[c-nsp] Cogent IOS upgrade == BGP-3, "update malformed"

[randal k]

On Mon, Aug 23, 2010 at 6:34 AM, Zoe O'Connell <zoe-nsp at complicity.co.uk>wrote:

> On 23/08/10 13:07, Florian Weimer wrote:
> Yes, that's the conclusion we came to as well when we had it. (Luckily,
> it was an iBGP link to a firewall so easier to troubleshoot than a
> customer link). As far as I can recall, without Capability Negotiation
> it can't send 4-byte ASNs and some devices have a bug or differing RFC
> interpretation that means they can't handle being on the receiving end
> properly - if Cogent won't change their end, an IOS upgrade on the
> original psoters end should resolve it. I'm sure I sent a mail to
> someone about it at the time with more precise detail, but I can't seem
> to find it now.
>

Yep, we did an IOS upgrade from what we had forever (12.4(25)c) to the
latest tech train (12.4(24)T3 - and the feature nav says it has support) so
that we could get 4-byte ASN support; (12.4(24)T3); same config, and it
didn't resolve the issue. I am under the impression that 4-byte support is
automatically negotiated, and isn't "turned on," as it works elsewhere.

I think that there is some merit to the "dont-capability-negotiate" command,
but I'm afraid that is going to take out all normal capabilities, like route
refresh & soft in/out, etc; this also appears to be semi-undocumented by
Cisco, which makes that a little dicey to me.

That said, our resolution was to get Cogent to downgrade so that we can keep
buying their service. They are already chomping at the bit to re-upgrade
though ...

RK****