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OSPF - area not contiguous

Answered Question
Jun 2nd, 2003
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I’d like to know if it’s possible to have two areas (5, for instance) connected

to the same area 0 backbone, but not connected to each other (two isolated area 5)

It can cause some instability or problem to my system?

thanks.

Correct Answer by bbranch about 14 years 2 months ago

As long as each Area 5's IP addressing is unique it does not matter if the two Area 5's are connected or not, each Area 5 will inject it's own Type 3 LSA's into Area 0. If, however, you are doing summaristion on the borders make sure your summary addresses do not overlap, if they do then you will have conectivity problems.


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rais Mon, 06/02/2003 - 12:00
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I dont thnk any thing will happen. If you had two ABRs for area 5, both ABRs will still exchange prefixes with the backbone and backbone wont even know what happened to area 5.


Are you seeing any problems?


Thanks.

ruwhite Mon, 06/02/2003 - 12:51
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It should work fine--there's nothing in the type 3 originated into area 0 that tells the other routers in the network what area the type 3 came from, just which abr to send the packets to for the desintation advertised.


Russ

Correct Answer
bbranch Tue, 06/03/2003 - 00:14
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As long as each Area 5's IP addressing is unique it does not matter if the two Area 5's are connected or not, each Area 5 will inject it's own Type 3 LSA's into Area 0. If, however, you are doing summaristion on the borders make sure your summary addresses do not overlap, if they do then you will have conectivity problems.


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