BGP ~ Finite State Machine PT 2

I wanted to follow last nights blog on FSM with another more hands on FSM. I set up two routers, connected them via their f0/0 interfaces and configured a eBGP relationship.


ROUTER_1#sh bgp nei
BGP neighbor is 172.16.12.2, remote AS 2, external link
BGP version 4, remote router ID 172.16.12.2
BGP state = Established, up for 00:33:41

ROUTER_2#sh bgp nei
BGP neighbor is 172.16.12.1, remote AS 1, external link
BGP version 4, remote router ID 172.16.12.1
BGP state = Established, up for 00:34:28

Once up and working i issued the “debug bgp iv4 unicast” cmd and shut the f0/0 interface down on router one.


ROUTER_1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
ROUTER_1(config)#int f0/0
ROUTER_1(config-if)#shut
ROUTER_1(config-if)#
00:24:07: BGP: 172.16.12.2 resetting - interface FastEthernet0/0 down
00:24:07: BGPNSF state: 172.16.12.2 went from nsf_not_active to nsf_not_active
00:24:07: BGP: 172.16.12.2 went from Established to Idle
00:24:07: %BGP-5-ADJCHANGE: neighbor 172.16.12.2 Down Interface flap
00:24:07: BGP: 172.16.12.2 closing
00:24:09: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down
00:24:10: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

The neighbor relationship with router two goes straight from Established to Idle.
I then brought the interface back up.


ROUTER_1(config-if)#no shut
ROUTER_1(config-if)#exit
ROUTER_1(config)#exit
ROUTER_1#
00:24:36: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up
00:24:36: %SYS-5-CONFIG_I: Configured from console by console
00:24:38: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up
00:24:38: BGP: 172.16.12.2 went from Idle to Active
00:24:38: BGP: 172.16.12.2 open active delayed 27469ms (35000ms max, 28% jitter)
00:25:05: BGP: 172.16.12.2 passive open to 172.16.12.1
00:25:05: BGP: 172.16.12.2 went from Active to Idle
00:25:05: BGP: 172.16.12.2 went from Idle to Connect
00:25:05: BGP: 172.16.12.2 rcv message type 1, length (excl. header) 26
00:25:05: BGP: 172.16.12.2 rcv OPEN, version 4, holdtime 180 seconds
00:25:05: BGP: 172.16.12.2 went from Connect to OpenSent
00:25:05: BGP: 172.16.12.2 sending OPEN, version 4, my as: 1, holdtime 180 seconds
00:25:05: BGP: 172.16.12.2 rcv OPEN w/ OPTION parameter len: 16
00:25:05: BGP: 172.16.12.2 rcvd OPEN w/ optional parameter type 2 (Capability) len 6
00:25:05: BGP: 172.16.12.2 OPEN has CAPABILITY code: 1, length 4
00:25:05: BGP: 172.16.12.2 OPEN has MP_EXT CAP for afi/safi: 1/1
00:25:05: BGP: 172.16.12.2 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
00:25:05: BGP: 172.16.12.2 OPEN has CAPABILITY code: 128, length 0
00:25:05: BGP: 172.16.12.2 OPEN has ROUTE-REFRESH capability(old) for all address-families
00:25:05: BGP: 172.16.12.2 rcvd OPEN w/ optional parameter type 2 (Capability) len 2
00:25:05: BGP: 172.16.12.2 OPEN has CAPABILITY code: 2, length 0
00:25:05: BGP: 172.16.12.2 OPEN has ROUTE-REFRESH capability(new) for all address-families
BGP: 172.16.12.2 rcvd OPEN w/ remote AS 2
00:25:05: BGP: 172.16.12.2 went from OpenSent to OpenConfirm
00:25:05: BGP: 172.16.12.2 send message type 1, length (incl. header) 45
00:25:05: BGP: 172.16.12.2 went from OpenConfirm to Established
00:25:05: %BGP-5-ADJCHANGE: neighbor 172.16.12.2 Up
ROUTER_1#

You can see the FSM in action, nice!!!

BE.

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~ by bigevil on May 15, 2010.

 
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