Cisco ubr924 Installation And Startup page 21

Reconfigure the Router (continued)
!
line con 0
transport input none
line vty 0 4
!
end
Note: For most residential subscribers, DOCSIS-compliant bridging is the default—also referred to as
"plug-and-play" bridging.
The plug-and-play 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 Cisco uBR924
Cable Access Router Installation and Configuration Guide.
The Cisco uBR924 cable access router acts as a transparent bridge for up to four PCs directly connected to it.
Cisco IOS software treats all four of the router's Ethernet hub ports as one Ethernet interface.
Caution
The ability of the router to grant access to CPE devices is controlled by the "MAC CPE" field
in the DOCSIS configuration file. The Cisco uBR924 cable access router defaults to one CPE MAC
address unless this option is set to a higher number.
Basic Internet Access Routing Example
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 sample configuration file follows.
Note: The configuration file contains the no cable-modem compliant bridge command. This command disables
DOCSIS-compliant bridging. Also note the absence of the default bridge group 59 line from the Ethernet and cable 0
interfaces from that shown earlier. These lines must be removed if the unit is to act as a router. In addition, the routing
protocol must be configured. Applicable commands are in bold in the example that follows.
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