[c-nsp] Sup2T MPLS-TE - Strange issue with MTU selection

[Adam Vitkovsky]

Hey James,

> From: James Jun [mailto:james at towardex.com]
> Sent: 18 May 2015 15:55
> Hey Adam,
> 
> On Mon, May 18, 2015 at 02:24:00PM +0000, Adam Vitkovsky wrote:
> 
> [ snip ]
> 
> > Can't this misbehaviour be worked around by configuring "mpls mtu" on
> the interface?
> > Just try putting it in there though you won't even see it in "sh run" output if
> the value is the same as interface mtu.
> 
> Yup, that was the very first thing I tried; mpls mtu 9216 (and anything bigger
> than 1500) had no effect.
> 
> Also, it's pretty strange -- if I signal an LSP thru this Cat6500 acting as P (in
> other words, asr1001-x and MX960 aside from 6500 and I signal a TE LSP
> between the asr and MX going thru this 6500), the maximum MTU that PEs
> will see becomes reduced to 1496 anytime this 6500 is involved in the path.
> 
> Strange eh?  I'm going to try removing the 6704-10ge card to see if it makes
> any difference, as that's the only change I can recall before this issue started
> happening.
> 
> Best,
> James
That's strange indeed I guess the card was added while the box was running right?
I'm thinking whether restart of the chases would clear the problem.
I'm also worried that once the card is removed the MTU will remain messed up.

adam
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