MPLS default route weirdness

[Steven Mills]

Hello,

I currently have two ASRs back to back with MPLS enabled and an Internet service connected to the primary ASR. The internet service terminates inside of a VRF where I am receiving a default route via BGP from my ISP.

ISP(2.2.2.2/30)<--->(2.2.2.1/30)ASR1(10.10.10.1/30)<--->(10.10.10.2/30)ASR2

ASR1 Loopback = 1.1.1.1/32

ASR2 Loopback = 1.1.1.2/32

The routing table on ASR2 shows a default route via ASR1 and a summary route of my public IP range:

ASR2#show ip route vrf internet

Gateway of last resort is 10.10.10.1 to network 0.0.0.0

B*    0.0.0.0/0 [200/0] via 10.10.10.1, 00:35:33
      1.1.1.0/24 is variably subnetted, 2 subnets, 2 masks
B        1.1.1.0/24 [200/0] via 10.10.10.1, 00:35:33
C        1.1.1.2/32 is directly connected, Loopback1

However I am only able to ping ASR2s loopback (1.1.1.2) if I source the ping from ASR1s loopback (1.1.1.1) which is seen as part of a summary route, if I source the ping from ASR1s Internet facing interface (2.2.2.1) or a host on the Internet, it fails.

I can only get ping responses back if I use a source address that has a more specific route in the routing table of ASR2 than the default. If I ping an internet host from ASR

Any ideas on how to go about troubleshooting this issue? I created an access list that matched 1.1.1.2 and did a debug ip packet while I tried to ping from ASR2 to 8.8.8.8, I do not get a response but I do get output which indicates the packet is being forwarded. I ran the same debug on ASR1 at the same time but sawe no output.

Thanks,

Steve

[Steven Mills]

I am guessing the defaullt route should be showing up?

ASR2#sh mpls forwarding-table vrf internet
Local      Outgoing   Prefix           Bytes Label   Outgoing   Next Hop
Label      Label      or Tunnel Id     Switched      interface
20         Pop Label  1.1.1.2/32[V]   \
                                       0             aggregate/internet

[Jon Marshall]

Steve

To be honest i would have thought it would not just be the default but also the loopback of ASR1 which as you say is also not showing up.

Unfortunately i can't lab this up as i don't have anything to do it with.

The fact that when you ping from ASR2 to the internet and see traffic leaving but don't see anything on ASR1 suggests there is an issue with how the MPLS part is working but i can't see what it is at the moment.

I'll have a dig around to see if there is anything obvious.

Couple of questions -

1) before you set up the VPN part did you get the MPLS part working properly ?

2) i'm sure there is but is there a reason you need to run MPLS between the ASRs rather than simply allocating the interfaces connecting the ASRs into the VRF ?

Jon