[j-nsp] L2VPN MTU Issue

[Diogo Montagner]

Hi Eric,

Can you check the mtu negotiated by the l2vpn ? (Use traceoptions)

What kind of pic are you using ? And what is the platform ?

Tks

On 9/29/10, Eric Van Tol <eric at atlantech.net> wrote:
> Hi all,
> I'm having an issue with an L2VPN customer at the moment. They need to be
> able to pass 1500-byte IP packets between two locations connected via an
> ethernet encapsulated L2VPN.  I am able to ping from PE to PE with 1500-byte
> sized packets with the df-bit set without a problem.  The L2VPN connection
> is up and the customer can get a max of 1490-bytes through without
> fragmentation.  My LSP shows an MTU of 1500:
>
> x.x.x.47
>   From: x.x.x.46, LSPstate: Up, ActiveRoute: 0
>   LSPname: xx_to_nn, LSPpath: Primary
>   Suggested label received: -, Suggested label sent: -
>   Recovery label received: -, Recovery label sent: 302048
>   Resv style: 1 FF, Label in: -, Label out: 302048
>   Time left:    -, Since: Tue Sep 28 12:35:29 2010
>   Tspec: rate 0bps size 0bps peak Infbps m 20 M 1500
>   Port number: sender 5 receiver 19901 protocol 0
>   PATH rcvfrom: localclient
>   Adspec: sent MTU 1500
>   Path MTU: received 1500
>   PATH sentto: x.x.x.131 (ge-1/3/0.0) 217 pkts
>   RESV rcvfrom: x.x.x.131 (ge-1/3/0.0) 215 pkts
>   Explct route: x.x.x.131 x.x.x.121 x.x.x.5 x.x.x.58 x.x.x.164
>   Record route: <self> x.x.x.131 x.x.x.121 x.x.x.5 x.x.x.58 x.x.x.164
> Total 2 displayed, Up 2, Down 0
>
> All interfaces *between* the PEs have the following config: IP MTU = 1500,
> MPLS MTU = 1512.  I have verified that the customer can hit their respective
> site's PE with 1500-byte packets by temporarily configuring each
> customer-facing interface with an appropriate IP address and pinging.
>
> Here's the pertinent configs of the two PEs:
>
> Side A:
>
> interfaces {
>     ge-0/0/1 {
>         description "Site A";
>         enable;
>         mtu 9192;
>         encapsulation ethernet-ccc;
>         unit 0 {
>             family ccc;
>         }
>     }
> }
> protocols {
>     rsvp {
>         interface ge-0/0/0.0;
>     }
>     mpls {
>         label-switched-path xx_to_nn {
>             to x.x.x.46;
>         }
>         interface ge-0/0/0.0;
>         interface ge-0/0/1.0;
>     }
>     ldp {
>         interface ge-0/0/0.0;
>     }
> }
> routing-instances {
>     cid-A {
>         instance-type l2vpn;
>         interface ge-0/0/1.0;
>         route-distinguisher x.x.x:3211;
>         vrf-import vpn-A-import;
>         vrf-export vpn-A-export;
>         protocols {
>             l2vpn {
>                 encapsulation-type ethernet;
>                 no-control-word;
>                 interface ge-0/0/1.0;
>                 site Side-A {
>                     site-identifier 1;
>                     interface ge-0/0/1.0 {
>                         remote-site-id 2;
>                     }
>                 }
>             }
>         }
>     }
> }
>
>
> Side B:
> interfaces {
>     fe-0/2/1 {
>         description "Site B";
>         enable;
>         mtu 9192;
>         encapsulation ethernet-ccc;
>         unit 0 {
>             family ccc;
>         }
>     }
> }
> protocols {
>     rsvp {
>         interface ge-1/3/0.0;
>     }
>     mpls {
>         label-switched-path nn_to_xx {
>             to x.x.x.47;
>         }
>         interface ge-1/3/0.0;
>         interface fe-0/2/1.0;
>     }
>     ldp {
>         interface ge-1/3/0.0;
>     }
> }
> routing-instances {
>     cid-A {
>         instance-type l2vpn;
>         interface fe-0/2/1.0;
>         route-distinguisher x.x.x:3211;
>         vrf-import vpn-A-import;
>         vrf-export vpn-A-export;
>         protocols {
>             l2vpn {
>                 encapsulation-type ethernet;
>                 no-control-word;
>                 interface fe-0/2/1.0;
>                 site Side-A {
>                     site-identifier 1;
>                     interface fe-0/2/1.0 {
>                         remote-site-id 2;
>                     }
>                 }
>             }
>         }
>     }
> }
>
> Does anyone see a problem with my configs here?  I seem to be losing 10
> bytes somewhere and it's driving me mad.
>
> -evt
>
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./diogo -montagner