R3303-HP HSR6800 Routers Layer 3 - IP Services Configuration Guide

285
[RouterC-Tunnel1] quit
# Configure a static route to the headquarters network with the outgoing interface being Tunnel 1
and priority value being 10. This makes the priority of this route lower than that of the static route
of interface Tunnel 0, making sure that Router C prefers the tunnel between Router A and Router C
for packet forwarding.
[RouterC] ip route-static 192.168.11.0 255.255.255.0 tunnel 1 preference 10
If the link between Router A and Router C goes down, Router C will sense the failure and try to send
packets to Router B, initiating the establishment of the tunnel between Router B and Router C. Only
then can Router B learn the tunnel entry.
If Router A and Router C are directly connected, configuring a static route on Router C can make
sure that Router C senses the failure of the link between Router A and Router C. If the two are not
directly connected, you can use either of the following methods to achieve the effect:
{ Configure dynamic routing on Router A, Router B, and Router C.
{ On Router C, associate the static route with a track entry, so as to use the track entry to track the
status of the static route. For details about track entry, see High Availability Configuration
Guide.
Verifying the configuration.
# Ping Host A from Host C. The operation succeeds. View the tunnel entries on Router A and Router B.
[RouterA] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
192.168.12.0 255.255.255.0 11.1.1.3
[RouterB] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
The output shows that on Router A has a tunnel entry to the branch network. Packets to the branch
network are forwarded through Router A.
# On Router C, shut down interface Tunnel 0 to cut off the tunnel link between Router A and Router C.
[RouterC] interface tunnel 0
[RouterC-Tunnel0] shutdown
# After the tunnel entry aging time (20 seconds in this example) elapses, view the tunnel entry
information on Router A.
[RouterA] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
# Ping Host A from Host C. View tunnel entries on Router B:
[RouterB] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
192.168.12.0 255.255.255.0 11.1.1.3
Then, Host A can ping Host C.
The verification process indicates that:
• After the link between Router A and Router C went down, the tunnel entry aging timer started to
work.
• After the timer expired, the tunnel entry on Router A was removed.
• After Router C sent a packet to Router B, a tunnel entry to the branch network was generated on
Router B. Packets from the headquarters to the branch network are delivered by Router A to Router
B through the backup interface, and then Router B forwards these packets to the branch.