[c-nsp] ASR903 Service instance MTU

[Sigurbjörn Birkir Lárusson]

Yes, the MTU on the Physical interface needs to be at least as high as the MTU required on the Xconnect.

Be aware that the 903 (RSP1 and RSP2 at least, haven't tested with RSP3) can only support 6 different MTU values at the same time, so 5 custom values other than the default 1500.  Once you hit the limit (which will trigger a syslog message) the MTU command will simply not take affect and a seemingly random MTU value is applied in hardware.

Kind regards,
Sibbi

From: Mohammad Khalil <eng_mssk at hotmail.com<mailto:eng_mssk at hotmail.com>>
Date: Wednesday 11 November 2015 08:36
To: Spyros Kakaroukas <s.kakaroukas at connecticore.com<mailto:s.kakaroukas at connecticore.com>>, Lukas Tribus <luky-37 at hotmail.com<mailto:luky-37 at hotmail.com>>, "Sigurbjorn B. Larusson" <sigurbjornl at vodafone.is<mailto:sigurbjornl at vodafone.is>>, George Giannousopoulos <ggiannou at gmail.com<mailto:ggiannou at gmail.com>>
Cc: "cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>" <cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>>
Subject: RE: [c-nsp] ASR903 Service instance MTU

So I have to raise the MTU on the physical interface that holds the service instances and then raise it on the pseudwire interfaces?

> From: s.kakaroukas at connecticore.com<mailto:s.kakaroukas at connecticore.com>
> To: eng_mssk at hotmail.com<mailto:eng_mssk at hotmail.com>; luky-37 at hotmail.com<mailto:luky-37 at hotmail.com>; sigurbjornl at vodafone.is<mailto:sigurbjornl at vodafone.is>; ggiannou at gmail.com<mailto:ggiannou at gmail.com>
> CC: cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>
> Subject: RE: [c-nsp] ASR903 Service instance MTU
> Date: Tue, 10 Nov 2015 10:12:21 +0000
>
> Hi,
>
> You are correct. IIRC, changing the MTU on the pseudowire, changes just what
> you report as the MTU of the AC. Usually the parser will prevent you from
> doing something that won't work, or fix it for you, but I don't like to
> depend on that. Either way, you will have to at least increase the MTU on
> the ACs.
>
> My thoughts and words are my own.
>
> Kind Regards,
>
> Spyros
>
>
> -----Original Message-----
> From: cisco-nsp [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
> Mohammad Khalil
> Sent: Tuesday, November 10, 2015 9:17 AM
> To: Lukas Tribus <luky-37 at hotmail.com<mailto:luky-37 at hotmail.com>>; Sigurbjörn Birkir Lárusson
> <sigurbjornl at vodafone.is<mailto:sigurbjornl at vodafone.is>>; George Giannousopoulos <ggiannou at gmail.com<mailto:ggiannou at gmail.com>>
> Cc: cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>
> Subject: Re: [c-nsp] ASR903 Service instance MTU
>
> Thanks Lukas
> What am facing actually is that I got a request from my customer to raise
> the MTU for all his L2VPN connections (VFI,XCONNECT) AM afraid if I raised
> the MTU on the pseudowire interface while the physical interface MTU is
> still 1500 to cause an issue
>
> > From: luky-37 at hotmail.com<mailto:luky-37 at hotmail.com>
> > To: eng_mssk at hotmail.com<mailto:eng_mssk at hotmail.com>; sigurbjornl at vodafone.is<mailto:sigurbjornl at vodafone.is>; ggiannou at gmail.com<mailto:ggiannou at gmail.com>
> > CC: cisco-nsp at puck.nether.net<mailto:cisco-nsp at puck.nether.net>
> > Subject: RE: [c-nsp] ASR903 Service instance MTU
> > Date: Sun, 8 Nov 2015 19:00:14 +0100
> >
> > Hi Mohammad,
> >
> >
> > > Hi all
> > > I have discovered that I can change the MTU as the below syntax
> > > interface GigabitEthernet0/0/1 no ip address
> > >
> > > service instance 100 ethernet
> > > xconnect x.x.x.x {VC_ID} encapsulation mpls mtu {}
> > >
> > > But If I configured the below
> > > l2vpn xconnect context {NAME}
> > >
> > > There is no option for the MTU under it
> >
> >
> > You have to configure it on the pseudowire interface:
> > http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/mp_l2_vpns/configurat
> > ion/xe-3s/mp-l2-vpns-xe-3s-book/mp-any-transport-xe.html#concept_B3B08
> > 5AFF0384B5C867E3EF9A4C58564
> >
> >
> >
> > Lukas
> >
>
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