The MPLS-OPS Archive

["rajesh" <rajesh.chauhan@estelcom.com>]

Dear Friends

 

I need some clarification in MPLS over GRE Tunnels. Actually What I have observed while testing in my network that if GRE Tunnel starts from the same PE router from which VC starts, we need to disable and then re-enable dcef on GRE tunnel as well as on the interface where CPE is connected, otherwise packets drops at the VC. I have done this practice many times in my testing over GRE tunnels, but sometimes it doesn't work in this way, even after doing above mentioned step , packets drops at VC at both end.

 

I wanted to know the route cause behind this behaviour. I am not able to conclude the exact requirement for such secnario.

 

Here is the scenario ( Eompls)-

 

1. CE-1----------------------> PE-1=====================PE-2-------------------------> CE-2

                                          <----------GRE TUNNEL----------->

                                <---------------------------VC------------------------------>

 

In above scenario, I got success after doing the above config. ( In both cases Eompls as well as Frame-relay over MPLS)

 

 

2. CE-1---------------> PE-1--------------------P=====================PE-2-------------------------> CE-2

                                                         <----------GRE TUNNEL----------->

                                <----------------------------------------VC------------------------------>

 

In this case after doing the required changes , packets are going from CE-1 to CE-2 , but Packets are not coming back, they are droping at VC (i.e. not switching on to Tunnel).

 

PE-1= [C- 7500 & IOS = 12.0(26)S1 ]

PE-2= [C-7500 & IOS  = 12.0(25)S1 ]

P    =  [C-7500 & IOS  = 12.0(25)S1 ]

 

 

Thanks

Rajesh