[c-nsp] bgp advertisement-interval

[Jon Lewis]

On Sat, 31 Jan 2009, Oliver Boehmer (oboehmer) wrote:

>>> When/why did this change?  Have other vendors done this?  A quick
>>> search suggests JunOS defaults to 30s for external peers and 5s for
>>> internal...but I don't know how current the documentation I found is.
>>
>> Never mind.  I'm not sure what I was seeing this morning, but what I
>> thought I was seeing isn't happening now.
>
> not sure what you saw, but IOS did change the default MRAI to zero
> seconds on iBGP and VRF eBGP (PE-CE) sessions (CSCsb09852/CSCsd98763)..

That's probably where I saw it...an iBGP session.  The reason I was 
looking at this is that recently we noticed one of our transit providers 
was sending us huge numbers/frequency of bgp updates, to the point that it 
appeared to be degrading performance on a sup720-3bxl.  While 
troubleshooting what was going on, the sup720 actually crashed and 
reloaded.  Later, watching show ip bgp neighbor, it was clear this 
provider had our session set to an MRAI of zero.  Initially, they denied 
this and said it was set to the default of 30s...but eventually they did 
admit that it wasn't set that way and changed their config.  I believe 
they're running Juniper gear.  Some searching suggests JunOS doesn't 
do a MRAI for eBGP by default.  I wonder if they switched gear recently, 
modified their config recently, or if it was just this router's "time to 
crash" and the flood of bgp updates is what pushed it over the edge.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________