Specifications

Configuring Bridging
Bridging and Routing Features for the Cisco uBR904 Cable Modem 13
Configuring Bridging
The Cisco uBR904 cable modem is configured for 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 modem to factory default settings, see the section
“Reestablishing Plug-and-Play Bridging” on page 15 for details. To reconfigure the cable modem
manually, perform the following tasks, starting in global configuration mode:
Step Command Purpose
1
uBR904(config)#no service pad
Disable packet assembler/disassembler
commands; prevent the uBR904 from accepting
incoming or outgoing Packet
Assembler/Disassembler (PAD) connections.
2
uBR904(config)#no service
password-encryption
Disable password encryption.
3
uBR904(config)#no ip routing
Disable IP routing on the uBR904.
4
uBR904(config)#interface Ethernet0
Enter interface configuration mode for the
Ethernet0 interface.
5
uBR904(config-if)#no ip route-cache
Disable high-speed switching caches for IP
routing.
6
uBR904(config-if)#bridge-group
bridge-group
Assigns the Ethernet0 interface to a bridge group.
The bridge group must be an integer between 1
and 63.
7 uBR904(config-if)#bridge-group
bridge-group spanning-disabled
Disable spanning tree on the Ethernet interface.
8
uBR904(config-if)#end
uBR904(config)#interface cable-modem0
Exit interface configuration mode for the
Ethernet0 interface and enter interface
configuration mode for the cable modem interface.
9
uBR904(config-if)#no ip address
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 modem
each time it connects to the network.
10
uBR904(config-if)#no ip route-cache
Disable high-speed switching caches for IP
routing on the cable interface.
11
uBR904(config-if)#no keepalive
Disable keepalives on the cable interface.
12
uBR904(config-if)#bridge-group
bridge-group
Assign the cable modem interface to a bridge
group. The bridge group must be an integer from 1
to 63. (The default is 59.)
13
uBR904(config-if)#bridge-group
bridge-group spanning-disabled
Disable spanning tree on the cable interface.
14
uBR904(config-if)#end
uBR904(config)#ip classless
Exit interface configuration mode.
(Optional) At times, the uBR904 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.
15
uBR904(config)#line console 0
Enter line configuration mode to configure the
console port.