as opposed to having to assign it manually with the appropriate command line interface (CLI) commands.
•When network address translation (NAT) is used, an inside global address pool must be created on the Ethernet interface. The DHCP Proxy Support feature allows a DHCP server to assign an IP address that automatically creates the NAT address pool, as opposed to manually specifying a static IP address with the appropriate command line interface (CLI) commands.
When configured for DHCP Proxy Support, during startup the Cisco uBR905 Cable Access Router sends a proxy DHCP request to the DHCP server using the Ethernet interface's MAC address. The DHCP server replies with a second IP address that the router assigns to either the Ethernet interface or to the NAT pool, depending on which option was specified.
Easy IP—DHCP Server and NAT/PAT
The Easy IP feature set includes the following features to automate the assignment and use of IP addresses:
•The DHCP server feature on the Cisco uBR905 Cable Access Router includes both Intelligent DHCP Relay and DHCP Client functionality. A DHCP Relay Agent is any host that forwards DHCP packets between clients and servers—this enables the client and server to reside on separate subnets. If the Cisco uBR905 Cable Access Router DHCP server cannot satisfy a DHCP request from its own database, it can act as a DHCP proxy agent by forwarding the DHCP request to one or more secondary DHCP servers.
•Network address translation (NAT) and port address translation (PAT) frees a private network from needing a worldwide unique IP address for every computer connected to the Internet. Instead, the Cisco uBR905 Cable Access Router translates the IP addresses used on the private network into a global IP address that can be used on the Internet. One IP address can be used for multiple computers because a unique port address identifies the individual computers on the private network.
The Cisco uBR905 Cable Access Router contains four RJ-45 (10BaseT Ethernet) hub ports, which can be connected to four computers directly or one of the four ports to an Ethernet hub. The Ethernet hub connects additional computers or devices at the site. A maximum of 254 devices can be bridged in DOCSIS bridging mode; no limit exists in routing mode.
Full and DOCSIS-Compliant Bridging
DOCSIS-compliant bridging allows the Cisco uBR905 Cable Access Router to operate as a DOCSIS 1.0 cable modem, so that it can interoperate with any DOCSIS-qualified CMTS. This is the default mode of operation for the Cisco uBR905 Cable Access Router.
HSRP Support for ICMP Redirects (CSCdp37610)
The HSRP Support for ICMP Redirects feature enables Internet Control Message Protocol (ICMP) redirection on interfaces configured with the Hot Standby Router Protocol.
When running HSRP, it is important to prevent hosts from discovering the interface (or real) MAC addresses of routers in the HSRP group. If a host is redirected by ICMP to the real MAC address of a router, and that router later fails, then packets from the host will be lost. Previously, ICMP redirect messages were automatically disabled on interfaces configured with HSRP.
This feature now enables ICMP redirects on interfaces configured with HSRP. This functionality works by filtering outgoing ICMP redirect messages through HSRP, where the next-hop IP address may be changed to an HSRP virtual IP address.
IP Address Negotiation
The Cisco uBR905 Cable Access Router supports the ip address dhcp command on the cable interface. Older Cisco IOS releases used the ip address negotiated command for this purpose, but this command is now reserved for serial interfaces.
IPSec Encryption (56-bit and 3DES)
IPSec Network Security (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 the Cisco uBR905 Cable Access Router.
IPSec provides the following network security services:
•Privacy—IPSec can encrypt packets before transmitting them across a network.
•Integrity—IPSec authenticates packets at the destination peer to ensure that the data has not been altered during transmission.
•Authentication—Peers authenticate the source of all IPSec-protected packets.
•Anti-replay protection—Prevents capture and replay of packets; helps protect against denial-of-service attacks.
•3DES—Triple DES (3DES) images increase the encryption/decryption from the 56-bit IPSec feature set to 168 bits.
Layer 2 Tunneling Protocol
Layer 2 Tunneling Protocol (L2TP) is an emerging Internet Engineering Task Force (IETF) standard that combines Cisco's Layer 2 Forwarding (L2F) and Microsoft's Point-to-Point Tunneling Protocol (PPTP). L2TP is an extension of the Point-to-Point Protocol (PPP), which is an important component for Access Virtual Private Networks (VPNs).
Traditional dial-up networking services only supported registered IP addresses, which limited the types of applications that could be implemented over 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.
Note Cisco IOS Release 12.2(2)XA1, 12.2(2)T, or greater is required to support Generic routing encapsulation (GRE) IP tunnels.
Management Information Base (MIB) Features
Cisco IOS Release 12.2(2)XA supports the following MIB features:
•Baseline Privacy Interface (BPI) MIBs
•Cable Device MIBs
•Cisco Standard MIBs
•Radio Frequency Interface MIBs
RFC 2233 Support
In Cisco IOS Release 12.2(2)XA, the IF-MIB MIB supports RFC 2233, which obsoletes the previous RFC 1573. This change adds the "ifCounterDiscontinuityTime" attribute and changes the "ifTableLastChange attribute."
In addition, this feature adds support for RFC 2233-compliant link up and link down traps. By default, link up and link down traps are implemented as given in the CISCO-IF-CAPABILITY.my MIB. To generate link up and link down traps as defined by RFC 2233, use the snmp-server trap link ietf global configuration command.
Routing (RIP V2)
When configured for routing mode, the Cisco uBR905 Cable Access Router supports the Routing Information Protocol Version 2 (RIPv2). In routing mode the Cisco uBR905 Cable Access Router automatically configures itself to use the headend's IP address as its IP default gateway. This allows the Cisco uBR905 Cable Access Router to send packets not intended for the private LAN to the headend for delivery to the Internet and other networks.
Note The Cisco uBR905 Cable Access Router supports only static routes and the RIP routing protocol.
Secure Shell Version 1 Client Support
The Secure Shell (SSH) protocol provides for authentication and encryption at the application layer, providing a secure connection even when BPI or IPSec authentication and encryption are not used at the network layer.
By default, the SSH feature uses 56-bit DES encryption. Higher security 168-bit 3DES encryption is available when using Cisco IOS images that support 3DES IPSec encryption. (The SSH client must also support the same level of encryption.)
In Cisco IOS Release 12.2(2)XA, SSH support includes the following features:
•SSH server support allows users to use an SSH connection to log in to the Cisco uBR905 router.
•SSH client support allows a user logged in to the Cisco uBR905 Cable Access Router to log in to another router using SSH authentication and encryption.
•DES and 3DES encryption are supported, depending on the capabilities of the Cisco IOS image being used.
•RSA authentication. (RSA stands for Rivest, Shamir, and Adelman, inventors of a public-key cryptographic system.)
Note For configuration and other information, see the Secure Shell Version 1 Client feature module, available on CCO and the Documentation CD-ROM.
Cisco IOS Release 12.2(2)XA supports RFC 2669 and RFC 2670 for the DOCS-CABLE-DEVICE-MIB and DOCS-IF-MIB MIBs, respectively.
VPN Enhancement—Dynamic Crypto Map
Dynamic crypto map is one of the Cisco PIX IPSec network security commands. IPSec provides security for transmission of sensitive information over unprotected networks such as the Internet.
The dynamic crypto map command is used to create policy templates that are used when processing negotiation requests for new security associations from a remote IPSec peer, even if you do not know all of the crypto map parameters required to communicate with the remote peer (such as the peer's IP address). The dynamic crypto map allows you to accept requests for new security associations from previously unknown peers. These requests, however, are not processed until the Internet Security Association and Key Management Protocol (ISAKMP) Internet Key Exchange (IKE) authentication has completed successfully.
When the firewall receives a negotiation request via IKE from another IPSec peer, the request is examined to see if it matches a crypto map entry. If the negotiation does not match any explicit crypto map entry, it will be rejected unless the crypto map set includes a reference to a dynamic crypto map.
If the firewall accepts the peer's request, at the point that it installs the new IPSec security associations, it also installs a temporary crypto map entry. This entry is filled in with the results of the negotiation. At this point, the firewall performs normal processing, using this temporary crypto map entry as a normal entry, even requesting new security associations if the current ones are expiring (based on the policy specified in the temporary crypto map entry). After all of the corresponding security associations expire, the temporary crypto map entry is removed.
Dynamic crypto map sets are not used for initiating IPSec security associations. However, they are used for determining whether traffic should be protected.
Note The only parameter required in a dynamic crypto map command is the set transform-set. All other parameters are optional.
Limitations and Restrictions
Cisco IOS Release 12.2 T for the Cisco uBR905 cable access router contains the following limitations and restrictions.
The Cisco uBR905 cable access router interoperates with DOCSIS cable networks. Cisco IOS Release 12.2(1)T does not support bridging traffic across a non-DOCSIS cable network.
DOCSIS CLI Commands are Removed
To comply with DOCSIS requirements that restrict access to commands that change DOCSIS parameters, Cisco IOS Release 12.2(1)T has removed a number of commands from the CLI. The following commands and their no formare now reserved exclusively for DOCSIS use:
•cable-modem downstream saved channel
•cable-modem downstream symbol rate
•cable-modem upstream preamble qpsk
GRE IP Tunnels Support
Cisco IOS Release 12.2(2)XA1, 12.2(2)T, or greater is required to support Generic routing encapsulation (GRE) IP tunnels.
IP Address Negotiation
The DOCSIS specifications require that a cable modem obtain its IP address at power-on or reset from a DHCP server that is available through the cable interface.
For this reason, the Cisco uBR905 cable access router defaults to a configuration that uses the ip address dhcp command for the cable interface. It is not possible to override this setting by specifying a static IP address; to assign a static IP address to the Cisco uBR905 router, configure the DHCP server so that it assigns the desired IP address on the basis of the unit MAC address.
Note The ip address negotiated command cannot be used on the cable interface because this command is reserved exclusively for the serial interface.
However, in Cisco IOS Release 12.2(1)T when the ip address dhcp command is used for cable interfaces, the configuration files still show the ip address negotiated command, which can generate an "invalid input" error during boot. This is only a cosmetic issue and does not affect the functionality of the unit.
Upgrading Software Images Using BPI
To enable BPI encryption, the Cisco uBR905 cable access router must use a Cisco IOS image that supports BPI encryption. If the current software image of the router does not support BPI encryption (or if the current software image is corrupted), you must disable BPI encryption in the DOCSIS configuration file and reset the router before you will be able to download a new software image.
Using Access Lists 100 and 101
Access lists 100 and 101 are reserved for DOCSIS use and should never be configured manually on the Cisco uBR905 cable access router. Use access lists 102 through 199 instead.
Using Multiple PCs with the Cisco uBR905 Cable Access Router
The "MAX CPE" parameter in a Cisco uBR905 cable access router DOCSIS configuration file determines how many PCs (or other CPE devices) are supported by the Cisco uBR905 cable access router. The default value for the "MAX CPE" parameter is 1, which means only one PC can be connected to the Cisco uBR905 cable access router.
The DOCSIS 1.0 specification states that a CMTS cannot age-out MAC addresses for CPE devices, so the first PC that is connected to the Cisco uBR905 cable access router is normally the only one that the CMTS recognizes as valid. If a subscriber replaces an existing PC or changes its network interface card (NIC) to one that has a different MAC address, the CMTS will refuse to let the PC come online because the maximum number of CPE devices specified by the "MAX CPE" parameter would be exceeded. The CMTS will also refuse to let the PC come online if a user decides to move a PC from one Cisco uBR905 router to another.
To allow a subscriber to replace an existing PC or NIC, the following workarounds are possible:
•If using a Cisco uBR7200 series router as the CMTS, enter the clear cable host MAC address command on the Cisco uBR7200 series router to remove the MAC address from the internal address tables of the router from the PC. The new PC will be rediscovered and associated with the correct Cisco uBR905 cable access router during the next DHCP lease cycle.
•Increase the value of the "MAX CPE" parameter in the Cisco uBR905 cable access router's DOCSIS configuration file so that it can accommodate the desired number of PCs. Reset the Cisco uBR905 cable access router to force it to load the new configuration file.
Using the Reset Switch
The reset switch on the back panel of the Cisco uBR905 Cable Access Router is recessed to prevent accidental resets of the router. To depress the switch, use a blunt object, such as a pen or pencil point; do not use a sharp object, such as a knife or awl, because sharp objects could damage the switch and the circuitry of the router.
This section contains important information about using the Cisco uBR905 cable access router with Cisco IOS Release 12.2(2)XA software.
Limitation on Vendor-Specific Information in the DOCSIS Configuration File
DOCSIS requires that when the cable modem sends its Registration Request (REG-REQ) message to the CMTS, it must include the configuration information found in the DOCSIS configuration file. This configuration information must include all vendor-specific information fields (VSIF). Because MAC-layer management messages, such as REG-REQ, have a maximum data size of 1522 bytes, this limits the amount of VSIF information that can be included in the DOCSIS configuration file.
In particular, the maximum packet size imposes a limit on the number of Cisco IOS CLI commands you can include as VSIF fields in the DOCSIS configuration file. The exact number of commands that will fit depends on the other information included in the file, as well as the length of each command.
If the REG-REQ message is larger than 1522 bytes, the cable modem will likely report errors similar to the following errors that appears on Cisco uBR900 series cable access routers:%LINK-4-TOOBIG: Interface cable-modem0, Output packet size of 1545 bytes too big%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to down
In addition, the CMTS will also report that the cable modem timed out during the registration process. If this occurs, you can try the following steps:
•Reduce the length of the commands by using the abbreviated form of the command. For example, you can specify the int c0 instead of the full command interface cable-modem0.
•SNMP MIB objects are not included in the Registration Request message, so wherever possible, replace the CLI commands with the corresponding SNMP MIB object statements in the DOCSIS configuration file.
•If a large number of CLI commands must be given, use VSIF option 128 to download a Cisco IOS configuration file to the cable modem.
For complete details on what is included in the REG-REQ message, see Chapter 6 of the current DOCSIS 1.1 specification (SP-RFIv1.1-I07-010829 or later).
Note This limitation is being tracked by caveat CSCdv83892 but is not expected to be resolved unless the DOCSIS specification is changed to remove the maximum size limit for MAC-layer management messages.
Cisco DOCSIS CPE Configurator Support
The DOCSIS specification requires that every cable modem download a DOCSIS configuration file before being allowed online. To support the creation of such files, Cisco has made available the Cisco DOCSIS CPE Configurator tool, a Java-based tool available for both Windows and Solaris systems.
Because of ongoing changes in the DOCSIS specification, you must use version 3.5 or greater of the Cisco DOCSIS CPE Configurator tool when generating DOCSIS configuration files for the Cisco uBR905 Cable Access Router. The current version of this tool is available on Cisco.com at http://www.cisco.com/cgi-bin/tablebuild.pl/cpe-conf.
CPE Device Filtering
In Cisco IOS Release 12.2(2)XA and later releases, the "docsDevCpeIpMax" attribute defaults to -1 instead of the default of 1, which was used in previous releases. This attribute controls the maximum number of CPE devices that can pass traffic through the router from its Ethernet interface as follows:
When "docsDevCpeIpMax" is set to -1, the Cisco uBR905 cable access router does not filter any IP packets on the basis of their IP addresses, and CPE IP addresses are not added to the "docsDevFilterCpeTable" table.
When "docsDevCpeIpMax" is set to 0, the Cisco uBR905 cable access router does not filter any IP packets on the basis of the IP addresses. However, the source IP addresses are still entered into the "docsDevFilterCpeTable" table.
When "docsDevCpeIpMax" is set to a positive integer, it specifies the maximum number of IP addresses that can be entered into the "docsDevFilterCpeTable" table. The Cisco uBR905 cable access router compares the source IP address for packets it receives from CPE devices to the addresses in this table. If a match is found, the packet is processed; otherwise, the packet is dropped.
CPE IP address filtering is done as part of the following process:
1. MAC address filtering—Packets are filtered on the basis of the MAC address for the CPE device. The filter is controlled by the value of the "MAX CPE" parameter, which is set in the DOCSIS configuration file.
2. Logical Link Control (LLC) filtering—Packets are filtered on the basis of the protocol for the packets. The filter is controlled by the "docsDevFilterLLCTable" table.
3. CPE IP address filtering—Packets are filtered on the basis of the IP address for the CPE device, as controlled by the "docsDevCpeIpMax" attribute and the "docsDevFilterCpeTable" table.
4. Access list filtering—Packets are filtered on the basis of access lists. IP filtering is controlled by the "docsDevFilterIpTable" table, and SNMP access filters are controlled by the "docsDevNmAccessTable" table.
See the DOCS-CABLE-DEVICE-MIB.my MIB for more information on the attributes and tables listed.
Disabling the Finger Server
By default, the Cisco uBR900 series cable access router enables its onboard TCP/IP "finger" server to allow remote users to query the number and identities of any users that are logged in to the router. Unless your network operations center (NOC) requires this service, it should be disabled to prevent denial of service attacks that access the well-known port (TCP port 79) of the finger server. To disable the finger server, include the no service finger command in the Cisco IOS configuration file that the router downloads at initial power-on.
The Cisco uBR905 cable access router supports the following categories of MIBs:
•Cable device MIBs—These MIBs are for DOCSIS-compliant cable modems and CMTS to record statistics related to the configuration and status of the cable modem. These MIBs include support for the MIB attributes defined in RFC 2669.
•Cisco standard MIBs—These MIBs are common across most of the Cisco router platforms. If your network management applications are already configured to support other Cisco routers, such as the Cisco 2600 series or Cisco 7200 series, no further configuration is needed unless the version of Cisco IOS software being used has updated these MIBs.
•Radio Frequency Interface MIBs—These MIBs are for DOCSIS-compliant radio frequency interfaces in cable modems and CMTS. This MIB includes support for the MIB attributes defined in RFC 2670.
•SNMP standard MIBs—These are the MIBs required by any agent supporting SNMPv1 or SNMPv2 network management.
•Cable-specific MIBs—These MIBs provide information about the cable interface and related information on the Cisco uBR905 cable access router. They include both DOCSIS-required MIBs and Cisco-specific enterprise MIBs. If your network management applications have not already been configured for the Cisco uBR905 cable access router, these MIBs must be loaded.
•Deprecated MIBs—These MIBs were supported in earlier releases of Cisco IOS software but have been replaced by more standardized, scalable MIBs. Network management applications and scripts should convert to the replacement MIBs as soon as possible.
Cable Device MIBs
The Cisco uBR905 cable access router supports the Cable Device MIB, which is defined by RFC 2669 and describes DOCSIS-compliant cable modems and CMTS. The Cable Device MIB records statistics related to the configuration and status of the cable modem. Statistics include an events log and device status. The following list details the components of the Cable Device MIB:
•docsDevBase group extends the MIB-II "system" group with objects needed for cable device system management.
•docsDevNmAccess group provides a minimum level of SNMP access security.
•docsDevSoftware group provides information for network downloadable software upgrades.
•docsDevServer group provides information about the progress of interaction with various provisioning servers.
•docsDevEvent group provides information about the progress of reporting.
•docsDevFilter group configures filters at the link layer and IP layer for bridge data traffic.
The Cable Device MIB is very similar to the Radio Frequency Interface (RFI) MIB in that both allow access to statistics; they are different in that the Cable Device MIB reports statistics on the cable modem, and the RFI MIB reports statistics on the radio frequency transmissions over the cable television line.
Cisco Standard MIBs
The Cisco uBR905 cable access router supports the Cisco Standard MIBs, which consist of the following components:
•IF-MIB (RFC 2233)
Note The Cisco Management Information Base (MIB) User Quick Reference publication is no longer published. For the latest list of MIBs supported by Cisco, see the Cisco Network Management Toolkit on Cisco.com. From the Cisco.com home page, click this path: Service & Support: Software Center: Network Mgmt Products: Cisco Network Management Toolkit: Cisco MIB.
Radio Frequency Interface MIBs
The Cisco uBR905 cable access router supports the Radio Frequency Interface (RFI) MIB. The RFI MIB module is defined in RFC 2670 and describes DOCSIS-compliant radio frequency interfaces in cable modems and CMTS. On the cable modem, RFI MIB entries provide the following features:
•Upstream and downstream channel characteristics
•Physical signal quality of the downstream channels
•Attributes of cable access router MAC interface
•Status of several MAC-layer counters
The RFI MIB includes tables describing both the CMTS and the cable modem side of the cable interface. All cable modem tables are implemented.
With IPSec, data can be sent across a public network without fear of observation, modification, or spoofing. IPSec enables applications such as VPNs, extranets, and remote user access.
IPSec services are similar to those provided by Cisco Encryption Technology, a proprietary Cisco security solution. However, IPSec provides a more robust security solution, and is standards based.
Table 4 shows the cable-specific MIBs that are supported on the Cisco uBR905 cable access router. This table also provides a brief description of each of the MIBcontents and the Cisco IOS software release in which the MIB was initially functional—earlier releases might have had unsupported prototype versions of the MIB; later releases might have added new attributes and functionality.
Note The names given in Table 4 are the filenames for the MIBs as they exist on the Cisco FTP site (ftp://ftp.cisco.com/pub/mibs/ or http://www.cisco.com/public/mibs /index.htm). Most MIBs are available in both SNMPv1 and SNMPv2 versions; the SNMPv1 versions have V1SMI as part of their filenames. Also refer to the Cisco MIBs home page at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
Note Because of interdependencies, the MIBs must be loaded in the order given in the table.
A number of Cisco-provided MIBs have been replaced with more scalable, standardized MIBs; these MIBs have filenames that start with "OLD" and first appeared in Cisco IOS Release 10.2. The functionality of these MIBs has already been incorporated into replacement MIBs, but the old MIBs are still present to support existing Cisco IOS products or network management system (NMS) applications. However, because the deprecated MIBs will be removed from support, you should update your network management applications and scripts to refer to the table names and attributes that are found in the replacement MIBs.
Table 5 shows the deprecated MIBs and their replacements. In most cases, SNMPv1 and SNMPv2 replacements are available, but some MIBs are available only in one version. A few of the deprecated MIBs do not have replacement MIBs; support for these MIBs will be discontinued in a future release of Cisco IOS software.
Note Some of the MIBs listed in Table 5 represent feature sets that are not supported on the Cisco uBR905 cable access router.
Caveats describe unexpected behavior in Cisco IOS software releases. Severity 1 caveats are the most serious caveats; severity 2 caveats are less serious. Severity 3 caveats are moderate caveats.
This section contains open and resolved caveats for Cisco IOS Release 12.2(2)XA. All caveats in Release 12.2 T are also in Release 12.2(2)XA.
For information on caveats in Cisco IOS Release 12.1 T, see Caveats for
Cisco IOS Release 12.1 T, which lists severity 1 and 2 caveats and selected severity 3 caveats, and is located on Cisco.com and the Documentation CD-ROM.
To access this location, you must have an account on Cisco.com. For information about how to obtain an account, go to the "Feature Navigator" section.
Note If you have an account with Cisco.com, you can use Bug Navigator II to find caveats of any severity for any release. To reach Bug Navigator II, go to Cisco.com and press Login. Then go to Software Center: Cisco IOS Software: Cisco Bugtool Navigator II. Another option is to go to http://www.cisco.com/support/bugtools/.
Note This document lists the caveats that were known at the time of publication. The Bug Navigator II site has the most current information about any caveat. Also, this document may be updated as needed with any new information about caveats; the most current version is always posted on Cisco.com.
Open Caveats—Release 12.2(2)XA
This section documents possible unexpected behavior by Cisco IOS Release 12.2(2)XA, and describes only severity 1 and 2 caveats and select severity 3 caveats.
Closed or Resolved Caveats—Release 12.2(2)XA
The following sections describe the documentation available for the cable access router. These documents consist of hardware and software installation guides, Cisco IOS configuration guides and command references, system error messages, feature modules, and other documents.
Most documentation is available as printed manuals or electronic documents, except for feature modules and select manuals, which are available online on Cisco.com and the Documentation CD-ROM.
Use these release notes with these documents:
The following documents are specific to Release 12.2 and are located on Cisco.com and the Documentation CD-ROM:
On Cisco.com at:
Technical Documents: Documentation Home Page: Cisco IOS Software Configuration: Cisco IOS Release 12.2: Release Notes: Cross-Platform Release Notes
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.2: Release Notes: Cross-Platform Release Notes
•Product bulletins, field notices, and other release-specific documents on Cisco.com at:
As a supplement to the caveats listed in these release notes, see Caveats for Cisco IOS Release 12.2, which contains caveats applicable to all platforms for all maintenance releases of Release 12.2.
On Cisco.com at:
Technical Documents: Documentation Home Page: Cisco IOS Software Configuration: Cisco IOS Release 12.2: Release Notes: Caveats
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS 12.2: Caveats
Note If you have an account with Cisco.com, you can use Bug Navigator II to find caveats of any severity for any release. To reach Bug Navigator II, go to Cisco.com and press Login. Then go to Software Center: Cisco IOS Software: Cisco Bugtool Navigator II. Another option is to go to http://www.cisco.com/support/bugtools/bugtool.shtml.
These documents are available for the Cisco uBR905 Cable Access Router on CCO and the Documentation CD-ROM:
•Cisco uBR905 Hardware Installation Guide
•Cisco uBR905 Software Configuration Guide
•Cisco uBR905 Cable Access Router Subscriber Setup Quick Start Card
•Cisco uBR905 - Release Notes for Cisco IOS Release 12.1(3a)XL
Note The Cisco uBR905 Cable Access Router Installation and Configuration Guide is still available on CCO but has been obsoleted by the hardware and software guides listed above.
On CCO at:
Technical Documents: Documentation Home Page: Cisco Product Documentation: Broadband/Cable Solutions: Cisco uBR900 Series Cable Access Routers
On the Documentation CD-ROM at:
Cisco Product Documentation: Broadband/Cable Solutions: Cisco uBR900 Series Cable Access Routers
Feature modules describe new features supported by Release 12.1, and are updates to the Cisco IOS documentation set. A feature module consists of a brief overview of the feature, benefits, and configuration tasks, and a command reference. As updates, the feature modules are available online only. Feature module information is incorporated in the next printing of the Cisco IOS documentation set.
On Cisco.com at:
Technical Documents: Documentation Home Page: Cisco IOS Software Configuration: Cisco IOS Release 12.2: New Feature Documentation
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.2: New Feature Documentation
Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a particular set of features and which features are supported in a particular Cisco IOS image.
Feature Navigator is available 24 hours a day, 7 days a week. To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, e-mail the Contact Database Administration group at email@example.com. If you do not have an account on Cisco.com, go to http://www.cisco.com/register and follow the directions to establish an account.
Feature Navigator is updated when major Cisco IOS software releases and technology releases occur. It contains feature information about mainline-, T-, S-, and P-trains. You can access Feature Navigator at the following URL:
Cisco IOS Software Documentation Set Contents
The Cisco IOS software documentation set consists of the Cisco IOS configuration guides, Cisco IOS command references, and several other supporting documents. The Cisco IOS software documentation set is 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 one or more configuration guides and one or more corresponding command references. 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. Use each configuration guide with its corresponding command reference.
On Cisco.com and the Documentation CD-ROM, two master hot-linked documents provide information for the Cisco IOS software documentation set.
On Cisco.com, beginning under the Service & Support heading:
Technical Documents: Documentation Home Page: Cisco IOS Software Configuration: Cisco IOS Release 12.2: Configuration Guides and Command References
On the Documentation CD-ROM:
Cisco IOS Software Configuration: Cisco IOS Release 12.2: Configuration Guides and Command References
Cisco IOS Release 12.2 Documentation Set
Table 8 lists the contents of the Cisco IOS Release 12.2 software documentation set, which is available in both electronic and printed form.
Note You can find the most current Cisco IOS documentation on Cisco.com and the Documentation CD-ROM. These electronic documents may contain updates and modifications made after the hard-copy documents were printed.
Technical Documents: Documentation Home Page: Cisco IOS Software Configuration: Cisco IOS Release 12.2
On the Documentation CD-ROM at:
Cisco Product Documentation: Cisco IOS Software Configuration: Cisco IOS Release 12.2
The following sections provide sources for obtaining documentation from Cisco Systems.
World Wide Web
You can access the most current Cisco documentation on the World Wide Web at the following sites:
Cisco documentation and additional literature are available in a CD-ROM package, which ships with your product. The Documentation CD-ROM is updated monthly and may be more current than printed documentation. The CD-ROM package is available as a single unit or as an annual subscription.
Cisco documentation is available in the following ways:
•Registered Cisco Direct Customers can order Cisco Product documentation from the Networking Products MarketPlace:
•Registered Cisco.com users can order the Documentation CD-ROM through the online Subscription Store:
•Nonregistered Cisco.com users can order documentation through a local account representative by calling Cisco corporate headquarters (California, USA) at 408 526-7208 or, in North America, by calling 800 553-NETS(6387).
If you are reading Cisco product documentation on the World Wide Web, you can submit technical comments electronically. Click Feedback in the toolbar and select Documentation. After you complete the form, click Submit to send it to Cisco.
You can e-mail your comments to firstname.lastname@example.org.
To submit your comments by mail, use the response card behind the front cover of your document, or write to the following address:
Attn Document Resource Connection
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, CA 95134-9883
We appreciate your comments.
Obtaining Technical Assistance
Cisco provides Cisco.com as a starting point for all technical assistance. Customers and partners can obtain documentation, troubleshooting tips, and sample configurations from online tools. For Cisco.com registered users, additional troubleshooting tools are available from the TAC website.
Cisco.com is the foundation of a suite of interactive, networked services that provides immediate, open access to Cisco information and resources at anytime, from anywhere in the world. This highly integrated Internet application is a powerful, easy-to-use tool for doing business with Cisco.
Cisco.com provides a broad range of features and services to help customers and partners streamline business processes and improve productivity. Through Cisco.com, you can find information about Cisco and our networking solutions, services, and programs. In addition, you can resolve technical issues with online technical support, download and test software packages, and order Cisco learning materials and merchandise. Valuable online skill assessment, training, and certification programs are also available.
Customers and partners can self-register on Cisco.com to obtain additional personalized information and services. Registered users can order products, check on the status of an order, access technical support, and view benefits specific to their relationships with Cisco.
To access Cisco.com, go to the following website:
Technical Assistance Center
The Cisco TAC website is available to all customers who need technical assistance with a Cisco product or technology that is under warranty or covered by a maintenance contract.
Contacting TAC by Using the Cisco TAC Website
If you have a priority level 3 (P3) or priority level 4 (P4) problem, contact TAC by going to the TAC website:
P3 and P4 level problems are defined as follows:
•P3—Your network performance is degraded. Network functionality is noticeably impaired, but most business operations continue.
•P4—You need information or assistance on Cisco product capabilities, product installation, or basic product configuration.
In each of the above cases, use the Cisco TAC website to quickly find answers to your questions.
To register for Cisco.com, go to the following website:
If you cannot resolve your technical issue by using the TAC online resources, Cisco.com registered users can open a case online by using the TAC Case Open tool at the following website:
Contacting TAC by Telephone
If you have a priority level 1(P1) or priority level 2 (P2) problem, contact TAC by telephone and immediately open a case. To obtain a directory of toll-free numbers for your country, go to the following website:
P1 and P2 level problems are defined as follows:
•P1—Your production network is down, causing a critical impact to business operations if service is not restored quickly. No workaround is available.
•P2—Your production network is severely degraded, affecting significant aspects of your business operations. No workaround is available.