357
Neighbor : 3000::1 ProcessID : 0
Interface : Vlan-interface101 Protocol : BGP4+
State : Active Adv Cost : 50
Tunnel ID : 0x0 Label : NULL
Age : 4538sec
Destination : 1200:: PrefixLength : 64
NextHop : 2000::1 Preference : 255
RelayNextHop : 2001::2 Tag : 0H
Neighbor : 2000::1 ProcessID : 0
Interface : Vlan-interface201 Protocol : BGP4+
State : Invalid Adv Cost : 100
Tunnel ID : 0x0 Label : NULL
Age : 4515sec
The output shows that Switch A and Switch C communicate through Switch B, and Switch C has
two routes to reach network 1200::0/64: Switch C<—>Switch B<—>Switch A, which is the
currently active route; Switch C<—>Switch D<—>Switch A, which is the backup route.
When the link Switch C<—>Switch B<—>Switch A fails, Switch C can quickly detect the failure on
Switch B.
# Display route 1200::0/64 on Switch C.
<SwitchC> display ipv6 routing-table 1200::0 64 verbose
Routing Table :
Summary Count : 1
Destination : 1200:: PrefixLength : 64
NextHop : 2000::1 Preference : 255
RelayNextHop : 2001::2 Tag : 0H
Neighbor : 2000::1 ProcessID : 0
Interface : Vlan-interface201 Protocol : BGP4+
State : Active Adv Cost : 100
Tunnel ID : 0x0 Label : NULL
Age : 4635sec
The output shows that Switch A and Switch C communicate through Switch D, and Switch C has
one route to reach network 1200::0/64, that is, Switch C<—>Switch D<—>Switch A.
Troubleshooting IPv6 BGP configuration
IPv6 BGP peer relationship not established
Symptom
Display BGP peer information by using the
display bgp ipv6 peer
command. The state of the connection
to the peer cannot become established.
Analysis
To become IPv6 BGP peers, any two routers must establish a TCP session using port 179 and exchange
open messages successfully.