[c-nsp] MPLS is not working

Peter Rathlev peter at rathlev.dk
Fri Feb 29 18:16:54 EST 2008


Hi Ahmed,

If you're running MPLS VPN you don't want the customer prefixes in your
MPLS forwarding table. PE to PE communications should use an LSP from
(global) loopback to loopback, and uses an underlying VPN label for the
VRF part. This means that the P router(s) won't have to know about
customer prefixes, which is a good thing. So your MPLS forwarding table
looks fine.

What does "show ip cef vrf CustormerA 170.5.0.0 255.255.0.0" show?

Do you have "no mpls ip propagate-ttl" in your configuration by the way?

Regards,
Peter


On Fri, 2008-02-29 at 16:45 -0500, Ahmed Mohamed wrote:
> Hello,
> 
> i used dynamips to perform a topology
>  the topology is as follows:
> 
> CEA-1<======>PE1-AS1<======>P1<======>PE2-AS1<======>CE2-A
> 
> <----------FR-----------><----------ppp-------><------ppp--------><-------FR--------->
> 
> <-------static----------><------OSPF--------><-----OSPF-----><------static------>
>                                 <----------------------TDP------------------->
>                                 <------------------i
> BGP--------------------->
> 
> i ping CE to PE good and vice verse on both ends
> PE to PE pings good, also PE to P
> 
> ping CE to CE is not working , not even pinging PE to remote CE
> 
> the vrf table looks perfect, all routes are in it
> i don't know what would be the cause of the problem,
> 
> below is the logs from my topology, thanks to advise:
> 
> 
> PE2-AS1#sh ip route
> Gateway of last resort is not set
> 
>      172.16.0.0/32 is subnetted, 2 subnets
> C       172.16.200.1 is directly connected, Loopback1
> O       172.16.100.1 [110/129] via 10.10.10.5, 02:04:26, Serial0/0
>      10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
> O       10.10.10.0/30 [110/128] via 10.10.10.5, 02:04:26, Serial0/0
> C       10.10.10.4/30 is directly connected, Serial0/0
> C       10.10.10.5/32 is directly connected, Serial0/0
> C       10.10.10.102/32 is directly connected, Loopback0
> O       10.10.10.101/32 [110/129] via 10.10.10.5, 02:04:26, Serial0/0
> <<---- PE1
> O       10.10.10.200/32 [110/65] via 10.10.10.5, 02:04:26, Serial0/0
> <<----- P1
> =============================================================================================
> 
> PE2-AS1#sh ip route vr CustomerA
> 
> Gateway of last resort is not set
> 
> B    170.1.0.0/16 [200/0] via 10.10.10.101, 02:03:37    <<<< remote CE
> network advertised via iBGP
> S    170.2.0.0/16 [1/0] via 172.16.2.2
> S    170.3.0.0/16 [1/0] via 172.16.2.2
> S    170.4.0.0/16 [1/0] via 172.16.2.2
> B    170.5.0.0/16 [200/0] via 10.10.10.101, 02:03:37    <<<< remote CE
> network advertised via iBGP
> B    170.6.0.0/16 [200/0] via 10.10.10.101, 02:03:37    <<<< remote CE
> network advertised via iBGP
>      172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks
> B       172.16.1.0/30 [200/0] via 10.10.10.101, 02:03:37
> C       172.16.2.0/24 is directly connected, Serial1/0
> =============================================================================================
> 
> PE2-AS1#sh tag forwarding-table
> Local  Outgoing    Prefix            Bytes tag  Outgoing   Next Hop
> tag    tag or VC   or Tunnel Id      switched   interface
> 16     Untagged    10.10.10.5/32     0          Se0/0      point2point
> 17     Pop tag     10.10.10.0/30     0          Se0/0      point2point
> 18     18          10.10.10.101/32   0          Se0/0      point2point
> 19     Pop tag     10.10.10.200/32   0          Se0/0      point2point
> 20     20          172.16.100.1/32   0          Se0/0      point2point
> 24     Aggregate   172.16.2.0/24[V] <http://172.16.2.0/24%5BV%5D>  0
> 25     Untagged    170.2.0.0/16[V] <http://170.2.0.0/16%5BV%5D>   0
> Se1/0      172.16.2.2
> 26     Untagged    170.3.0.0/16[V] <http://170.3.0.0/16%5BV%5D>   0
> Se1/0      172.16.2.2   <<<<< only loca networks in the tag forwarding table
> 27     Untagged    170.4.0.0/16[V] <http://170.4.0.0/16%5BV%5D>   0
> Se1/0      172.16.2.2
> =============================================================================================
> 
> CEA-2#ping 172.16.2.1
> 
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 172.16.2.1, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max = 8/16/24 ms
> 
> =============================================================================================
> 
> PE2-AS1#ping 10.10.10.101   <<<<<<< pinging remote PE1-AS1
> 
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 10.10.10.101, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max = 32/68/84 ms
> =============================================================================================
> 
> PE1-AS1#ping vr CustomerA 172.16.1.2    <<<<<< remote PE to remote CE
> 
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 172.16.1.2, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max = 4/17/36 ms
> =============================================================================================
> 
> CEA-1#ping ip
> Target IP address: 170.4.2.0
> Source address or interface: 170.6.2.0
> Sending 5, 100-byte ICMP Echos to 170.4.2.0, timeout is 2 seconds:
> .....
> Success rate is 0 percent (0/5)
> =============================================================================================
> 
> even the trace doesnt give me a single hop :
> 
> CEA-1#trace ip
> 
> Target IP address: 170.4.2.0
> Source address: 170.6.2.0
> Tracing the route to 170.4.2.0
> 
>   1  *  *  *
> =============================================================================================
> 
> after many days of serach, i got stuck!
> 
> any suggestions?
> 
> 
> 
> Ahmed Abdelazim
> 
> CCNA-CCIP
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