if router's serial line(ex,45Mbps) have a problem,
we conduct a loopback test for the interface.
before this test,
I delete the ospf config about that interface subnet to prevent data transfer through it.
router ospf 10
network 10.10.10.1 0.0.0.0 area 0
ip addr 10.10.10.1 255.255.255.0
when I conduct a loopback-test for int se1/0
i delete the network for int se1/0 in ospf
router ospf 10
no network 10.10.10.1 0.0.0.0 area 0
but i wonder whether above deleting is need?
when serial interface looped back for testing,
ospf doesn't any LSA update?
for example, LSA update for the interface network.
if it does,
i don't need deleting operation.
anyone knows about this ospf issue?
OSPF protocol can deal with the loopback test:
the router will simply complain about receiving its own OSPF hello packets back and this can produce some syslog messages but no real issues.
OSPF hello packet contain the OSPF router-id of the sender so the device can safely detect the loop at the OSPF level.
I wouldn't remove the network ... area command actually only traffic for the ip subnet on the serial link could be sent out it during the loopback test if the interface state ip up/up (looped)
No OSPF adjacency can be built on the looped link so no other IP subnets can use it as outgoing interface.
The previous OSPF adjacency fails in 40 seconds (dead interval) and the SPF is recomputed for all destinations taking in account this event.
It can be a good practice to remove the network ... area for the reasons above:
elimination of warning messages in log
reduction of time to detect that no neighbor is available.
But it is not stricly necessary.
Hope to help