[c-nsp] slow convergence for full bgp table on a Cisco 7613/SUP720-3BXL

[Saku Ytti]

On (2007-03-13 16:32 +0200), Emanuel Popa wrote:

> Here is the output:
> br01.frankfurt#sh int te 10/3 | i Input queue
>  Input queue: 0/75/109/109 (size/max/drops/flushes); Total output drops: 0

I see you tried incrasing it from another email and it didnt help.
You could try removing CoPP like Charles suggested, just to reduce
variables, make it as simple as possible.
If that doesn't help 'debug ip transactions' or even 'debug ip packet x'.
Or send control-plane traffic over SPAN for more comfortable debugging.

> But:
> 
> - routing protocol packets are not dropped when default hold queue of
> 75 is full; they are considered priority packets and they are dropped
> after headroom of 1000 is full; please see
> http://www.cisco.com/en/US/products/hw/routers/ps167/products_tech_note09186a008012fb87.shtml
> for more details
> 
> - PMTUD is enabled and we have a good data segment on this session:
> br01.frankfurt#sh ip bgp neighbors A.B.C.D | i segment
> Datagrams (max data segment is 1440 bytes):
> 
> Thanks,
> Emanuel
> 
> 
> On 3/13/07, Saku Ytti <saku+cisco-nsp at ytti.fi> wrote:
> >On (2007-03-13 15:50 +0200), Emanuel Popa wrote:
> >
> >> we had 2 x GE links with our upstream and one BGP session with full
> >> routing table on the loopback interfaces. everything was fine until we
> >> needed an upgrade. so we upgraded from 2 x GE to 1 x 10GE. our biggest
> >> issue is that our router needs around two hours to receive the full
> >> bgp table over the new session. the old session takes a maximum of
> >> five minutes to converge. the only difference is that one session ends
> >> on a 6724-SFP linecard and the other session ends on a 6704-10GE
> >> linecard. both of them have DFCs.
> >
> >Do you have input queue drops:
> >LAB-P1#sh int giga1/1 | i Input
> >  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
> >
> >If so, increase it, I can't think of any issue increasing it to maximum,
> >but perhaps 1000 for a start.
> >
> >btw. takes around minute for me, which is way too much and Cisco opened
> >case because they couldn't immediately explain what is capping the
> >convergency, CSCsh81034.
> >
> >You might also want to run PMTUD, but lack of it, can't cause
> >issues this severe.
> >
> >--
> >  ++ytti
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> >

-- 
  ++ytti