[c-nsp] 6500 IOS recommendation?

Ross Halliday ross.halliday at wtccommunications.ca
Wed Oct 23 11:17:09 EDT 2013

> A little word of advice for those that use BGP: Don't use 15.1(1)SY and
> 15.1(1)SY1.
> They have a nasty little BGP bug that can create black holes or loops
> for random prefixes due to stale RIB entries of withdrawals that are not
> processed correctly (CSCuh43027).
> Some withdrawn prefixes are being removed from the BGP table, but not from
> the RIB!
> It's very hard to debug and even notice as it usually only affects a
> couple thousand prefixes, but it's
> annoying.
> A lot of 15.1, 15.2. and 15.3 trains have the same issues, so be careful
> also on the 7600 "S" train.
> It is fixed in 15.1(2)SY and 15.2(4)S4 only.
> So if you want to use 15.1 on Sup720/Sup2T, use 15.1(2)SY.

A couple THOUSAND? Sheesh that's half of my IGP, I think I'd notice that! (in a few hours)

I don't have access to view the bug details, does this impact VPNv4 prefixes?


More information about the cisco-nsp mailing list