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

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Verifying the configuration.
# On Host B, specify Router C as the default gateway. Ping Host A from Host B. The ping operation
succeeds. View tunnel entries on Router A:
[RouterA] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
192.168.1.0 255.255.255.0 11.1.1.3 2
# On Host B, specify Router B as the default gateway. Ping Host A from Host B. The ping operation
succeeds. View tunnel entries on Router A:
[RouterA] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
192.168.1.0 255.255.255.0 11.1.1.3 2
192.168.1.0 255.255.255.0 11.1.1.2 1
The output shows that Router A has two tunnel entries to the branch network and prefers the tunnel entry
with a smaller GRE key value. Packets are forwarded to hosts on the branch network through Router B
first.
# On Router B, shut down the tunnel interface Tunnel 0 to cut off the tunnel link between Router A and
Router B.
[RouterB] interface tunnel 0
[RouterB-Tunnel0] shutdown
# On Host B, specify Router C as the default gateway. After the tunnel entry corresponding to Router B
ages out, ping Host A from Host B. The ping operation succeeds. View tunnel entries on Router A:
[RouterA] display gre p2mp tunnel-table interface tunnel 0
Dest Addr Mask Tunnel Dest Addr Gre Key
192.168.1.0 24 11.1.1.3 2
The output shows that after the link between Router A and Router B fails, Router A has only the tunnel
entry that uses Router C to forward packets to the branch network.