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

[Emanuel Popa]

hi,

we are using as border router a cisco 7613 with sup720-3bxl,
WS-X6724-SFP+DFC linecards and WS-X6704-10GE+DFC linecards.

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.

this border router also receives the full routing table from four
other upstream providers. the RP CPU is pretty overloaded and we are
planning an upgrade for this machine but this is not the main issue
right now.

we thought that the problem comes from the BGP configuraton on the
provider side, but we tried the same upgrade with another provider and
we have the same kind of problem.

i was wondering if any of you had the same problem and if you can
share the workarounds.

have a nice day,
emanuel