[c-nsp] MPLS Issue

[Steven Saner]

On Nov 9, 2010, at 11:36 AM, David Freedman wrote:

> Steven Saner wrote:
>> Hi all:
>>
>> I am admittedly fairly new to MPLS configurations. I am using it to
>> establish some VPNs between several routers. I am trying to turn up  
>> MPLS
>> between two routers that are currently in production with standard IP
>> routing with OSPF and BGP.
>>
>>   Router ---- MPLS ---- Router ------------ Router ---- MPLS ----  
>> Router
>>
>> All of the routers are 7200 VXR routers. MPLS is running between the
>> "left" two routers and the "right" two routers. When I try to turn  
>> MPLS
>> on between the middle two routers, all existing traffic stops between
>> them. This is a DS-3 link and I am simply adding the following to the
>> serial interfaces:
>>
>> mpls ip
>> mpls label protocol ldp
>>
>> As soon as I add these options on both sides, both routers report to
>> syslog that LDP Neighbor x.x.x.x is UP. But normal traffic stops. I  
>> can
>> no longer ping things from one side to the other. Is this to be
>> expected? Is there some synchronization that needs to take place? How
>> long should that be?
>>
>> Thank you for any suggestions.
>
> What protocol is running over the DS3, is it PPP? (i.e do you have to
> negotiate MPLSCP first?)

No, it is HDLC. PA-2T3 on each end.


>
> also, can you get output of "show mpls forwarding-table x.x.x.x" where
> x.x.x.x is an address you can not reach (from both sides)

Before I enable mpls:

Router A#sho mpls forwarding-table 10.160.0.140
Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
tag    tag or VC   or Tunnel Id      switched   interface
72     Untagged    10.160.0.0/16     0          Se6/0      point2point

Router B#sho mpls forwarding-table 207.178.96.65
Local  Outgoing      Prefix            Bytes Label   Outgoing   Next Hop
Label  Label or VC   or Tunnel Id      Switched      interface
67     No Label      207.178.96.64/26  0             Se6/0       
point2point

After I enable mpls and can no longer ping

Router A#sho mpls forwarding-table 10.160.0.140
Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
tag    tag or VC   or Tunnel Id      switched   interface
72     45          10.160.0.0/16     511928     Se6/0      point2point

Router B#sho mpls forwarding-table 207.178.96.65
Local  Outgoing      Prefix            Bytes Label   Outgoing   Next Hop
Label  Label or VC   or Tunnel Id      Switched      interface
67     39            207.178.96.64/26  0             Se6/0       
point2point


Thanks.

Steve


--
---------------------------------------------------------------
Steven Saner
steve at saner.net