Installation guide

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Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
OL-2238-03
Chapter 4 Configuring Basic Broadband Internet Access
Integrated Routing and Bridging Configuration
Note IRB operation is supported only when using Cisco IOS Release 12.1(7)EC or greater. For complete
details on transparent bridging and IRB operation, see the Bridging chapters in the Cisco IOS Bridging
and IBM Networking Configuration Guide, Release 12.1, available on CCO and the Documentation
CD-ROM.
The following sample configuration file configures the Cisco uBR7111 router for basic IRB operation
with the following features:
• Basic DOCSIS Internet Access using IRB operations—This requires the following:
– IRB bridging is enabled.
– The FastEthernet and cable interfaces are assigned to the same bridge group.
– An IP address is configured only on the virtual BVI interface. No IP address is configured on
any physical interface.
– The subscriber-loop-control bridging option is enabled on the cable interface to allow packets
received on an upstream to be forwarded to another cable modem host on the downstream.
– The virtual BVI interface is configured with an IP address.
Note The spanning-tree protocol is disabled, by default, on the cable interface, but this is not
required.
• DOCSIS Cable Modem Configuration Files—These configuration files provide several different
service level options:
– platinum.cm—Users are given a maximum upstream bandwidth of 128kbps, with a guaranteed
minimum bandwidth of 10kbps. The downstream has a maximum bandwidth of 10Mbps. Up to
8 PCs are allowed on this connection.
– gold.cm—Users are given a maximum upstream bandwidth of 64kbps and a maximum
downstream bandwidth of 5Mbps. Up to 3 PCs are allowed on this connection.
– silver.cm—Users are given a maximum upstream bandwidth of 64kbps and a maximum
downstream bandwidth of 1Mbps. Only 1 PC is allowed on this connection.
– disable.cm—Users are denied access to the cable network. This configuration file can be used
for users who have cancelled service or have not paid their bills.
• TFTP server provides access to the cable modem configuration files (but a DHCP server is not
supported in bridging mode)
The following is a typical configuration file for IRB operation:
!
version 12.1
no service pad
service timestamps debug datetime msec localtime
service timestamps log datetime
no service password-encryption
service udp-small-servers max-servers no-limit
service tcp-small-servers max-servers no-limit
!
hostname ubr7100
!
logging buffered 409600 debugging
no logging console
!