Does route in OSPF have to be "adjacent"?

johnifanx98

For example, router A and B are neighbor but not adjacent. Then is it a possible a route going through from A to B?

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networker050184

What do you mean are neighbor but not adjacent?

johnifanx98

networker050184 wrote: »

What do you mean are neighbor but not adjacent?

This is OSPF. In a broadcast network, not every pair of routers are "adjacent".

altdrugz

Maybe you are confused with the status and specially with the Two-way status. In a multiaccess broadcast network such as Ethernet, routers others than DRs and BDRs may stay in Two-way state and still be able to send adjacencies. As far as 2 routers are able to become neighbors they are able to exchange LSAs. So what is needed is the requirements of their handshake (Values in the Hello's packets that must be identical to both ends)

networker050184

The DR serves the function of distributing LSAs. Once that is done the routers run SPF and forward traffic as seen fit whether that be through the DR or other routers on the segment.

altdrugz

Well I didnt state it correctly. From CCNA Guide of Aaron Balchunas "On a multi access network, OSPF routers will only form Full adjacencies with DRs and BDRs. Non-DRs and non BDRs will still form adjacencies but will reamain in a 2-way state. This is normal OSPF behavior"

xXErebuS

altdrugz wrote: »

Well I didnt state it correctly. From CCNA Guide of Aaron Balchunas "On a multi access network, OSPF routers will only form Full adjacencies with DRs and BDRs. Non-DRs and non BDRs will still form adjacencies but will reamain in a 2-way state. This is normal OSPF behavior"

Still on par with what networker050184 said; the DR / BDR has "adjacencies" with every OSPF router even if they are not directly connected neighbors; the others have no reason to know about every OSPF router since they can get their LSA information about them from the DR / BDR so they form two way adjacencies with directly connected neighbors.