HPE FlexNetwork HSR6800 Configuration Manual page 274

Protocol: BGP
Preference: 0
NextHop: 3.0.1.1
BkNextHop: 0.0.0.0
RelyNextHop: 3.0.2.1
Tunnel ID: 0x0
State: Active Adv
Tag: 0
Destination: 1.1.1.0/24
Protocol: BGP
Preference: 0
NextHop: 2.0.1.1
BkNextHop: 0.0.0.0
RelyNextHop: 2.0.2.1
Tunnel ID: 0x0
State: Invalid Adv
Tag: 0
The output shows that Router C has two routes to reach network 1.1.1.0/24: Router
C<—>Router B<—>Router A, which is the currently active route; Router C<—>Router
D<—>Router A, which is the backup route.
# Enable BFD debugging on Router C.
<RouterC> debugging bfd scm
<RouterC> debugging bfd event
<RouterC> debugging bgp bfd
<RouterC> terminal monitor
<RouterC> terminal debugging
# The following debugging information shows that: when the link between Router A and Router
B fails, Router C can quickly detect the link failure.
%Nov 5 11:42:24:172 2009 RouterC BFD/5/BFD_CHANGE_FSM:
Sess[3.0.2.2/3.0.1.1,13/17,GE2/1/1,Ctrl], Sta: UP->DOWN, Diag: 1
%Nov 5 11:42:24:172 2009 RouterC BGP/5/BGP_STATE_CHANGED: 3.0.1.1 state is changed
from ESTABLISHED to IDLE.
*Nov 5 11:42:24:187 2009 RouterC RM/6/RMDEBUG: BGP_BFD: Recv BFD DOWN msg, Src IP
3.0.2.2, Dst IP 3.0.1.1, Instance ID 0.
*Nov 5 11:42:24:187 2009 RouterC RM/6/RMDEBUG: BGP_BFD: Reset BGP session 3.0.1.1
for BFD session down.
*Nov 5 11:42:24:187 2009 RouterC RM/6/RMDEBUG: BGP_BFD: Send DELETE msg to BFD,
Connection type DIRECT, Src IP 3.0.2.2, Dst IP 3.0.1.1, Instance ID 0.
# Display route 1.1.1.0/24 on Router C, and you can see that Router A and Router C
communicate through Router D.
<RouterC> display ip routing-table 1.1.1.0 24 verbose
Routing Table : Public
Summary Count : 1
Destination: 1.1.1.0/24
Protocol: BGP
Preference: 0
NextHop: 2.0.1.1
Process ID: 0
Cost: 50
Interface: GigabitEthernet2/1/1
BkInterface:
Neighbor : 3.0.1.1
Label: NULL
Age: 00h08m54s
Process ID: 0
Cost: 100
Interface: GigabitEthernet2/1/2
BkInterface:
Neighbor : 2.0.1.1
Label: NULL
Age: 00h08m54s
Process ID: 0
Cost: 100
Interface: GigabitEthernet2/1/2
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