From: Ibrahim kabir (kebramccie@live.com)
Date: Tue May 13 2008 - 03:57:30 ART
Uyota,
A stub area does not allow external routes. Bt allows Inter-area routes.
(Area 1 stub) It should be noted that the backbone area cannot be configured
as a stub area. In Other words a stub area does not allow AS External LSA
(type 5) into it.
A totally stubby area denies external routes, and Inter area. (Area 1 stub
no-summary).
A NSSA just like a stub prevents AS External LSA's from flooding an area. But
in situations where an ASBR is located in an area. The area becomes ineligible
to become either a stub or a totally stubby area. The area could be configured
as an NSSA. The ABR of that area will be responsible for type 7 LSA
translation to type 5 as Routes (External) enter from the NSSA area into the
backbone. (area 1 nssa)
A NSSA totally stubby area (area 1 nssa no-summary) does the NSSA type of wat
a totally stubby Area does. It does not Allow External LSA's and also
inter-area routes.
To answer your question you configure stub wen u have no ASBR is present in an
area and NSSA to do exactly wat a stub does wen an ASBR is present. (A NSSA
does nt accept External type 5 bt sends as Type 7 )
Kabir K IbrahimB.sc CCNA CCNP CCDP CCNP MCP
+2348036477283
> Date: Tue, 13 May 2008 01:19:20 -0400> From: spycharlies@gmail.com> To:
ccielab@groupstudy.com> Subject: ospf stub & NSSA> > Hi guys,> > > > I am not
100% comfortable distinguishing btw. when to use nssa or stub> > > > Assuming
R1 connection to the rest of the ospf domain is through R3. Since> R1 does not
need specific routing information to the rest of the network, it> just needs
to receive only a default route.> > > > ***> > These two solutions seems to be
doing the same thing for me> > ***> > *Solution 1*> > > > R3#> > router ospf
1> > area 5 nssa no-summary> > > > R1#> > area 5 nssa.> > > > > > *Sol.2*> > >
> R3#> > area 5 stub no-summary> > > > R1#> > area 5 stub> > > > ***> > My
question is when can you categorically use nssa over stub, or vice-versa?> > >
> Thanks> > > > Uyota> > >
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