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Configuring OSPF 431
Specifying the
Retransmitting Interval
The router waits for confirmation from the neighbor to whom it has sent an LSA. If
the router does not receive the neighbor's confirmation after a specified interval,
the retransmitting interval, it resends the LSA. You can set the time interval for
re-transmitting an LSA.
Perform the following configurations in interface view.
Table 496 Specify Retransmitting Interval
By default, the retransmitting interval is 5 seconds.
The retransmitting interval must be twice of the period when a message is
transmitted between two routers.
The interval for retransmitting an LSA between adjacent routers must not be so
small as to cause unnecessary retransmission.
Specifying the
Transmit-delay
The LSA ages in the link status database (LSDB) of the local router (1 is added per
second), but not during the process of network transmission. Therefore, it is
necessary to add the aging time before the transmission. Set and adjust this
parameter according to the actual situation in the low-speed network.
Perform the following configurations in interface view.
Table 497 Specify Transmit-delay
By default, the time for transmit-delay is 1 second.
Configuring a Stubby
Area and a Totally
Stubby Area
Usually, OSPF has 5 kinds of LSA packets, as follows:
■ Router-LSA: Generated by each router and transmitted to the whole area,
describing link status and cost of the router.
■ Network-LSA: Generated by the DR and transmitted to the whole area,
describing the link status of local network segment.
■ Net-Summary-LSA: Generated by the ABR and transmitted to relevant areas,
describing routing of certain network segment of the area.
■ Asbr-Summary-LSA: Generated by the ABR and transmitted to relevant area,
describing routing to ASBR.
■ AS-External-LSA: Generated by the ASBR and transmitted to the whole AS
(excluding the Stub area), describing routing to AS external.
A “stub area” is the area that does not advertise the received external LSA, inside
which the scale of the routing table and the quantity of the transmitted routing
Operation Command
Configure the interval of LSA
retransmission for the neighboring routers
ospf timer retransmit seconds
Return to the default value of
re-transmitting interval
undo ospf timer retransmit
Operation Command
Set the delay time of LSA tramsmission ospf trans-delay seconds
Return the default value of transmit-delay undo ospf trans-delay