[c-nsp] MPLS MTU

[Frank Cisco]

Hi David,

Thanks for the URL.
Currently we've deployed our MPLS using mpls mtu 1524 on all interfaces
(mixed environment, some FE and some GE). For deploying EoMPLS let say for
one point-to-point, should we change end-to-end PE/P to mpls mtu
1530 and leave other PE still using 1524 ?   Need advise on it.


Frank


On 11/15/06, David Freedman <david.freedman at uk.clara.net> wrote:

I would recommend taking at look at this post I made
earlier in the year which summarised some responses from the list:

http://puck.nether.net/pipermail/cisco-nsp/2006-June/031765.html

Dave.

Sergio D. wrote:
> Hello folks,
>
> Some of our customers recently ran into some problems browsing and
> pinging with over 1468. We fixed the browsing issue by adjusting MSS
> on the incoming interfaces. It turns out that our core tag-switching
> interfaces were set at the default 1500 which in turn allowed only a
> 1496 or 1492 IP payload depending on how many labels.
> So now we are changing the MPLS mtu to 1508, but on Cisco's website
> it mentions the following :
> "Setting the MPLS MTU to a high number can lead to packets being
> dropped on some devices, because the labeled packet is larger than the
> interface physical MTU."
>
> A lot of our core is FE interfaces, I don't have a way to test this
> before, wouldn't just automatically raise the physical MTU?
> So after raising this an FE MTU goes to 1526? 1508 MPLS + 18 Vlan +
> ethernet header?
> Thanks,
>