From: Greg Wendel (gwendel@gmail.com)
Date: Sat Jul 21 2007 - 14:33:55 ART
I found out how to recreate the jitter error message that was mentioned by
Mick Vaites on groupstudy back in 2006. This is running on a dynamips lab,
but I don't think this is relevant to the problem. Running (C3640-JK9S-M),
Version 12.4(12),
Here is a quick synopsis:
1. misconfigured routers with ttl-security command - caused error message
open active delayed 28366ms (35000ms max, 28% jitter)
2. Put ttl-security to correct values and the peering came up and the error
message went away.
Any other explanations would be appreciated.
One other question,
Networkers 2006 mentioned using the ttl-security with a higher value such as
254, but I cannot find my notes on this and am not sure how they were doing
this. Any ideas?
NOTES
Configuration of routers:
Router 1
router bgp 1000
no synchronization
bgp log-neighbor-changes
neighbor 150.1.3.3 remote-as 100
neighbor 150.1.3.3 ttl-security hops 250 (MISCONFIGURATION)
neighbor 150.1.3.3 update-source Loopback0
neighbor 150.1.5.5 remote-as 1000
neighbor 150.1.5.5 update-source Loopback0
no auto-summary
Router 3
router bgp 100
no synchronization
bgp log-neighbor-changes
network 221.221.221.0
neighbor 150.1.1.1 remote-as 1000
neighbor 150.1.1.1 ttl-security hops 250 (MISCONFIGURATION)
neighbor 150.1.1.1 update-source Loopback0
no auto-summary
!
!
At this point the BGP peer failed and debug ip bgp showed the output below:
Rack1R3#
*Mar 1 00:43:12.691: BGP: 150.1.1.1 open active, local address 150.1.3.3
*Mar 1 00:43:12.715: BGP: 150.1.1.1 open failed: Connection refused by
remote host, open active delayed 14937ms (16000ms max, 28% jitter)
I put ttl-security back to the actual number of hops by adding
neighbor 150.1.x.x ttl-security hops 2
and the peering came up and the jitter went away.
-- Gregory Wendel Springfield VA, 22153
This archive was generated by hypermail 2.1.4 : Sat Aug 18 2007 - 08:17:41 ART