Cisco Systems 78-11741-02 Configuring Basic BGP Features

Configuring BGP
Configuring Basic BGP Features
IPC-297
Cisco IOS IP Configuration Guide
Configuring Basic BGP Features
The tasks described in this section are for configuring basic BGP features.
Enabling BGP Routing
To enable BGP routing and establish a BGP routing process, use the following commands beginning in
global configuration mode:
Note For exterior protocols, a reference to an IP network from the network router configuration command
controls only which networks are advertised. This behavior is in contrast to IGP, such as IGRP, which
also use the network command to determine where to send updates.
Note The network command is used to inject IGP routes into the BGP table. The network-mask portion of
the command allows supernetting and subnetting. The resources of the router, such as configured
NVRAM or RAM, determine the upper limit of the number of network commands you can use.
Alternatively, you could use the redistribute router configuration command to achieve the same
result.
Configuring BGP Neighbors
Like other EGPs, BGP must completely understand the relationships it has with its neighbors. Therefore,
this task is required.
BGP supports two kinds of neighbors: internal and external. Internal neighbors are in the same
autonomous system; external neighbors are in different autonomous systems. Normally, external
neighbors are adjacent to each other and share a subnet, while internal neighbors may be anywhere in
the same autonomous system.
To configure BGP neighbors, use the following command in router configuration mode:
See the “BGP Neighbor Configuration Examples” section at the end of this chapter for an example of
configuring BGP neighbors.
Command Purpose
Step1 Router(config)# router bgp as-number Enables a BGP routing process, which places the
router in router configuration mode.
Step2 Router(config-router)# network network-number [mask
network-mask] [route-map route-map-name]
Flags a network as local to this autonomous system
and enters it to the BGP table.
Command Purpose
Router(config-router)# neighbor {ip-address | peer-group-name}
remote-as as-number
Specifies a BGP neighbor.