Two Cisco 7606
routers and two Huawei NE20-Ss are connected in a square-shaped topology. The
two Cisco devices and two Huawei devices both work in backup mode. OSPF runs
between these devices. If the master Huawei device or master Cisco device
becomes faulty, services are interrupted for about 40 seconds.
The network topology is as follows:
1. Check that
the device configuration is correct.
2. Ping the master 7606 router from the core switch. It is found
packet loss occurs for about 40 seconds. Ping the master NE20E from the core
switch. Packet loss occurs also for about 40 seconds.
3. Disconnect the link with the master NE20E.. Check the OSPF
routing table. It is found that the next hop is instantly switched to the slave
4. Confirm that OSPF convergence works properly on NE20Es.
5. Perform the same operations on 7606 routers. It is found that
OSPF convergence also works properly on 7606 routers.
6. Disconnect the link connecting two 7606 routers and the link
connecting two NE20Es. Then, ping these devices from the core switch. It is
found that only four packets are lost, and services are switched quickly.
that an encryption device exists on the links between 7606 routers and NE20Es.
When the link on one end is disconnected, the interface of the master device on
the link on the other end is still up. Therefore, OSPF convergence succeeds
after Hello Dead (40s) times out.
Other devices exist between the links connecting the master devices. When
the link on one end is disconnected, the interface of the master device on the
link on the other end is still up. Therefore, OSPF convergence succeeds after
Hello Dead (40s) times out.
Configure BFD and OSPF association with BFD on devices so that routers on
both ends of a link can be quickly notified of link failures. This triggers fast