Troubleshooting guide

8-29
ATM and Layer 3 Switch Router Troubleshooting Guide
OL-1969-01
Chapter 8 Troubleshooting Tag and MPLS Switching Connections
Troubleshooting MPLS VPN
Border Gateway Protocol (BGP) is used between the PE routers and is necessary for inter-site
connectivity. In the following example, we use internal BGP (iBGP). You can also use external BGP
(eBGP) as an external routing protocol for Provider Edge-to-Customer Equipment route propagation.
You can use the following commands to troubleshoot BGP:
Step 3 Check the destination for a BGP address by entering the show ip bgp vpnv4 vrf command with the
VRF-name.
8540-PE2# show ip bgp vpnv4 vrf Green
BGP table version is 17, local router ID is 222.2.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 200:1 (default for vrf Green)
*>i111.0.2.100/30 222.2.1.1 0 100 0 ?
*> 111.0.2.116/30 0.0.0.0 0 32768 ?
8540-PE2#
Step 4 Check the destination for a BGP address by using the show ip bgp vpnv4 vrf command with the
VRF-name and IP-address.
8540-PE2# show ip bgp vpnv4 vrf Green 111.0.2.116
BGP routing table entry for 200:1:111.0.2.116/30, version 7
Paths: (1 available, best #1, table Green)
Advertised to non peer-group peers:
222.2.1.1
Local
0.0.0.0 from 0.0.0.0 (222.2.1.2)
Origin incomplete, metric 0, localpref 100, weight 32768, valid, sourced,t
Extended Community: RT:200:1
8540-PE2#
Step 5 If the routing protocol used on the customer side does not use BGP, you can use traditional show
commands, and apply them to the correct VRF.
Command Purpose
show ip bgp neighbors Shows detailed information on the BGP and TCP
connections to individual neighbors.
show ip bgp vpnv4 all Shows the VPN address information from the BGP table.
show ip bgp vpnv4 vrf
VRF-name
Shows network layer reachability information (NLRI)
associated with the named VRF.
show ip bgp vpnv4 vrf VRF
name [ip-address]
Shows NLRI associated with the named VRF and a specific
connection.