[c-nsp] MPLS Label stack depth and MTU

[Gert Doering]

Hi,

On Tue, Apr 29, 2008 at 09:11:15AM -0700, Christopher Hunt wrote:
> I should have specified that links b,c and d are provided by local fiber 
> providers (PUDs, telcos, etc.) and are not under our direct control.  
> They are adding the VLAN tags.

Underlying transport headers are not relevant for MPLS MTU considerations
(in IOS, I seem to remember that some versions of JunOS *do* take them into
account).

Most likely "something in the path" is not really big-MTU compliant - 
you'll need to ping hop-by-hop and PE-PE (to start the search) with
df-bit set, as in

  cisco# ping mynexthop size 1526 df-bit

(and this requires "ip mtu" to be the same as "mpls mtu" on the link,
otherwise the result won't say anthing about MPLS MTU)

gert

-- 
USENET is *not* the non-clickable part of WWW!
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
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