[c-nsp] MPLS Issue

[David Freedman]

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?)

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)

Dave.