Frame Relay
jwills
Member Posts: 44 ■■□□□□□□□□
in CCNA & CCENT
If you administratively shut down a physical serial interface or even a subinterface between 2 routers with ospf on frame relay, will they still be listed as neighbors with a show command. My first thoughts would be that they would be neighbors if the subinterface was shut down, but would not be neighbors if the physical interface was shut down. My boson simulator has them being listed as neighbors in either case.
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Comments
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networker050184 Mod Posts: 11,962 ModFirst think how OSPF neighbors are formed and maintained. They use the hello message to maintain the neighbor relationship. So if you shutdown the link between two routers and no hello messages come across do you think the neighbor will stay up?An expert is a man who has made all the mistakes which can be made.
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jwills Member Posts: 44 ■■□□□□□□□□Thats exactly what i was thinking when it came to the physical interface. Is it the same for the subinterface though? My first thought would be that the hellos are only communicated between the physical interfaces of the 2 routers. So if the subinterface is down, the router would still be receiving hellos. Correct me if i'm wrong.
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networker050184 Mod Posts: 11,962 ModThe hellos are sent out of the interface with the IP address specified in the network command. So if you have the IP on the subinterface then shutting that down will kill the neighbor.
Also keep the hello/dead intervals in mind. For an NBMA interface the default is 30/120 so the neighbors will stay adjacent for some time if hellos are stopped.An expert is a man who has made all the mistakes which can be made.