FTOS Configuration Guide for the C-Series - Force10 Networks

• Enable route flap dampening
• Change BGP timers
• BGP neighbor soft-reconfiguration
• Route map continue
Enable BGP
By default, BGP is not enabled on the system. FTOS supports one Autonomous System (AS) and you must
assign the AS Number (ASN). To establish BGP sessions and route traffic, you must configure at least one
BGP neighbor or peer.
In BGP, routers with an established TCP connection are called neighbors or peers. Once a connection is
established, the neighbors exchange full BGP routing tables with incremental updates afterwards. In
addition, neighbors exchange KEEPALIVE messages to maintain the connection.
In BGP, neighbor routers or peers can be classified as internal or external. External BGP peers must be
connected physically to one another (unless you enable the EBGP multihop feature), while internal BGP
peers do not need to be directly connected. The IP address of an EBGP neighbor is usually the IP address
of the interface directly connected to the router. First, the BGP process determines if all internal BGP peers
are reachable, and then it determines which peers outside the AS are reachable.
Note: Sample Configurations for enabling BGP routers are found at the end of this chapter.
Use these commands in the following sequence, starting in the CONFIGURATION mode to establish BGP
sessions on the router.
Step Command Syntax Command Mode Purpose
1 router bgp as-number CONFIGURATION Assign an AS number and enter the
ROUTER BGP mode.
AS Number: 0-65535 (2-Byte) or
1-4294967295 (4-Byte)
Only one AS is supported per system
1a bgp four-octet-as-support CONFIG-ROUTER-
BGP
If you enter a 4-Byte AS Number, 4-Byte AS Support is enabled
automatically.
Enable 4-Byte support for the BGP
process.
Note: This is an OPTIONAL command.
You only need to enable if you want to
use 4-Byte AS numbers.
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