Basic BGP configuration

Basic BGP Configuration Task List

The BGP configuration tasks are divided into basic and advanced tasks, which are described in the following sections. The basic tasks described in the first two sections are required to configure BGP; the basic and advanced tasks in the remaining sections are optional:

•Enabling BGP Routing (Required)

•Configuring BGP Neighbors (Required)

•Configuring BGP Interactions with IGPs (Optional)

•Configuring BGP Weights (Optional)

•Disabling Autonomous System Path Comparison (Optional)

•Configuring BGP Route Filtering by Neighbor (Optional)

•Configuring BGP Filtering Using Prefix Lists (Optional)

•Configuring BGP Path Filtering by Neighbor (Optional)

•Disabling Next Hop Processing on BGP Updates (Optional)

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:

	Command	Purpose
Step 1	Router(config)# router bgp as-number	Enables a BGP routing process, which places the router in router configuration mode.
Step 2	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.

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:

Command	Purpose
Router(config-router)# neighbor {ip-address | peer-group-name} remote-asas-number	Specifies a BGP neighbor.