Compatible Systems 5.4 manual BGP Route Maps Editor Dialog Box, BGP 269

Chapter 16 - BGP 269

The BGP Peer String specifies a BGP peer for this router. The BGP Peer String has the following syntax:

OnOff <IP Address> < AS Number> <Peer Config ID>

•On/Off

This parameter determines whether the router will try to establish a BGP session with the peer at start-up.

If this parameter is set to Off, the peer will not be contacted at start-up. The router can still establish a BGP session with this peer when the BGP Enable box is checked (in the BGP General Dialog Box). However, the next time the router is booted, the peer will come up in the Off state.

•IP Address

This specifies the IP address of the interface which will be a BGP peer for this router. The router will contact the peer using this IP address. The router must have the network of the supplied IP address in its routing table in order for the session to be established.

External peers should be directly connected to the router (usually over a WAN link). Internal peers do not need to be directly connected.

•AS Number

This specifies the number of the Autonomous System (AS) of the BGP peer. The router determines if a peer is internal or external based on the AS number of the peer, since internal peers have the same AS number as the router itself.

•Peer Config ID

This optional parameter specifies the number of the BGP Peer Configu- ration to which this peer will belong. A BGP Peer Configuration may be used for more than one peer only if all the same parameters are desired. BGP Peer Configuration is done using the BGP Peer Config Dialog Box.

BGP Route Maps Editor Dialog Box

Route maps help the administrator influence the route selection process. BGP uses weight, preference, and multi-exit discriminator (MED), among other things, to determine the optimal route. BGP uses the following criteria, in the order presented to select its best route for a destination.

•The most preferred path is the path with the largest weight.

•If the weights are the same, the protocol selects the path with the largest local preference.