Persistent BGP peer flapping - do you care?

Susan Hares skh at
Thu Jan 17 19:27:25 UTC 2002


We are finalizing a revision of the BGP specification.  It is in
last call for your new BGP specification.

This BGP revision is to match the bgp in deployment.
One part of the specification remains, a fix for a problem called
  "persistent bgp flapping".   We urgently need input from nanog folks
on what is deployed.

Here's the description "presistent bgp flapping"
from the BGP specification:

 >If a BGP speaker detects an error, it shuts down the connection
 >and changes its state to Idle. Getting out of the Idle state
 >requires generation of the Start event.  If such an event is
 >generated automatically, then persistent BGP errors may result
 >in persistent flapping of the speaker.

1) Do any of the ISPs see the persistent bgp peer flapping now?

    Does anyone from the ISP community ever experience
    anything like this BGP persistent peer flapping?
    The solution is to have an exponential backoff in
    the rate of sending the Opens.

    If you have seen this, how many routers did this persistent
    bgp peer flapping impact?  (Can you give a % of your routers or a
    total number)?   How often does this impact your routers?

2) Is this feature on in your machine by default?
    If not, do you configure the exponential rates?

  3)Do you track if your routers are in this state?
    How do you track if your routers are in this state?

Sue Hares

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