--> BGP Fast Fallover allows the router to terminate the bgp session as soon as the interface goes down.
--> If BGP Fast Fallover is not enabled on the router then the router will wait for hold down time to expire before tearing the bgp session.
--> This Feature only works for Directly connected EBGP Peers.
With BGP Fast Fallover
Step1 : Enable BGP Fast FallOver.
R1(Config)# router bgp 100
R1(Config-router)# bgp fast-external-failover
R1(Config-router)# exit
Step 2: Now shutdown the interface where EBGP neighbor is connected.
R1(config)# interface serial 1/0
R1(config-if)# shutdown
%LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial10/0, changed state to down
%BGP-5-ADJCHANGE: neighbor 192.168.1.2 Down Interface flap
Without BGP Fast Fallover
--> If BGP Fast Fallover is not enabled on the router then the router will wait for hold down time to expire before tearing the bgp session.
--> This Feature only works for Directly connected EBGP Peers.
With BGP Fast Fallover
Step1 : Enable BGP Fast FallOver.
R1(Config)# router bgp 100
R1(Config-router)# bgp fast-external-failover
R1(Config-router)# exit
Step 2: Now shutdown the interface where EBGP neighbor is connected.
R1(config)# interface serial 1/0
R1(config-if)# shutdown
%LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial10/0, changed state to down
%BGP-5-ADJCHANGE: neighbor 192.168.1.2 Down Interface flap
Without BGP Fast Fallover
Step1 : Disable BGP Fast FallOver.
R1(Config)# router bgp 100
R1(Config-router)# no bgp fast-external-failover
R1(Config-router)# exit
Step 2: Now shutdown the interface where EBGP neighbor is connected.
R1(config)# interface serial 1/0
R1(config-if)# shutdown
%LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial10/0, changed state to down
Check BGP neighbor table, the router will still show the neighbor in neighbor table untill hold down timer expires..
R1(Config)# router bgp 100
R1(Config-router)# no bgp fast-external-failover
R1(Config-router)# exit
Step 2: Now shutdown the interface where EBGP neighbor is connected.
R1(config)# interface serial 1/0
R1(config-if)# shutdown
%LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down
%LINEPROTO-5-UPDOWN: Line protocol on Interface Serial10/0, changed state to down
Check BGP neighbor table, the router will still show the neighbor in neighbor table untill hold down timer expires..
0 comments:
Post a Comment