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Pinging the Remote PE and CE Routers from the Local CE Router

From the local CE router, you can ping the VPN interfaces on the remote PE and CE routers, which are point-to-point interfaces. Troubleshooting Layer 3 VPNs Using ping and traceroute shows the topology referenced in the following examples:

Pinging Router CE2 from Router CE1

Ping Router CE2 (VPN5) from Router CE1 (VPN4):


user@vpn4> ping 192.168.193.5 local 10.255.10.4 count 3
PING 192.168.193.5 (192.168.193.5): 56 data bytes
64 bytes from 192.168.193.5: icmp_seq=0 ttl=253 time=1.040 ms
64 bytes from 192.168.193.5: icmp_seq=1 ttl=253 time=0.891 ms
64 bytes from 192.168.193.5: icmp_seq=2 ttl=253 time=0.944 ms
--- 192.168.193.5 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.891/0.958/1.040/0.062 ms

Using traceroute from Router CE1 to Router CE2

To determine the path from Router CE1’s loopback interface to Router CE2’s directly connected interface, use the traceroute command:


user@vpn4> traceroute 192.168.193.5 source 10.255.10.4
traceroute to 192.168.193.5 (192.168.193.5) from 10.255.10.4, 30 hops max, 40 byte packets
 1  vpn1-fe-110.isp-core.net (192.168.192.1)  0.669 ms  0.508 ms  0.457 ms
 2  vpn2-t3-001.isp-core.net (192.168.192.110)  0.851 ms  0.769 ms  0.750 ms
     MPLS Label=100000 CoS=0 TTL=1 S=1
 3  vpn5-t3-003.isp-core.net (192.168.193.5)  0.829 ms  0.838 ms  0.731 ms

Pinging Router PE2 from Router CE1

Ping Router PE2 (VPN2) from Router CE1 (VPN4). In this case, packets that originate at Router CE1 go to Router PE2, then to Router CE2, and back to Router PE2 before Router PE2 can respond to Internet Control Message Protocol (ICMP) requests. You can verify this by using the traceroute command.


user@vpn4> ping 192.168.193.2 local 10.255.10.4 count 3
PING 192.168.193.2 (192.168.193.2): 56 data bytes
64 bytes from 192.168.193.2: icmp_seq=0 ttl=254 time=1.080 ms
64 bytes from 192.168.193.2: icmp_seq=1 ttl=254 time=0.967 ms
64 bytes from 192.168.193.2: icmp_seq=2 ttl=254 time=0.983 ms
--- 192.168.193.2 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.967/1.010/1.080/0.050 ms

Using traceroute from Router CE1 to Router PE2

To determine the path from Router CE1 to Router PE2, use the traceroute command:


user@vpn4> traceroute 192.168.193.2 source 10.255.10.4
traceroute to 192.168.193.2 (192.168.193.2) from 10.255.10.4, 30 hops max, 40 byte packets
 1  vpn1-fe-110.isp-core.net (192.168.192.1)  0.690 ms  0.490 ms  0.458 ms
 2  vpn2-t3-003.isp-core.net (192.168.193.2)  0.846 ms  0.768 ms  0.749 ms
     MPLS Label=100000 CoS=0 TTL=1 S=1
 3  vpn5-t3-003.isp-core.net (192.168.193.5)  0.643 ms  0.703 ms  0.600 ms
 4  vpn-08-t3-003.isp-core.net (192.168.193.2)  0.810 ms  0.739 ms  0.729 ms

Pinging a CE Router from a Multiaccess Interface

You cannot ping one CE router from the other if the VPN interface is a multiaccess interface, such as the fe-1/1/2.0 interface on Router CE1. To ping Router CE1 from Router CE2, you must either include the vrf-table-label statement at the [edit routing-instances routing-instance-name] hierarchy level on Router PE1 or configure a static route on Router PE1 to the VPN interface of Router CE1. If you include the vrf-table-label statement to ping a router, you cannot configure a static route.

If you configure a static route on Router PE1 to the VPN interface of Router CE1, its next hop must point to Router CE1 (at the [edit routing-instance routing-instance-name] hierarchy level), and this route must be announced from Router PE1 to Router PE2 as shown in the following configuration:

[edit]routing-instances {direct-multipoint {instance-type vrf;interface fe-1/1/0.0;route-distinguisher 69:1;vrf-import direct-import;vrf-export direct-export;routing-options {static {route 192.168.192.4/32 next-hop 192.168.192.4;}}protocols {bgp {group to-vpn4 {peer-as 1;neighbor 192.168.192.4;}}}}policy-options {policy-statement direct-export {term a {from protocol bgp;then {community add direct-comm;accept;}}term b {from {protocol static;route-filter 192.168.192.4/32 exact;}then {community add direct-comm;accept;}}term d {then reject;}}}}

Now you can ping Router CE1 from Router CE2:


user@vpn5> ping 192.168.192.4 local 10.255.10.5 count 3
PING 192.168.192.4 (192.168.192.4): 56 data bytes
64 bytes from 192.168.192.4: icmp_seq=0 ttl=253 time=1.092 ms
64 bytes from 192.168.192.4: icmp_seq=1 ttl=253 time=1.019 ms
64 bytes from 192.168.192.4: icmp_seq=2 ttl=253 time=1.031 ms
--- 192.168.192.4 ping statistics ---
3 packets transmitted, 3 packets received, 0% packet loss
round-trip min/avg/max/stddev = 1.019/1.047/1.092/0.032 ms

To determine the path between these two interfaces, use the traceroute command:


user@vpn5> traceroute 192.168.192.4 source 10.255.10.5
traceroute to 192.168.192.4 (192.168.192.4) from 10.255.10.5, 30 hops max, 40 byte packets
 1  vpn-08-t3003.isp-core.net (192.168.193.2)  0.678 ms  0.549 ms  0.494 ms
 2  vpn1-so-100.isp-core.net (192.168.192.100)  0.873 ms  0.847 ms  0.844 ms
     MPLS Label=100021 CoS=0 TTL=1 S=1
 3  vpn4-fe-112.isp-core.net (192.168.192.4)  0.825 ms  0.743 ms  0.764 ms

Published: 2010-04-27

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