[c-nsp] IS-IS Emergency

[Vinny Abello]

Jared Mauch wrote:
>> As far as the BGP convergence on start-up, you may also want to
>> investigate using "ip tcp path-mtu-discovery" in your configurations if
>> you don't have it already. Last I knew, the MTU defaults to a very low
>> size for BGP sessions. Adding this command will allow it to converge
>> faster as more data can be transmitted in each packet when your sessions
>> are coming up.
>>
>> Our ISIS configuration above that Robert provided was largely based on
>> the recommended settings from Cisco that were provided to AOL during
>> their OSPF to ISIS migration... maybe minus the ip fast-convergence.
>>
>> Our (Cisco) platforms are generally Cat6500 12.2(18)SXF and 7206
>> 12.2(28)SB builds.
> 
> 	Increasing the input hold queue to 4096 on the interfaces
> can also speed up convergence.  I usually don't bump them all the way
> up for fear of a wedge bug or something strange, so want to have
> some room to wiggle, but 3.5k should work for most folks nicely.
> 
> 	- Jared

That's another good tip, Jared. I actually do that as well as I've
noticed input drops on interfaces while BGP is coming up. I've also seen
input drops on interfaces of routers terminating a lot of L2TPv3 tunnels
due to the high packet count aimed at the RP, so this is standard
practice as well.

Have you just had fears of bugs with it set to 4096 or have you actually
been bitten by an issue?

-- 

Vinny Abello
Network Engineer
vinny at tellurian.com
(973)940-6100
PGP Key Fingerprint: 3BC5 9A48 FC78 03D3 82E0  E935 5325 FBCB 0100 977A

Tellurian Networks - The Ultimate Internet Connection
http://www.tellurian.com (888)TELLURIAN

"Courage is resistance to fear, mastery of fear - not absence of fear"
-- Mark Twain