Users Guide

• Enable graceful restart for the BGP node.
CONFIG-ROUTER-BGP mode
bgp graceful-restart
• Set maximum restart time for all peers.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [restart-time time-in-seconds]
The default is 120 seconds.
• Set maximum time to retain the restarting peer’s stale paths.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [stale-path-time time-in-seconds]
The default is 360 seconds.
• Local router supports graceful restart as a receiver only.
CONFIG-ROUTER-BGP mode
bgp graceful-restart [role receiver-only]
Filtering on an AS-Path Attribute
You can use the BGP attribute, AS_PATH, to manipulate routing policies.
The AS_PATH attribute contains a sequence of AS numbers representing the route’s path. As the route traverses an AS, the ASN is
prepended to the route. You can manipulate routes based on their AS_PATH to aect interdomain routing. By identifying certain ASN in the
AS_PATH, you can permit or deny routes based on the number in its AS_PATH.
AS-PATH ACLs use regular expressions to search AS_PATH values. AS-PATH ACLs have an “implicit deny.” This means that routes that do
not meet any Match lter are dropped.
To congure an AS-PATH ACL to lter a specic AS_PATH value, use these commands in the following sequence.
1 Assign a name to a AS-PATH ACL and enter AS-PATH ACL mode.
CONFIGURATION mode
ip as-path access-list as-path-name
2 Enter the parameter to match BGP AS-PATH for ltering.
CONFIG-AS-PATH mode
{deny | permit} filter parameter
This is the lter that is used to match the AS-path. The entries can be any format, letters, numbers, or regular expressions.
You can enter this command multiple times if multiple lters are desired.
For accepted expressions, refer to Regular Expressions as Filters.
3 Return to CONFIGURATION mode.
AS-PATH ACL mode
exit
4 Enter ROUTER BGP mode.
CONFIGURATION mode
router bgp as-number
Border Gateway Protocol IPv4 (BGPv4)
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