Cisco UBR924 User Manual

Bridging and Routing Features for the Cisco uBR924 Cable Access Router

Feature Overview

The Cisco uBR924 cable access router is a fully-functional Cisco IOS router and standards-based bidirectional cable modem that gives a residential or small office/home office (SOHO) subscriber high-speed Internet or Intranet access and packet telephone services via a shared two-way cable system and IP backbone network. The Cisco uBR924 is based on the current Data-Over-Cable Service Interface Specifications (DOCSIS) standards.

The Cisco uBR924 cable access router connects computers, telephone equipment, and other customer premises devices at a subscriber site to the service provider’s Hybrid/Fiber Coax (HFC) and IP backbone network. Subscribers can access the Internet at speeds of up to 10 Mbps as well as make telephone calls—all using the same cable system that delivers broadcast TV signals.

The Cisco uBR924 is a compact device that supports the direct connection of up to four PCs and has the familiar features and programming interface of other routers in Cisco’s extensive line of smalland medium-sized business product offerings. The Cisco uBR924 provides packet data transport and network address translation for TCP/IP applications between home or office computers and the cable headend.

Note This document describes the features available in Cisco IOS Release 12.0(5)T.

You can configure the cable access router to act as a bridge or as a router. See Figure 1 and Figure 2. For more detailed descriptions of these options, see the “Configuration Options” section on page 3.

Figure 1 Cisco uBR924 in a Bridging Configuration

Cisco uBR7200 series

CMTS

HFC network

Ethernet

CATV

coaxial cable

Cisco uBR900 series

cable access router

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 1

Ethernet

Feature Overview

Figure 2 Cisco uBR924 in a Routing Configuration with a Hub

CATV

Cisco uBR7246

CMTS

HFC network

coaxial cable

Cable

Modem

Ethernet Ethernet

HUB

LAN

13306

The Cisco uBR924 cable access router is referred to as a subscriber unit. The subscriber unit functions as an interface between the subscriber’s customer premises equipment (CPE) devices at the small office/home office and the cable operator’s network (the headend).

The Cisco uBR924 cable access router provides the following ports and connectors:

• A single F-connector interface to the cable network.

• Four RJ-45 (10BaseT Ethernet) hub ports to connect up to four computers directly to the cable

access router when configured for either routing mode or DOCSIS-compliant bridging mode.

Note When in routing mode, one of the four Ethernet ports can be connected to an Ethernet hub,

which then can connect additional computers or devices at the site.

• Two RJ-11 ports to connect two or more telephones to the cable system and IP backbone to

support Voice over IP (VoIP) digitized voice transmission via H.323v2.

• One RJ-11 port to connect to a standard, analog telephone line (optional) to provide a backup

Plain Old Telephone Service (POTS) connection to the Public Switched Telephone Network (PSTN) should the cable access router lose power.

• One RJ-45 console port to connect to an ASCII terminal or PC when locally troubleshooting or

reconfiguring the cable access router.

When supporting basic Internet access, the cable interface requires no configuration or setup procedures other than to connect the Cisco uBR924 to the cable system. The unit is configured automatically using a configuration file generated by the cable service provider and delivered via the Cisco universal broadband router installed at the cable headend. The headend router provides a path from the cable access router to the Dynamic Host Configuration Protocol (DHCP) server for PC address assignment.

Note To support VoIP applications, a Cisco IOS image that supports voice must be downloaded to

the Cisco uBR924 in addition to the configuration file that is automatically downloaded at power-up. For information on downloading IOS images to the Cisco uBR924, see the Cisco uBR924 Cable Access Router Installation and Configuration Guide.

Cisco IOS Release 12.0(5)T

The PCs connected to the Cisco uBR924 cable access router must be configured for Internet Protocol (IP). Using DHCP, the universal broadband router assigns an IP subnet address to the cable access router each time it connects to the network. The IP addresses of the cable access router and the individual PCs attached to it enable the universal broadband router to route data to and from the PCs.

Configuration Options

After the Cisco uBR924 is installed and the connected PCs are configured for IP, and after DHCP services are enabled and communication to the headend is established, the Cisco universal broadband router downloads configuration information to the cable access router. The initial configuration connection to the headend can take several minutes.

Figure 3 illustrates a broadband data cable system. Data transmitted to a Cisco uBR924 cable access router from the CMTS shares a 27 Mbps or 26 Mbps, 6 MHz data channel in the 88 to 860 MHz range. The Cisco uBR924 cable access router shares an upstream data rate of up to 10 Mbps on a 200 kHz-wide to 3.2 MHz-wide channel in the 5 to 42 MHz range.

Note End-to-end throughput varies based on the design and loading of network components, the

mix of traffic, the processing speed and interface of the host server(s), the processing speed and local Ethernet performance of the subscriber’s computer, as well as other parameters.

Figure 3 Typical Cisco Broadband Data Cable System

WAN

Switch/router

Servers

Internal backbone

and

worldwide internet

Configuration Options

The Cisco uBR924 cable access router is usually configured automatically at startup via a configuration file generated by the cable service provider and downloaded to the cable access router; however, you can also manually configure the cable access router to function either as a bridge or as a router. The following sections give brief descriptions of both applications.

CMTS

rack equipment

Cable System Headend

Upstream and downstream data interfaces Operation support system interface Downstream RF interface Upstream RF interface

Combiner

Cisco uBR900 series

cable access router

HFC cable plant

Fiber

18197

Residence or SOHO subscriber site: subscriber RF interface Ethernet interface

Note When the Cisco uBR924 cable access router is shipped from the factory, it is configured by

default for DOCSIS-compliant bridging.

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 3

Feature Overview

Bridging

The Cisco uBR924 cable access router complies with the DOCSIS standards for interoperable cable access routers; it supports full transparent bridging as well as DOCSIS-compliant transparent bridging.

In bridging applications, the Cisco uBR924 acts as a transparent bridge for up to four PCs plugged directly into the four Ethernet ports on the rear panel of the unit. The cable access router is connected to the Internet via the coaxial cable. All four Ethernet ports are treated as one Ethernet interface by the Cisco IOS software. The IP addresses for the PCs and the coaxial cable interface are typically in the same subnet, although this is not a requirement.

Note If the attached PCs and the coaxial cable interface are in different IP subnets, the cable

interface must have a secondary address.

Figure 4 Cisco uBR924 in a Bridging Configuration

Cisco uBR7200 series

CMTS

HFC network

CATV

coaxial cable

Cisco uBR900 series

cable access router

Ethernet

DOCSIS-compliant transparent bridging is the default configuration of the Cisco uBR924 cable access router. If your cable service provider is using a DHCP server, all you need to do is connect the cables and power on the cable access router; your service provider’s configuration program will automatically configure both the coaxial cable interface and the bridging functionality. You do not need to set up IP addresses for the attached PCs or enter any Command Line Interface (CLI) configuration commands. This type of operation is called plug-and-play bridging.

In DOCSIS-compliant bridging mode, the cable access router is able to locate a downstream and upstream channel; find TOD, TFTP, and DHCP server(s); obtain an IP address; download a DOCSIS configuration file; and obtain DHCP parameters to work in a bridging mode. For a better understanding of the processes involved, refer to the online Cisco uBR924 Cable Access Router Installation and Configuration Guide.

In addition to the plug-and-play method of operation, you can configure a bridging application on the Cisco uBR924 using the CLI. See the sections “Configuring Bridging” on page 16 and “Customizing the Cable Access Router Interface” on page 19 for details.

Cisco IOS Release 12.0(5)T

Note The ability of the cable access router to learn CPE MAC addresses in the DOCSIS-compliant

bridging mode is controlled by the MAC CPE option in the DOCSIS configuration file. The Cisco uBR924 cable access router defaults to learning only one CPE MAC address unless this option is set to 4. The maximum number of CPE MAC addresses that can be supported in bridging mode is

15.

Routing

The Cisco uBR924 cable access router can also be configured to act as a router to preserve IP address space and limit broadcasts that can impact the performance of the network. A typical use would be if you are connecting the cable access router to an internal Ethernet hub that is connected to an existing PC network. You can also connect the cable access router directly to as many as four PCs via the Ethernet ports on the rear panel.

The cable access router is automatically configured to use the IP address of the Cisco headend cable router as the cable access router’s default IP gateway.

Figure 5 Cisco uBR924 in a Routing Configuration with a Hub

CATV

Cisco uBR7246

CMTS

HFC network

coaxial cable

Cable

Modem

Ethernet Ethernet

HUB

LAN

13306

Routing

Benefits

You can configure the Cisco uBR924 cable access router to function as a router by using one of the following methods:

• By using TFTP to download a configuration file from the headend router to the cable access

router that automatically configures it for routing.

• By connecting an ASCII terminal or PC to the console port on the back of the cable access router

and using the CLI. See the sections “Configuring a Host Name and Password” on page 12 and “Customizing the Cable Access Router Interface” on page 19 for details

The Cisco uBR924 cable access router provides the following benefits for data-over-cable applications:

• Allows telecommuters and small office/home office customers to leverage the high-bandwidth,

low-cost, IP-based data and voice services offered by cable operators

• Enables the cost-effective deployment of advanced routing capabilities to the small office or

home office site

• Prioritizes voice traffic ahead of data traffic, ensuring quality of service (QoS) over a shared cable

infrastructure

• Leverages Cisco’s industry-standard routing hardware and Cisco IOS software to deliver

advanced networking services and applications such as virtual private networks (VPNs), support for multi-protocol networks, firewall security, and the ability to cost-effectively deploy local area networks (LANs)

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 5

Restrictions

When using the Cisco uBR924 cable access router, keep the following restrictions and limitations in mind:

• The Cisco uBR924 cable access router is able to implement multiples classes of service (CoS)

on the cable interface; however, separate CoS streams are only available when the cable access router is connected to a headend that supports multiple classes of service per cable access router. In addition, the configuration file downloaded to the cable access router must specify the use of multiple classes of service.

• If the Cisco uBR924 cable access router is connected to a DOCSIS 1.0 headend that does not

support multiple CoS per cable access router, voice and data will be mixed, and voice traffic will be transmitted on a best effort basis. This may cause poorer voice quality and lower data throughput when calls are being made from the cable access router’s telephone ports. Voice quality is also affected when transmitting or downloading large files, as well as by other significant network traffic.

Note The Cisco uBR924 cable access router is typically configured at the headend. Most subscriber

sites do not permit local configuration. Remote configuration is either disabled or routinely reset to settings in the provisioning or billing systems.

Caution Before attempting to reconfigure a Cisco uBR924 cable access router at a subscriber site, contact

your network management, provisioning manager, or billing system administrator to ensure remote configuration is allowed. If remote configuration is disabled, settings you make and save at the local site will not remain in effect after the cable access router is powered off and back on. Instead, settings will return to the previous configuration.

Related Features and Technologies

The Cisco uBR924 cable access router is intended to be used in conjunction with a Cisco uBR7246 or a Cisco uBR7223 universal broadband router located at the cable operator’s headend facility. Other compatible headend devices may also be used with the Cisco uBR924.

Related Documents

For related information on the Cisco uBR924 cable access router, refer to the following documents:

• Cisco uBR924 Cable Access Router Quick Start Guide

• Cisco uBR924 Cable Access Router Installation and Configuration Guide

• Regulatory Compliance and Safety Info. for the Cisco uBR924 Cable Access Router

• Cisco uBR7246 Installation and Configuration Guide

• Cisco uBR7223 Installation and Configuration Guide

Cisco IOS Release 12.0(5)T

• Cisco uBR7200 Series Configuration Notes

• Cisco Network Registrar for the uBR7200 Series

• Regulatory and Safety Compliance for the Cisco uBR7246

• Regulatory and Safety Compliance for the Cisco uBR7223

• Cisco uBR7200 Series Universal Broadband Router Features

Supported Platforms

The Cisco uBR924 cable access router is a standalone device; it works in conjunction with the Cisco uBR7246 and the Cisco uBR7223 universal broadband routers.

Prerequisites

In order to use the Cisco uBR924 cable access router for data-over-cable applications, the following tasks must be completed:

• All required CMTS routers, servers (DHCP, TFTP and TOD), network management systems,

and/or other configuration or billing systems to be used in your network must be installed, configured, and operational. If you are using a Cisco uBR7246 or uBR7223 universal broadband router at the cable headend, refer to the Cisco uBR7246 Installation and Configuration Guide or the Cisco uBR7223 Installation and Configuration Guide for detailed information.

• Based on the quality and capacity of your cable plant, your system administrator or network

planner must define your network’s IP address allocation plan; spectrum management plan outlining the recommended operating parameters to optimize performance; channel plan identifying the channels available to assign to specific Cisco uBR924 cable access routers; and dial plan based on the supported VoIP protocol.

Supported Platforms

• The CMTS system administrator or appropriate personnel must specify the policy parameters for

the Cisco uBR924 and all computers and other customer premises devices to be supported at subscriber sites. Refer to Cisco’s Network Registrar (CNR) product documentation.

• The CMTS system administrator or appropriate personnel must define and push DHCP and

Cisco uBR924 configuration files to the appropriate servers such that each router, when initialized, can transmit a DHCP request, receive its IP address, obtain its TFTP and TOD server addresses, and download its configuration file or updated Cisco IOS image.

Note The MAC address ensures that each router downloads only the file(s) intended for it.

• The Cisco uBR924 cable access router must be physically installed and cabled as follows:

— To the headend via CATV coaxial cable. (High-quality, shielded RF coaxial cable with at

least 80% braid is recommended.)

— To at least one PC via the straight-through yellow Ethernet cable supplied with the cable

access router. Refer to the Cisco uBR924 Cable Access Router Quick Start Guide for detailed information.

Note When the Cisco uBR924 is connected to an Ethernet hub, a crossover cable must be used.

Category 5 UTP (10BaseT Ethernet) cable with RJ-45 connectors is recommended.

Note For subscriber sites that support multiple telephones or fax devices on a telephone line, all

wiring associated with the telephone line extension must be in place. Inside wiring must be in compliance with the country of operation to prevent degradation of service.

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 7

Supported MIBs and RFCs

• The CMTS system administrator must ensure appropriate databases are updated to activate and

support the new subscriber account in the provisioning, billing and/or network management systems in place for your network once each router is registered with the CMTS.

• The PC(s) connected to the Cisco uBR924 cable access router must be configured for IP.

• Cisco IOS Release 11.3(4)NA or later must be running on the Cisco uBR924 cable access router.

When the cable access router is up and running, you can display the IOS release number by entering the show version command from user EXEC mode.

Note If the Cisco uBR7246 universal broadband router at the cable headend is using MC16 modem

cards, Cisco IOS Release 11.3(7)NA or later must be running on the Cisco uBR924 cable access router.

In order to use the Cisco uBR924 cable access router for VoIP-over-cable applications, the following additional conditions must be met:

• In order to run VoIP Fax, the uBR924 cable access router must be configured for voice and you

must be using Cisco IOS Release 12.0(5)T or higher.

Supported MIBs and RFCs

The Cisco uBR924 cable access router supports the following:

• Cisco Standard MIBs:

— Cisco Product MIB

— Cisco Chassis MIB

— Cisco Syslog MIB

— Cisco Flash MIB

— Bridge MIB

— IF MIB

— MIB-II

• Cisco VoIP MIBs:

— Cisco Voice IF MIB

— Cisco Voice Dial-Control MIB

— Cisco Voice Analog IF MIB

— Cisco Dial-Control MIB

• Radio Frequency Interface Specification—Developed by the Multimedia Cable Network System

(MCNS) consortium. It defines the radio-frequency interface specification for high-speed data-over-cable systems.

Cisco IOS Release 12.0(5)T

• CiscoWorks—Network management program for planning, troubleshooting, and monitoring

Cisco internetworks. CiscoWorks uses Simple Network Management Protocol (SNMP) to monitor all SNMP devices.

— For more information about CiscoWorks on CCO, follow this path:

Products & Ordering: Cisco Products: Network Management: CiscoWorks

— For more information about CiscoWorks on the Documentation CD-ROM, follow this path:

Cisco Product Documentation: Network Management: CiscoWorks

• Radio Frequency Interface (RFI) MIB—Specific to Data-Over-Cable Service Interface

Specification (DOCSIS) cable implementations. The RIF MIB provides an interface that permits management of the Cisco uBR924 cable access router over the cable or Ethernet interface. Using SNMP management applications, this MIB allows access to statistics such as MAC, driver configuration, and counters.

• Cable Device MIB—Records statistics related to the configuration and status of the

Cisco uBR924 cable access router. Statistics include an events log and device status. The Cable Device MIB is very similar to the RFI MIB in that both allow access to statistics; they are different in that the Cable Device MIB reports statistics on the cable access router, while the RFI MIB reports statistics on the radio frequency transmissions over the cable television line.

For descriptions of supported MIBs and how to use MIBs, see Cisco’s MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

List of Terms and Acronyms

broadband—Transmission system that combines multiple independent signals onto one cable. In the cable industry, broadband refers to the frequency-division multiplexing of many signals in a wide bandwidth of RF frequencies using a hybrid fiber-coaxial (HFC) network.

List of Terms and Acronyms

CATV—Originally stood for Community Antenna Television. Now refers to any coaxial or fiber cable-based system that provides television services.

cable modem (CM)—A modulator-demodulator device that is placed at subscriber locations to convey data communications on a cable television system. The Cisco uBR924 cable access router is also a cable modem.

Cable Modem Termination System (CMTS)—A termination system located at the cable television system headend or distribution hub which provides complementary functionality to the cable modems, enabling data connectivity to a wide-are network.

cable router—A modular chassis-based router optimized for data-over-CATV hybrid fiber-coaxial (HFC) applications.

carrier—A signal on which another, lower-frequency signal is modulated in order to transport the lower-frequency signal to another location.

Carrier-to-Noise—C/N (also CNR). The difference in amplitude between the desired RF carrier and the noise in a portion of the spectrum.

channel—A specific frequency allocation and bandwidth. Downstream channels used for television are 6 MHz wide in the United States; 8 MHz wide in Europe.

CM—cable modem.

CMTS—Cable Modem Termination System.

coaxial cable—The principal physical media over which CATV systems are built.

CPE—Customer Premises Equipment

dB—Decibel. A measure of the relative strength of two signals.

dBm—Decibels with respect to one milliwatt. A unit of RF signal strength used in satellite work and

other communications applications.

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 9

List of Terms and Acronyms

dBmV—Decibels with respect to one millivolt in a 75-ohm system. The unit of RF power used in CATV work in North America.

DHCP—Dynamic Host Configuration Protocol. This protocol provides a mechanism for allocating IP addresses dynamically so that addresses can be reused when hosts no longer need them.

DOCSIS—Data Over Cable Service Interface Specification. Defines technical specifications for equipment at both subscriber locations and cable operators’ headends.

downstream—The set of frequencies used to send data from a headend to a subscriber.

FDM—Frequency Division Multiplexing. A data transmission method in which a number of

transmitters share a transmission medium, each occupying a different frequency.

FEC—Forward Error Correction. In data transmission, a process by which additional data is added that is derived from the payload by an assigned algorithm. It allows the receiver to determine if certain classes of errors have occurred in transmission and, in some cases, allows other classes of errors to be corrected.

headend—Central distribution point for a CATV system. Video signals are received here from satellite (either co-located or remote), frequency converted to the appropriate channels, combined with locally originated signals, and rebroadcast onto the HFC plant. For a CATV data system, the headend is the typical place to create a link between the HFC system and any external data networks.

HFC—Hybrid fiber-coaxial (cable network). Older CATV systems were provisioned using only coaxial cable. Modern systems use fiber transport from the headend to an optical node located in the neighborhood to reduce system noise. Coaxial cable runs from the node to the subscriber. The fiber plant is generally a star configuration with all optical node fibers terminating at a headend. The coaxial cable part of the system is generally a trunk-and-branch configuration.

host—Any end-user computer system that connects to a network. In this document, the term host refers to the computer system connected to the LAN interface of the cable access router.

ingress noise—Over-the-air signals that are inadvertently coupled into the nominally closed coaxial cable distribution system. Ingress noise is difficult to track down and intermittent in nature.

MAC layer—Media Access Control sublayer. Controls access by the cable access router to the CMTS and to the upstream data slots.

MCNS—Multimedia Cable Network System Partners Ltd. A consortium of cable companies providing service to the majority of homes in the United States and Canada. This consortium has decided to drive a standard with the goal of having interoperable cable access routers.

MSO—Multiple System Operator. A cable service provider that operates in more than one geographic area, thus having multiple headend facilities.

narrowband—A single RF frequency.

NTSC—National Television Systems Committee. A United States TV technical standard, named

after the organization that created the standard in 1941. Specifies a 6 MHz-wide modulated signal.

PAL—Phase Alternating Line. The TV system used in most of Europe, in which the color carrier phase definition changes in alternate scan lines. Utilizes an 8 MHz-wide modulated signal.

QAM—Quadrature Amplitude Modulation. A method of modulating digital signals onto a radio-frequency carrier signal in which the value of a symbol consisting of multiple bits is represented by amplitude and phase states of the carrier. QAM is a modulation scheme mostly used in the downstream direction (64-QAM, 256-QAM). 16-QAM is expected to be usable in the upstream direction. Numbers indicate number of code points per symbol. The QAM rate or the number of points in the QAM constellation can be computed by 2 raised to the power of <number of bits/symbol>. For example, 16-QAM has 4 bits per symbol, 64-QAM has 6 bits per symbol, and 256-QAM has 8 bits per symbol.

Cisco IOS Release 12.0(5)T

Configuration Tasks

QPSK—Quadrature Phase-Shift Keying. A digital modulation method in which there are 2 data bits represented with each baud symbol.

ranging—The process of acquiring the correct timing offset such that the transmissions of a cable access router are aligned with the correct mini-slot boundary.

RF—Radio frequency. The portion of the electromagnetic frequency spectrum from 5 MHz to approximately 860 MHz.

SECAM—TV system used in France and elsewhere, utilizing an 8 MHz-wide modulated signal.

SID (Service ID)—A number that defines (at the MAC sublayer) a particular mapping between a

cable access router (CM) and the CMTS. The SID is used for the purpose of upstream bandwidth allocation and class-of-service management.

Signal-to-Noise—S/N (also SNR). The difference in amplitude between a baseband signal and the noise in a portion of the spectrum.

spectrum reuse—CATV’s most fundamental concept. Historically, the over-the-air spectrum has been assigned to many purposes other than that of carrying TV signals. This has resulted in an inadequate supply of spectrum to serve the needs of viewers. Cable can reuse spectrum that is sealed in its aluminum tubes.

subscriber unit (SU)—An alternate term for cable access router. See cable access router.

upstream—The set of frequencies used to send data from a subscriber to the headend.

Configuration Tasks

The Cisco uBR924 cable access router typically is configured automatically on power-up using a configuration file generated by the cable service provider and delivered via the Cisco uBR7246 or the Cisco uBR7223 universal broadband router installed at the cable headend. All of the configuration tasks listed below are optional.

• Configuring a Host Name and Password on page 12

• Configuring Ethernet and Cable Access Router Interfaces on page 13

• Configuring Routing on page 14

• Configuring Bridging on page 16

• Reestablishing DOCSIS-Compliant Bridging on page 18

• Customizing the Cable Access Router Interface on page 19

Caution Before attempting to reconfigure a Cisco uBR924 cable access router at a subscriber site, contact

Note Console sessions and TTY sessions are supported by the cable access router.

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 11

Configuring a Host Name and Password

One of the first configuration tasks you might want to perform is to configure a host name and set an encrypted password. Configuring a host name allows you to distinguish multiple Cisco uBR924 cable access routers from each other. Setting an encrypted password allows you to prevent unauthorized configuration changes.

Note Passwords are case sensitive.

To configure a host name and an encrypted password for a Cisco uBR924 cable access router, perform the following tasks, starting in global configuration mode:

Step Command Purpose

uBR924(config)# hostname cisco

cisco(config)#

cisco(config)# enable secret guessme

cisco(config)# line console 0

cisco(config-line)# exec-timeout 0 0

cisco(config-line)# exit cisco(config)#

Change the name of the uBR924 to a meaningful name. Substitute your host name for cisco.

Enter an enable secret password. This password provides access to enable (privileged EXEC) mode.

After configuring a password, when you enter enable at the EXEC prompt, you must enter the enable secret password to gain access to configuration mode. Substitute your enable secret password for guessme.

Enter line configuration mode to configure the console port.

Prevent the EXEC facility from timing out if you do not type any information on the console screen for an extended period.

Exit back to global configuration mode.

Verifying the Host Name and Password

To verify that you configured the correct host name and password, enter the show running-config command from global configuration mode:

cisco(config)# show running-config Using 1888 out of 126968 bytes ! version XX.X . . ! hostname cisco ! enable secret 5 $1$60L4$X2JYOwoDc0.kqa1loO/w8/

• Check the host name and encrypted password displayed near the top of the command output.

Cisco IOS Release 12.0(5)T

Configuration, Verification, and Troubleshooting Tips

• Exit global configuration mode and attempt to reenter it using the new enable password:

cisco# exit

cisco con0 is now available Press RETURN to get started. cisco> enable Password: guessme cisco#

Configuration, Verification, and Troubleshooting Tips

If you are having trouble:

• Make sure Caps Lock is off.

• Make sure you entered the correct passwords. Passwords are case sensitive.

Configuring Ethernet and Cable Access Router Interfaces

To assign an IP address to the Ethernet or cable access router interface so that it can be recognized as a device on the Ethernet LAN, perform the following tasks, starting in global configuration mode:

Step Command Purpose

uBR924(config)# interface ethernet 0

uBR924(config)# interface modem-cable0

uBR924(config-if)#

uBR924(config-if)# ip address 172.16.1.1 255.255.255.0

uBR924(config-if)# Ctrl-Z

uBR924#

%SYS-5-CONFIG_I: Configured from console by console

Enter interface configuration mode for the Ethernet and/or the cable access router interface.

Assign the appropriate IP address and subnet mask to the interface.

Return to privileged EXEC mode.

This message is normal and does not indicate an error.

Verifying IP Address Configuration

To verify that you have assigned the correct IP address, enter the show arp command:

uBR924# show arp Protocol Address Age (min) Hardware Addr Type Interface Internet 172.16.1.1 - 0009.0613.6030 ARPA cable-modem0 Internet 4.0.0.28 - 00e0.1ed7.524d ARPA Ethernet0

Configuration, Verification, and Troubleshooting Tips

If you are having trouble:

• Make sure you are using the correct IP address.

• Make sure the cable interface is not shut down. Use the show running-config command to check the cable

interface status.

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 13

Configuring Routing

DOCSIS-compliant transparent bridging is the factory default configuration of the Cisco uBR924 cable access router. To change the configuration of your cable access router from bridging to routing using the CLI, perform the following tasks, starting in global configuration mode:

Step Command Purpose

uBR924(config)#interface cable-modem0

uBR924(config-if)#no cable-modem compliant bridge

uBR924(config-if)#no bridge-group 59

uBR924(config-if)#end

uBR924(config)#ip routing

uBR924(config)#ip subnet-zero

uBR924(config)#ip route <IP address of CMTS> <subnet

mask of CMTS>

uBR924(config)#router rip

5 uBR924(config-router)#network network-number Specify the network connected to the cable access router

uBR924(config-router)#end

uBR924(config)#interface cable-modem0

uBR924(config-if)#ip rip receive v 2

uBR924(config-if)#ip rip send v 2

uBR924(config-if)#end

uBR924(config)#interface ethernet0

uBR924(config-if)#no bridge-group 59

uBR924(config-if)#ip rip receive v 2

uBR924(config-if)#ip rip send v 2

uBR924(config-if)#Ctrl-z

uBR924#copy running-config startup-config Building configuration...

Enter interface configuration mode for the cable access router interface.

Turn off DOCSIS-compliant bridging.

Remove the default bridge group assignment from the cable interface.

Return to global configuration mode.

Enable IP routing for the cable access router.

Enable the use of subnet zero for interface addresses and routing updates.

Create a static route to the CMTS to make sure that Time of Day (TOD) packets are properly routed out of the cable access router.

Enter router configuration mode and enable Routing Information Protocol (RIP) on the cable access router.

on which the RIP process will operate. If the cable access router is attached to more than one network, enter each IP address in a separate command.

Exit router configuration mode. Return to interface configuration mode for the cable access router interface.

Specify that only RIP Version 2 packets will be received on the coaxial cable interface.

Specify that only RIP Version 2 packets will be sent on the coaxial cable interface.

Exit interface configuration mode for the cable access router interface and enter interface configuration mode for the Ethernet0 interface.

Remove the default bridge group assignment from the Ethernet0 interface.

Specify that only RIP Version 2 packets will be received on this Ethernet interface.

Specify that only RIP Version 2 packets will be sent on this Ethernet interface.

Return to privileged EXEC mode. Save the configuration to nonvolatile RAM so that it won’t be lost in the event of a reset, power cycle, or power outage.

Cisco IOS Release 12.0(5)T

Verifying Routing

To verify that bridging is not configured, routing is enabled, and that Routing Information Protocol is configured on the interfaces, enter the show startup-config command:

uBR924# show startup-config Building configuration...

Current configuration: ! version 12.0 no service pad no service password-encryption service udp-small-servers service tcp-small-servers ! hostname uBR924 ! ! clock timezone - 4 ip subnet-zero ! ! ! voice-port 0 ! voice-port 1 ! ! interface Ethernet0 ip address 10.1.0.33 255.255.0.0 no ip directed-broadcast ip rip send version 2 ip rip receive version 2 no keepalive ! interface cable-modem0 ip address 172.16.1.42 255.255.0.0 no ip directed-broadcast ip rip send version 2 ip rip receive version 2 no keepalive cable-modem downstream saved channel 699000000 39 no cable-modem compliant bridge ! router rip network 4.0.0.0 network 172.16.0.0 ! ip classless no ip http server ! line con 0 transport input none line vty 0 4 ! end

Verifying Routing

Bridging and Routing Features for the Cisco uBR924 Cable Access Router 15

Configuring Bridging

The Cisco uBR924 cable access router is configured for DOCSIS-compliant transparent bridging by default. If it becomes necessary to reconfigure the unit for bridging after it has been configured for routing, you can erase the routing configuration and return the unit to factory default configuration settings, or you can reconfigure the unit manually using the CLI. To return the cable access router to factory default settings, see the section “Reestablishing DOCSIS-Compliant Bridging” on page 18 for details. To reconfigure the cable access router manually, perform the following tasks, starting in global configuration mode:

Step Command Purpose

uBR924(config)#no service pad

uBR924(config)#no service password-encryption

uBR924(config)#no ip routing

uBR924(config)#interface Ethernet0

uBR924(config-if)#no ip address

uBR924(config-if)#no ip route-cache

uBR924(config-if)#bridge-group bridge-group

8 uBR924(config-if)#bridge-group bridge-group

spanning-disabled

uBR924(config-if)#end

uBR924(config)#interface cable-modem0

uBR924(config-if)#no ip address

uBR924(config-if)#no ip route-cache

uBR924(config-if)#no keepalive

uBR924(config-if)#cable-modem compliant bridge

uBR924(config-if)#bridge-group bridge-group

spanning-disabled

uBR924(config-if)#end

uBR924(config)#ip classless

uBR924(config)#line console 0

Disable packet assembler/disassembler commands; prevent the uBR924 from accepting incoming or outgoing Packet Assembler/Disassembler (PAD) connections.

Disable password encryption.

Disable IP routing on the uBR924.

Enter interface configuration mode for the Ethernet0 interface.

Disable the IP address on the Ethernet0 interface.

Disable high-speed switching caches for IP routing.

Assign the Ethernet0 interface to a bridge group. The bridge group must be an integer between 1 and 63.

Disable spanning tree on the Ethernet interface.

Exit interface configuration mode for the Ethernet0 interface and enter interface configuration mode for the cable access router interface.

Disable the IP address of the coaxial cable interface, if one has been set. The uBR7246 cable router assigns an IP address to the cable access router each time it connects to the network.

Disable high-speed switching caches for IP routing on the cable interface.

Disable keepalives on the cable interface.

Enable DOCSIS-compliant bridging.

Assign the cable access router interface to a bridge group. The bridge group must be an integer from 1 to 63. (The default is 59.)

Disable spanning tree on the cable interface.

Exit interface configuration mode.

(Optional) At times, the uBR924 might receive packets destined for a subnet of a network that has no network default route. This global configuration mode command allows the Cisco IOS software to forward such packets to the best network route possible.

Enter line configuration mode to configure the console port.

Cisco IOS Release 12.0(5)T

+ 36 hidden pages