[c-nsp] Problems with dot1q trunk over EoMPLS with WS-X6148-GE-TX

[Heath Jones]

Im not sure if it helps, but I remember having a lot of trouble back doing
DSL stuff - similar issues. There was a command: 'ip tcp mss-adjust' or
something similar - might be worth having a look at..



On 8 August 2010 12:02, Marco Matarazzo <marmata at gmail.com> wrote:

> Hi all,
>
> was trying to configure an EoMPLS link between two 6500s:
>
> Router1
> 6506 w/VS-S720-10G IOS 12.2(33)SXI2
> Customer facing blade: WS-X6148-RJ-45
>
> Router2
> 6503 w/WS-SUP32-10GE-3B IOS 12.2(33)SXI2
> Customer facing blade: WS-X6148-GE-TX
>
> The routers are connected between via the Sup integrated 10Gb interface,
> mtu
> on them is 9000.
>
> EoMPLS works fine if there's no dot1q trunk going over the VC. If there's
> one set, everything SEEMS to work, pings go thru, dns requests are fine, I
> can access any vlans from anywhere etc. Problems is with that I cannot
> access any internet page of downloading anything, all the connections
> stall!
> Seems like a MTU problem to me so begin troubleshooting and find that the
> maximum packet size that can travel between this dot1q trunk over EoMPLS is
> 1496 instead of 1500.
>
> On both routers of course the VC is up:
>
> Router1#sh mpls l2 vc
>
> Local intf     Local circuit              Dest address    VC ID      Status
> -------------  -------------------------- --------------- ----------
> ----------
> Fa2/32         Ethernet                   x.y.z.56   71172104   UP
>
> Router2##sh mpls l2 vc
>
> Local intf     Local circuit              Dest address    VC ID      Status
> -------------  -------------------------- --------------- ----------
> ----------
> Gi2/3          Ethernet               x.y.z.40   71172104   UP
>
> And the MTU of the VC is 1500:
>
> Router1##sh mpls l2 vc 71172104 det
> Local interface: Fa2/32 up, line protocol up, Ethernet up
>  Destination address: x.y.z.56, VC ID: 71172104, VC status: up
>    Output interface: Te5/5, imposed label stack {700}
>    Preferred path: not configured
>    Default path: active
>    Next hop: x.y.z.14
>  Create time: 03:32:35, last status change time: 03:32:35
>  Signaling protocol: LDP, peer x.y.z.56:0 up
>    Targeted Hello: x.y.z.40(LDP Id) -> x.y.z.56
>    MPLS VC labels: local 969, remote 700
>    Group ID: local 0, remote 0
>    MTU: local 1500, remote 1500
>    Remote interface description: -VC-71172104--
>  Sequencing: receive disabled, send disabled
>  VC statistics:
>    packet totals: receive 1959291, send 3518574
>    byte totals:   receive 1809500293, send 700321865
>    packet drops:  receive 0, send 0
>
> Router2##sh mpls l2 vc 71172104 det
> Local interface: Gi2/3 up, line protocol up, Ethernet up
>  Destination address: x.y.z.40, VC ID: 71172104, VC status: up
>    Output interface: Te1/2, imposed label stack {969}
>    Preferred path: not configured
>    Default path: active
>    Next hop: x.y.z.13
>  Create time: 3d19h, last status change time: 03:30:59
>  Signaling protocol: LDP, peer x.y.232.40:0 up
>    Targeted Hello: x.y.z.56(LDP Id) -> x.y.z.40
>    MPLS VC labels: local 700, remote 969
>    Group ID: local 0, remote 0
>    MTU: local 1500, remote 1500
>    Remote interface description: -VC-71172104--
>  Sequencing: receive disabled, send disabled
>  VC statistics:
>    packet totals: receive 50349195, send 5715589
>    byte totals:   receive 10440236044, send 5129079765
>    packet drops:  receive 0, send 0
>
> This is the port config:
>
> Router1#sh run int fa 2/32
> Building configuration...
>
> Current configuration : 245 bytes
> !
> interface FastEthernet2/32
>  description -VC-71172104--
>  no ip address
>  ip verify unicast source reachable-via any allow-default
>  no ip redirects
>  no ip proxy-arp
>  xconnect x.y.z.56 71172104 encapsulation mpls
>
> Router2##sh run int gi 2/3
> Building configuration...
>
> Current configuration : 257 bytes
> !
> interface GigabitEthernet2/3
>  description -VC-71172104--
>  no ip address
>  ip verify unicast source reachable-via any
>  no ip redirects
>  no ip proxy-arp
>  speed 100
>  duplex full
>  xconnect x.y.z.40 71172104 encapsulation mpls
>
>
> Unfortunately I cannot bump up the mtu on WS-X6148-GE-TX (need the A
> version
> for that!), but this is the port where the xconnect is terminating, so I
> was
> under the impression that I wouldn't need jumbo frames support as the
> labels
> would just be  passed thru the TenG mpls enabled interfaces, isn't it? I
> verified that lowering the interface mtu of the client machines makes
> everything work again. Played with the mpls mtu command, but it does not
> seem to have any effect whatsoever.
> Oddly enough, I see giants increasing on Router1, but not on Router2. I
> assume these are the dot1q trunk packets, but then why I'm seeing the
> counter increasing only on one side? The customer says on his switch
> interfaces, the mtu is 1500 on both trunks.
> So do you think I really need to bump the blade to at least WS-X6148A-GE-TX
> for this config to work, or am I missing something else?
>
> Thanks!
> ]\/[arco
> --
> I'm Winston Wolf, I solve problems.
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