361
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 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.
# Enable BFD debugging on Switch C.
<SwitchC> debugging bfd scm
<SwitchC> debugging bfd event
<SwitchC> debugging bgp bfd
<SwitchC> terminal monitor
<SwitchC> terminal debugging
# The following debugging information shows that Switch C can quickly detect the failure on Switch B.
%Nov 5 11:42:24:172 2009 SwitchC BFD/5/BFD_CHANGE_FSM: Sess[3001::3/3000::1,
13/17,VLAN101,Ctrl], Sta: UP->DOWN, Diag: 1
%Nov 5 11:42:24:172 2009 SwitchC BGP/5/BGP_STATE_CHANGED: 3000::1 state is changed from
ESTABLISHED to IDLE.
*Nov 5 11:42:24:187 2009 SwitchC RM/6/RMDEBUG: BGP_BFD: Recv BFD DOWN msg, Src IP 3001::3,
Dst IP 3000::1, Instance ID 0.
*Nov 5 11:42:24:187 2009 SwitchC RM/6/RMDEBUG: BGP_BFD: Reset BGP session 3000::1 for
BFD session down.
*Nov 5 11:42:24:187 2009 SwitchC RM/6/RMDEBUG: BGP_BFD: Send DELETE msg to BFD, Connection
type DIRECT, Src IP 3001::3, Dst IP 3000::1, Instance ID 0.
# Display route 1200::0/64 on Switch C, and you can see that Switch A and Switch C communicate
through Switch D.
<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