[c-nsp] mpls ip creating traffic disturbance(s)

[Eric A Louie]

Tim - the default mtu is 1500.  According to "sh ip int", the mtu is 1500 
already.

cmt#sh ip int
FastEthernet1/0 is up, line protocol is up
  Internet address is 10.250.200.230/30
  Broadcast address is 255.255.255.255
  Address determined by non-volatile memory
  MTU is 1500 bytes


But when I show mpls int fa1/0 det the output is

Interface FastEthernet1/0:
        IP labeling enabled (ldp):
          Interface config
        LSP Tunnel labeling not enabled
        BGP tagging not enabled
        Tagging operational
        Optimum Switching Vectors:
          IP to MPLS Turbo Vector
          MPLS Turbo Vector
        Fast Switching Vectors:
          IP to MPLS Fast Switching Vector
          MPLS Turbo Vector
        MTU = 1524

Unfortunately, this output is from a c7206 running 12.4 and not an ME-3600X 
running 15.2

 Much appreciated, Eric




________________________________
From: Tim Warnock <timoid at timoid.org>
To: Eric A Louie <elouie at yahoo.com>
Sent: Tue, January 15, 2013 5:18:08 PM
Subject: RE: [c-nsp] mpls ip creating traffic disturbance(s)

Be sure to use:
ip mtu 1500
and
ipv6 mtu 1500
on every interface otherwise as your IGP grows you may run into breakage.

> -----Original Message-----
> From: Eric A Louie [mailto:elouie at yahoo.com]
> Sent: Wednesday, 16 January 2013 11:10 AM
> To: Tim Warnock
> Cc: Cisco NSP
> Subject: Re: [c-nsp] mpls ip creating traffic disturbance(s)
> 
> Tim - yes, over the link, I believe you're right.  The traffic was getting 
>affected
> even if it didn't traverse that link.
> 
> 
> Much appreciated, Eric
> 
> 
> ________________________________
> 
> From: Tim Warnock <timoid at timoid.org>
> To: Eric A Louie <elouie at yahoo.com>
> Sent: Tue, January 15, 2013 4:31:12 PM
> Subject: RE: [c-nsp] mpls ip creating traffic disturbance(s)
> 
> Hi Eric,
> 
> This will be caused by MTU.
> 
> > -----Original Message-----
> > From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-
> > bounces at puck.nether.net] On Behalf Of Eric A Louie
> > Sent: Wednesday, 16 January 2013 10:18 AM
> > To: Cisco NSP
> > Subject: [c-nsp] mpls ip creating traffic disturbance(s)
> >
> > We implemented what seemed to be a pretty simple mpls configuration to
> > test a
> > vrf config.
> >
> > It caused widespread havoc across my production network.
> >
> > Has anyone encountered a situation where they've put "mpls ip" on a link
> > and had
> > it cause problems with web browsing to the Internet, even on traffic that
> > passed
> > through the router that was not going through the mpls ip interfaces?
> >
> > I have a case open with Cisco TAC but was looking for some additional
> > guidance
> > and perhaps some experience around this strange problem.
> >
> >  Much appreciated, Eric
> > _______________________________________________
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