3Com 10014299 manual Configuring a Stubby Area and a Totally, Specify Retransmitting Interval

Configuring OSPF 431

Specifying the The router waits for confirmation from the neighbor to whom it has sent an LSA. If Retransmitting Interval 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

Operation	Command
Configure the interval of LSA	ospf	timer retransmit seconds
retransmission for the neighboring routers
Return to the default value of	undo	ospf timer retransmit
re-transmitting 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 The LSA ages in the link status database (LSDB) of the local router (1 is added per Transmit-delaysecond), 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.

Configuring a Stubby

Area and a Totally

Stubby Area

Table 497 Specify Transmit-delay

Operation	Command
Set the delay time of LSA tramsmission	ospf	trans-delay seconds
Return the default value of transmit-delay	undo	ospf trans-delay

By default, the time for transmit-delay is 1 second.

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