OSPF area types

Answered Question
Jun 18th, 2009
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Hi,


What is the difference between these two commands "nssa no-summary" and "stub no-summary"?


Do both these commands acts as a totally stubby area and block all the LSA type 3,4 and 5 messages ?




Thanks

Prasad

Correct Answer by thotsaphon about 7 years 10 months ago

Prasad,

- Stub area does not allow Type5(No ASBR).

- NSSA area does not allow Type5 but allows type7(Created by ASBR).

- No-summary keyword means InterArea routes aren't allowed(Type3,4)


HTH,

Toshi

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Correct Answer
thotsaphon Thu, 06/18/2009 - 09:37
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Prasad,

- Stub area does not allow Type5(No ASBR).

- NSSA area does not allow Type5 but allows type7(Created by ASBR).

- No-summary keyword means InterArea routes aren't allowed(Type3,4)


HTH,

Toshi

Edison Ortiz Thu, 06/18/2009 - 09:43
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The main difference between the 2 is the function of the border router.


With a totally stub design, the border router participating in the area can't be the redistribution point of the network.


With a nssa totally stubby design, the border router participating in the area can be used as a redistribution point for external areas.


Both designs will inject a 0.0.0.0 LSA Type 3 into the area.


HTH,


__


Edison.

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