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just chitchat...how can it possible to get an older LSA
the_return_of_the_Ring
Member Posts: 119
in CCNP
I'm reading ospf in a single area...correct me if i'm wrong.
according to the design, in a multiaccess network, all routers build the adjacency with the elected DR and BDR. Then, I suppose every other routers get LSA from DR/BDR. But the cisco press book uses some lines to discuss about comparing the old LSA or new LSA. I don't get this. If LSA is from DR, it must be sequenceed; how can it possible to be old?
When I'm reading new stuff, I put myself to the thought of the designer. Just like in CCNA preparation, I don't get why they made the design like that. Here's another one.
On designing the states of building adjacency between routers, why they created LSR? wouldn't it be convenient that the DR gives all information in DDP? I mean if DDP gets very large it's fine, at least there's no additional request for "info about this" or "info about that". What's the trick behind all this?
according to the design, in a multiaccess network, all routers build the adjacency with the elected DR and BDR. Then, I suppose every other routers get LSA from DR/BDR. But the cisco press book uses some lines to discuss about comparing the old LSA or new LSA. I don't get this. If LSA is from DR, it must be sequenceed; how can it possible to be old?
When I'm reading new stuff, I put myself to the thought of the designer. Just like in CCNA preparation, I don't get why they made the design like that. Here's another one.
On designing the states of building adjacency between routers, why they created LSR? wouldn't it be convenient that the DR gives all information in DDP? I mean if DDP gets very large it's fine, at least there's no additional request for "info about this" or "info about that". What's the trick behind all this?
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OptionsHumper
Member Posts: 647
My very "uneducated" understanding of the link-state routing protocols is that it could be old due to being shutdown or disconnected (NOTE: I do not know how this would be affected with a DR and BDR) When a router sends out an LSA and the receiving router realizes that it is old, it would send a new LSA back to the router and get it synched into place.
I may be entirely wrong seeing as I am just reading the "Dynamic Routing Protocol" chapter of Doyles book.Now working full time!