Table Of Contents
Bridging and Routing Features for the Cisco uBR924 Cable Access Router
Related Features and Technologies
Configuring a Host Name and Password
Verifying the Host Name and Password
Configuration, Verification, and Troubleshooting Tips
Configuring Ethernet and Cable Access Router Interfaces
Verifying IP Address Configuration
Configuration, Verification, and Troubleshooting Tips
Reestablishing DOCSIS-Compliant Bridging
Verifying DOCSIS-Compliant Bridging
Customizing the Cable Access Router Interface
Basic Internet Access Bridging Configuration
Basic Internet Access Routing Configuration
Multicast-Enabled Routing Configuration
VoIP Bridging Configuration Using H.323v2
VoIP Routing Configuration Using H.323v2
cable-modem downstream saved channel
cable-modem upstream preamble qpsk
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 small- and 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.
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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 and . For more detailed descriptions of these options, see the "Configuration Options" section.
Figure 1 Cisco uBR924 in a Bridging Configuration
Figure 2 Cisco uBR924 in a Routing Configuration with a Hub
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:
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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.
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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.
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.
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.
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Figure 3 Typical Cisco Broadband Data Cable System
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.
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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.
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Figure 4 Cisco uBR924 in a Bridging Configuration
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.
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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
You can configure the Cisco uBR924 cable access router to function as a router by using one of the following methods:
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Benefits
The Cisco uBR924 cable access router provides the following benefits for data-over-cable applications:
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Restrictions
When using the Cisco uBR924 cable access router, keep the following restrictions and limitations in mind:
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CautionBefore 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•
· Regulatory Compliance and Safety Info. for the Cisco uBR924 Cable Access Router•
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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:
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In order to use the Cisco uBR924 cable access router for VoIP-over-cable applications, the following additional conditions must be met:
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Supported MIBs and RFCs
The Cisco uBR924 cable access router supports the following:
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Products & Ordering: Cisco Products: Network Management: CiscoWorks•
Cisco Product Documentation: Network Management: CiscoWorks•
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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.
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.
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.
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.
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CautionBefore 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.
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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.
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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:
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-configUsing 1888 out of 126968 bytes!version XX.X..!hostname cisco!enable secret 5 $1$60L4$X2JYOwoDc0.kqa1loO/w8/•
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cisco# exitcisco con0 is now availablePress RETURN to get started.cisco> enablePassword: guessmecisco#Configuration, Verification, and Troubleshooting Tips
If you are having trouble:
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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:
Verifying IP Address Configuration
To verify that you have assigned the correct IP address, enter the show arp command:
uBR924# show arpProtocol Address Age (min) Hardware Addr Type InterfaceInternet 172.16.1.1 - 0009.0613.6030 ARPA cable-modem0Internet 4.0.0.28 - 00e0.1ed7.524d ARPA Ethernet0Configuration, Verification, and Troubleshooting Tips
If you are having trouble:
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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:
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-configBuilding configuration...Current configuration:!version 12.0no service padno service password-encryptionservice udp-small-serversservice tcp-small-servers!hostname uBR924!!clock timezone - 4ip subnet-zero!!!voice-port 0!voice-port 1!!interface Ethernet0ip address 10.1.0.33 255.255.0.0no ip directed-broadcastip rip send version 2ip rip receive version 2no keepalive!interface cable-modem0ip address 172.16.1.42 255.255.0.0no ip directed-broadcastip rip send version 2ip rip receive version 2no keepalivecable-modem downstream saved channel 699000000 39no cable-modem compliant bridge!router ripnetwork 4.0.0.0network 172.16.0.0!ip classlessno ip http server!line con 0transport input noneline vty 0 4!endConfiguring 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:
When the cable interface comes up, the IP address and downstream channel are configured automatically.
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Verifying Bridging
To verify that routing has been disabled on all interfaces and that bridging has been reenabled, enter the show startup-config command from privileged EXEC mode:
uBR924# show startup-configBuilding configuration...Current configuration:!version 12.0service configno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!clock timezone - 4ip subnet-zerono ip routing!!voice-port 0!!voice-port 1!!interface Ethernet0no ip addressno ip directed-broadcastno ip route-cachebridge-group 59bridge-group 59 spanning-disabled!interface cable-modem0no ip addressno ip directed-broadcastno ip route-cacheno keepalivecable-modem downstream saved channel 699000000 36bridge-group 59bridge-group 59 spanning-disabled!ip classless!line con 0line vty 0 4login!endReestablishing DOCSIS-Compliant Bridging
To erase the current non-default cable access router configuration and return the unit to its factory default DOCSIS-compliant bridging configuration, perform the following task from privileged EXEC mode:
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uBR924#erase startup config
Erase the current configuration (assuming the current running configuration has been saved to NVRAM).
After entering this command, perform a warm reset of the Cisco uBR924 cable access router by pressing and holding down the Reset button for less than 10 seconds. For information on the location and operation of the Reset button, refer to the "Physical Description" section in the chapter "Installing the Cisco uBR924 Cable Access Router" in the Cisco uBR924 Cable Access Router Installation and Configuration Guide.
Verifying DOCSIS-Compliant Bridging
To verify that the cable access router is configured for DOCSIS-compliant bridging, enter the show startup-config command from privileged EXEC mode. The configuration should look like this:
uBR924# show startup-configBuilding configuration...Current configuration:!version 12.0service configno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!clock timezone - 4ip subnet-zerono ip routing!!!voice-port 0!!voice-port 1!!interface Ethernet0no ip addressno ip directed-broadcastno ip route-cachebridge-group 59bridge-group 59 spanning-disabled!interface cable-modem0no ip addressno ip directed-broadcastno ip route-cacheno keepalivecable-modem downstream saved channel 699000000 36bridge-group 59bridge-group 59 spanning-disabled!ip classlessno ip http server!line con 0transport input noneline vty 0 4login!endCustomizing the Cable Access Router Interface
Different geographical regions and different cable plants use different frequency bands. The Cisco uBR924 cable access router uses a built-in default frequency scanning feature to address this issue. After the cable access router finds a successful downstream frequency channel, it saves the channel and power setting to NVRAM. The cable access router recalls this value the next time it needs to synchronize its frequency or register with the cable service provider's CMTS.
However, you can customize the cable access router's interface configuration if you need to deviate from the default setting that ships with the unit. For example, you might need to specify a different compliant mode, modify the saved downstream channel setting and upstream power value, or enable a faster downstream search algorithm.
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To customize the cable access router interface, perform the following tasks, starting in global configuration mode:
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uBR924(config)#interface cable-modem 0Specify cable access router interface 0.
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uBR924(config-if)#cable-modem compliant bridgeEnable DOCSIS-compliant bridging.
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Modify the saved downstream channel setting and upstream power value. If you do this, you must specify an exact downstream frequency and a power value.1
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uBR924(config-if)#cable-modem fast-searchEnable a faster downstream search algorithm.
1 Use the no cable-modem downstream saved channel ds-frequency us-power command to remove a saved frequency and power setting from NVRAM.
Configuration Examples
This section provides the following configuration examples:
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Basic Internet Access Bridging Configuration
The following Cisco uBR924 cable access router configuration supports a typical residential Internet-access, data only subscriber:
Current configuration:!version 12.0service configno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!clock timezone - 4ip subnet-zerono ip routing!!voice-port 0!!voice-port 1!!interface Ethernet0ip address 172.16.1.40 255.255.0.0no ip directed-broadcastno ip route-cachebridge-group 59bridge-group 59 spanning-disabled!interface cable-modem0ip address 172.16.1.40 255.255.0.0no ip directed-broadcastno ip route-cachecable-modem downstream saved channel 699000000 36bridge-group 59bridge-group 59 spanning-disabled!ip classlessno ip http server!line con 0transport input noneline vty 0 4login!endBasic Internet Access Routing Configuration
The Cisco uBR924 cable access router can be configured to act as a router to preserve IP address space and limit broadcasts that can impact the performance of the network. A sample configuration file follows.
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Current configuration:!version 12.0service configno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!!clock timezone - 4ip subnet-zero!!!voice-port 0!voice-port 1!!interface Ethernet0ip address 10.1.0.33 255.255.0.0no ip directed-broadcast!interface cable-modem0ip address 172.16.1.42 255.255.0.0no ip directed-broadcastcable-modem downstream saved channel 699000000 39no cable-modem compliant bridge!router ripnetwork 4.0.0.0network 172.16.0.0!ip classlessno ip http server!line con 0transport input noneline vty 0 4!endMulticast-Enabled Routing Configuration
The following configuration is for a Cisco uBR924 that uses PIM sparse-dense mode and belongs to a specific multicast group. Other multicast routing protocols such as PIM sparse-mode or PIM dense-mode can be used.
Current configuration:!! Last configuration change at 23:16:44 - Thu Mar 18 1999!version 12.0service configno service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!!clock timezone - 4ip subnet-zero!!ip multicast-routingip dvmrp route-limit 20000!!voice-port 0!voice-port 1!!interface Ethernet0ip address 24.1.0.1 255.255.0.0no ip directed-broadcastip pim sparse-dense-modeno ip route-cacheno ip mroute-cache!interface cable-modem0ip address 10.1.0.25 255.255.0.0no ip directed-broadcastip pim sparse-dense-modeno ip route-cacheno ip mroute-cachecable-modem downstream saved channel 477000000 56no cable-modem compliant bridge!!router ripversion 2network 24.0.0.0network 10.0.0.0!!ip classlessno ip http server!!line con 0transport input noneline vty 0 4!endVoIP Bridging Configuration Using H.323v2
In this example, the Cisco uBR924 is configured for bridging, with an H.323v2 dial peer to another Cisco uBR924 attached to the same downstream interface on the headend CMTS.
Current configuration:!! Last configuration change at 21:54:41 - Thu Apr 29 1999! NVRAM config last updated at 21:56:20 - Thu Apr 29 1999!version 12.0no service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname 2007!!clock timezone - 3ip subnet-zerono ip routing!!voice-port 0input gain -3!voice-port 1input gain -3!dial-peer voice 1 potsdestination-pattern 6501port 0!dial-peer voice 2 potsdestination-pattern 6502port 1!dial-peer voice 62 voipdestination-pattern 620.session target ipv4:10.1.71.62!!interface Ethernet0ip address 10.1.71.65 255.255.255.0no ip directed-broadcastno ip route-cachebridge-group 59bridge-group 59 spanning-disabled!interface cable-modem0description DHCP Reserved Address 10.1.71.65ip address 10.1.71.65 255.255.255.0no ip directed-broadcastno ip route-cachecable-modem downstream saved channel 537000000 27bridge-group 59bridge-group 59 spanning-disabled!ip classlessno ip http server!!line con 0exec-timeout 0 0transport input noneline vty 0 4login!!endVoIP Routing Configuration Using H.323v2
In this example, the Cisco uBR924 is configured for IP routing, with an H.323v2 dial peer to another Cisco uBR924 attached to the same downstream interface on the headend CMTS.
Current configuration:!! No configuration change since last restart!version 12.0no service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname 2007!!class-map class-defaultmatch any!!clock timezone - 3ip subnet-zero!!voice-port 0!voice-port 1!dial-peer voice 1 potsdestination-pattern 6101port 0!dial-peer voice 2 potsdestination-pattern 6102port 1!dial-peer voice 101 voipdestination-pattern 620*codec g711alawsession target ipv4:10.1.71.62!!interface Ethernet0ip address 24.1.61.1 255.255.255.0no ip directed-broadcastno ip mroute-cache!interface cable-modem0ip address 10.1.71.61 255.255.255.0no ip directed-broadcastno ip mroute-cachecable-modem downstream saved channel 537000000 27no cable-modem compliant bridge!router ripversion 2network 10.0.0.0network 24.0.0.0no auto-summary <<==== Not necessary!no ip classlessip route 0.0.0.0 0.0.0.0 10.1.71.1no ip http server!!line con 0exec-timeout 0 0transport input noneline vty 0 4login!!endNAT/PAT Configuration
Current configuration:!! No configuration change since last restart!version 12.0no service padservice timestamps debug uptimeservice timestamps log uptimeno service password-encryption!hostname uBR924!!ip nat inside source list 1 interface cable-modem0 overloadclock timezone - -4!!interface Ethernet0ip address 10.1.1.1 255.255.255.0ip nat inside!interface cable-modem0ip address 24.3.90.20 255.255.255.0ip nat outsideno keepalivecable-modem downstream saved channel 627000000 54no cable-modem compliant bridge!ip default-gateway 24.3.90.2ip classlessip route 0.0.0.0 0.0.0.0 24.3.90.2access-list 1 permit any!line con 0line vty 0 4login!endCommand Reference
This section describes the following cable-modem interface commands for the Cisco uBR924 cable access router for Cisco IOS Release 12.0(5)T:
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All commands relating to VoIP applications are documented in the Cisco IOS Release 12.0 command references, or in Voice over IP for the Cisco AS5300, which can be accessed online or on the Documentation CDROM by going to New Features in Cisco IOS Release 12.0(3)T.
All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
cable-modem compliant bridge
To enable DOCSIS-compliant transparent bridging for a cable access router interface at startup, use the cable-modem compliant command from interface configuration mode. Use the no form of this command to disable DOCSIS-compliant bridging for the interface.
cable-modem compliant bridge
no cable-modem compliant bridge
Syntax Description
This command has no arguments or keywords.
Defaults
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Interface configuration
Command History
Usage Guidelines
It is normally not necessary to enter this command in data-over-cable bridging applications because DOCSIS-compliant bridging is enabled by default. If you wish to do full transparent bridging rather than DOCSIS-compliant bridging, use the no form of the command, then configure full transparent bridging using CLI commands. See the "Configuring Bridging" section for instructions.
Examples
The following example shows how to enter the cable-modem compliant bridge command for a cable access router interface, starting from global configuration mode:
uBR924(config)# interface cable-modem 0uBR924(config-if)# cable-modem compliant bridgeuBR924(config-if)#Related Commands
cable-modem downstream saved channel
To modify the saved downstream channel setting and upstream power value on a cable access router interface, enter the cable-modem downstream saved channel command from interface configuration mode. Use the no form of this command to remove the saved settings, which will be resaved at the next initialization cycle.
cable-modem downstream saved channel ds-frequency us-power
no cable-modem downstream saved channel ds-frequency us-power
Syntax Description
ds-frequency
Downstream channel frequency in Hz, which can be from 91000000 to 860000000.
us-power
Upstream power level in decibels per millivolt (dBmV), which can be from 8 to 61.
Defaults
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Command History
Usage Guidelines
This command is auto-generated by the operation of the cable MAC layer process. The DOCSIS RFI specification requires that cable modems remember the downstream frequency and upstream power of the last successfully ranged session. These parameters are called up as the first downstream frequency and upstream power to use the next time the cable modem is booted. This operation dramatically speeds up the channel search.
Use the no cable-modem downstream saved channel ds-frequency us-power command to remove the saved frequency and power setting from the running configuration, which will be resaved at the next initialization cycle.
Cisco recommends that this command NOT be used by end users of the Cisco uBR924 cable access router.
Examples
The following example shows how to remove the downstream frequency of 91000000 Hz and the upstream power level of 33 dBmV from the running configuration of a cable-modem interface, starting from global configuration mode.
uBR924(config)# interface cable-modem 0uBR924(config-if)# no cable-modem downstream saved channel 91000000 33uBR924(config-if)#Related Commands
cable-modem fast-search
To enable a faster downstream search algorithm on a cable access router interface, use the cable-modem fast-search command from interface configuration mode. Use the no form of this command to disable the downstream fast-search feature.
cable-modem fast-search
no cable-modem fast-search
Syntax Description
There are no keywords or arguments for this command.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
This feature speeds up the frequency search performed by the cable access router. Normally it takes the cable access router about 30 to 50 seconds to sample 30 to 50 frequencies. The cable-modem fast-search command can reduce this search time. However, there might be some cases where this fast-search algorithm might not perform as well as the default algorithm. Trial and error is the only way to discover how well this feature works for your environment.
Examples
The following example shows how to enter the cable-modem fast-search command, starting from global configuration mode:
uBR924(config)# interface cable-modem 0uBR924(config-if)# cable-modem fast-searchuBR924(config-if)#Related Commands
cable-modem upstream preamble qpsk
To enable the QPSK modulation scheme in the upstream direction from the cable access router interface to the headend, enter the cable-modem upstream preamble qpsk command from interface configuration mode. Use the no form of this command to disable upstream modulation for the interface.
cable-modem upstream preamble qpsk
no cable-modem upstream preamble qpsk
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Interface configuration
Command History
Usage Guidelines
Examples
The following example shows how to enter the cable-modem upstream preamble qpsk command for a cable access router interface, starting from global configuration mode:
uBR924(config)# interface cable-modem 0uBR924(config-if)# cable-modem upstream preamble qpskuBR924(config-if)#Related Commands
cable-modem voip best-effort
To allow voice calls to be sent upstream over the cable interface via best effort, use the cable-modem voip best-effort command from interface configuration mode. To disable best-effort voice calls, use the no form of this command.
cable-modem voip best-effort
no cable-modem voip best-effort
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled.
Command Modes
Interface configuration
Command History
Usage Guidelines
This command allows you to configure the voice traffic on a Cisco uBR924 to allow only calls having a high priority service identifier (SID) to be connected.
If the dynamic configuration of high priority queues for voice traffic fails, or if the far end cannot support the multiple SIDs and multiple classes of service required by high priority traffic, the flag set by this command will be checked. If enabled (the default setting), the call will be allowed to go through. If disabled, the call will fail.
Examples
The following example shows how to disable best-effort voice calls on a Cisco uBR924 cable interface, starting from global configuration mode:
uBR924(config)# interface cable-modem 0uBR924(config-if)# no cable-modem voip best-effortuBR924(config-if)#Related Commands
interface cable-modem
To specify the cable interface on a Cisco uBR924 cable access router, enter the interface cable-modem command from global configuration mode.
interface cable-modem number
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
When this command is entered, the Cisco uBR924 cable access router switches from global configuration mode to interface configuration mode.
Examples
The following example brings up cable access router interface 0 and displays the available cable-modem interface configuration commands:
uBR924(config)# interface cable-modem 0uBR924(config-if)# cable-modem ?compliant Enter compliant modes for interfacedownstream Downstream channel characteristicsfast-search Enable/disable the DS fast searchupstream upstream channel characteristicsvoip Options for Voice over IP traffic over the cable interfaceuBR924(config-if)#Related Commands
show bridge cable-modem
To display bridging information for a Cisco uBR924 cable access router, enter the show bridge cable-modem command from privileged EXEC mode.
show bridge cable-modem number
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Examples
Following is a sample output for this command:
uBR924# show bridge cable-modem 0Total of 300 station blocks, 298 freeCodes: P - permanent, S - selfBridge Group 59:describes the significant fields shown in the display.
Related Commands
Displays the current DHCP settings on point-to-point interfaces.
Displays information about the cable interface on the Cisco uBR924 cable access router.
show dhcp
To display the current DHCP settings on point-to-point interfaces, enter the show dhcp command from privileged EXEC mode.
show dhcp {lease | server}
Syntax Description
Defaults
No default behavior or values.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
You can use this command on any point-to-point type of interface that uses DHCP for temporary IP address allocation.
Examples
Following is sample output for the show dhcp lease command:
uBR924# show dhcp leaseTemp IP addr: 188.188.1.40 for peer on Interface: cable-modem0Temp sub net mask: 0.0.0.0DHCP Lease server: 4.0.0.32, state: 3 BoundDHCP transaction id: 2431Lease: 3600 secs, Renewal: 1800 secs, Rebind: 3150 secsTemp default-gateway addr: 188.188.1.1Next timer fires after: 00:58:01Retry count: 0 Client-ID: 0010.7b43.aa01describes the significant fields shown in the display.
Following is sample output for the show dhcp server command:
uBR924# show dhcp serverDHCP server: ANY (255.255.255.255)Leases: 1Offers: 1 Requests: 2 Acks: 1 Naks: 0Declines: 0 Releases: 0 Bad: 0TFTP Server Name: SOHOSERVERTIME0: 1.2.0.250, TIME1: 0.0.0.0Subnet: 255.255.255.0describes the significant fields shown in the display.
Related Commands
show interfaces cable-modem
To display information about the Cisco uBR924 cable access router's cable interface, enter the show interfaces cable-modem command from either user EXEC mode or privileged EXEC mode.
show interfaces cable-modem number [accounting | counters | crb | irb | type]
Syntax Description
Defaults
No default behavior or values.
Command Modes
User EXEC or privileged EXEC
Command History
Usage Guidelines
When this command is entered without a keyword, general information about the cable interface is displayed.
Examples
Traffic passing through the cable access router interface is shown in the following example:
uBR924# show interfaces cable-modem 0cable-modem0 is up, line protocol is upHardware is BCM3300, address is 0050.7366.2439 (bia 0050.7366.2439)Internet address is 5.2.0.11/16MTU 1500 bytes, BW 27000 Kbit, DLY 1000 usec,reliability 255/255, txload 1/255, rxload 1/255Encapsulation DOCSIS, loopback not setKeepalive set (10 sec)ARP type:ARPA, ARP Timeout 04:00:00Last input 00:00:00, output 00:00:00, output hang neverLast clearing of "show interface" counters 00:08:40Queueing strategy:fifoOutput queue 40/40, 52787 drops; input queue 0/75, 0 drops5 minute input rate 2000 bits/sec, 2 packets/sec5 minute output rate 94000 bits/sec, 154 packets/sec1074 packets input, 418472 bytes, 0 no bufferReceived 19 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort78771 packets output, 6326786 bytes, 0 underruns0 output errors, 0 collisions, 0 interface resets0 output buffer failures, 0 output buffers swapped outdescribes the significant fields shown in the display.
To display the number of packets and bytes of each protocol type passing through the cable access router interface, use the accounting option with the show interface cable-modem command:
uBR924# show interface cable-modem 0 accountingcable-modem0Protocol Pkts In Chars In Pkts Out Chars OutIP 545 185502 159 90240Trans. Bridge 3878 964995 12597 1611142ARP 73 3066 86 4128describes the fields shown in this display.
MIB counters on the cable interface are displayed in the next example:
uBR924# show int cable-modem 0 countersCable specific counters:Ranging requests sent : 50982Downstream FIFO full : 0Re-requests : 7277DS MAC Message Overruns: 0DS Data Overruns : 0Received MAPs : 254339485Received Syncs : 53059555Message CRC failures : 0Header CRC failures : 1394Data PDUs : 5853DS MAC messages : 307861745Valid Headers : 307869065Sync losses : 0Pulse losses : 1BW request failures : 6describes the counters shown in this display.
Information about routing and bridging protocols and filtering on the cable access router interface is displayed in the following example:
uBR924# show int cable-modem 0 crbcable-modem0Bridged protocols on cable-modem0:ipSoftware MAC address filter on cable-modem0Hash Len Address Matches Act Type0x00: 0 ffff.ffff.ffff 3877 RCV Physical broadcast0x2A: 0 0900.2b01.0001 0 RCV DEC spanning tree0x7A: 0 0010.7b43.aa01 573 RCV Interface MAC address0xC2: 0 0180.c200.0000 0 RCV IEEE spanning tree0xC2: 1 0180.c200.0000 0 RCV IBM spanning treedescribes the software MAC address filter information for the cable access router interface.
Related Commands
Debug Commands
All cable-modem debug commands used with the uBR924 cable access router are documented in Troubleshooting Tips for the Cisco uBR924 Cable Access Router, which can be accessed online or on the Documentation CDROM by going to New Features in Cisco IOS Release 12.0(5)T.
Note
All commands relating to VoIP applications are documented in the Debug Command Reference for Cisco IOS Release 12.0, which can be accessed online or on the Documentation CDROM by going to Cisco IOS Release 12.0 and selecting Supporting Documents.
