3Com Switch 8800 Configuration Guide
Chapter 37 BGP/MPLS VPN Configuration
37-90
[PE2-bgp] quit
Configure multi-role host feature.
Configure a default route pointing to PE1 on CE2.
[CE2] ip route-static 0.0.0.0 0.0.0.0 20.1.1.2
If routing protocol is used between CE2 and PE1, to avoid routing loop, disable PE1
from advertising any route to CE2. In this example, no routing protocol is used between
PE1 and CE2; so, a static route for PC2 is directly configured on PE1 (you can also
adopt other similar configuration here).
[PE1] ip route-static vpn-instance vpn2 172.16.0.0 16 20.1.1.1
Import the route of VPN1 to VPN2 using the VPN Target attribute.
[PE1] ip vpn-instance vpn2
[PE1-vpn-vpn2] vpn-target 100:1 import-extcommunity
37.5 Troubleshooting
I. Symptom 1
In central server topology networking mode, the local end switch (spoke PE) cannot
learn the routing information of the peer end switch (spoke PE).
Solution:
z
Check whether the BGP adjacent of spoke PE and hub PE is created correctly.
z
Check whether the routing attributes import/export relation of each VPN-instance
is correct.
z
Check from the hub PE that whether the routing information between two VPN
instances can be learnt by each other. if not, perform the following operation:
check if the EBGP protocol runs between hub PE and hub CE, check whether the
peer
peer
-
address
allow-as-loop
command is configured between PE and CE.
II. Symptom 2
PE at the local end can learn private network route of the PE at peer end, but two PEs
cannot intercommunicate with each other.
Solution:
z
Check whether the loopback interface configured on the PE has the address with
32-bit mask.
z
Check whether the tag of private network route is correct.
z
Check whether the LDP session is established using the
display
mpls
ldp
session
command.
z
Check whether the LSP tunnel is established using the
display
mpls
lsp
command.
