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CiscouBR924 Software Configuration Guide
OL-0337-05 (8/2002)
Chapter2 DOCSIS-Bridging Configuration
Configuring the Attached CPE Devices
Configuring the Attached CPE Devices
In its “plug-and-play” bridging mode, the Cisco uBR924 router does not need any additional
configuration to support the computers or other CPE devices that will access the Internet through the
router’s connection to the cable network. However, the PCs and CPE devices must be configured to
support DHCP allocation of IP addresses.
Each computer and CPE device performs this configuration differently. For Windows 95, for example,
you would open up the Network control panel, select the computer’s TCP/IP Ethernet adapter, and set
the IP address configuration to “Obtain and IP address automatic ally.”
Reconfiguring DOCSIS-Compliant Bridging
To reconfigure the Cisco uBR924 router to support DOCSIS-compliant bridging after it has been
configured for routing, log in to the Cisco uBR924 router, enter global c onfiguration mode, and enter the
following commands:
Command Purpose
Step1 uBR924(config)#no ip routing Disable IP routing on the Cisco uBR924 router.
Step2 uBR924(config)#int e 0 Enter interface configuration mode for the Ethernet
interface.
Step3 uBR924(config-if)# no ip address Remove the IP address from the Ethernet interface.
Step4 uBR924(config-if)# no ip route-cache Remove the high-speed switching caches for IP
routing.
Step5 uBR924(config-if)# bridge-group bridge-group Assign the Ethernet interface to a bridge spanning
group (choose an arbitrary integer from 1–63).
Step6 uBR924(config-if)# bridge-group bridge-group
spanning-disabled
Disable the spanning tree on the Ethernet interfac e.
Step7 uBR924(config-if)# exit Exit the interface configuration mode for the
Ethernet interface.
Step8 uBR924(config)# int c 0 Enter interface configuration mode for the cable
interface.
Step9 uBR924(config-if)# no ip address Remove the IP address from the cable interface.
Step10 uBR924(config-if)# no keep alive Disable keepalive messages on the cable interface.
Step11 uBR924(config-if)# no ip route-cache Remove the high-speed switching caches for IP
routing.
Step12 uBR924(config-if)# cable modem compliant bridge Enable DOCSIS-compliant bridging.
Step13 uBR924(config-if)# bridge-group bridge-group Assign the cable interface to the same bridge
spanning group used for the Ethernet interface.
Step14 uBR924(config-if)# bridge-group bridge-group
spanning-disabled
Disable the spanning tree on the cable interface .
Step15 uBR924(config-if)# Ctrl-Z Return to privileged EXEC mode.
Step16 uBR924# copy running-config startup-config Save the configuration to nonvolatile RAM.
Step17 uBR924# show startup-config Display the configuration file that was just created.