From: Annu (annu_roopa@xxxxxxxxx)
Date: Thu Jan 03 2002 - 09:12:10 GMT-3
Bhisham,
I think u need to configure Area 2 as NSSA. Area 2
will then get the type 7 LSA bcoz of ASBR an then the
ABR will convert it to type 5 and send it to other
areas.
Stub and TS areas will get default of course.But area
2 which is NSSA will not get any external routes from
other areas (Stub to other areas) and will only get
this external route.Hope this link helps.
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/ip_c/ip
cprt2/1cdospf.htm#xtocid2512710
http://www.cisco.com/warp/public/104/8.html
hope this helps.Let us know.
Good luck,
Annu
--- Bhisham Bajaj <bhishambajaj@yahoo.com> wrote:
> I have three are 0, 1,2
>
>
> 1----------0----------2
>
> my are I is a stub are so I will not get las 5 in it
> but instead I will get a default route from the abr
> to
> reach the external routes
> my are 1 canot have a ASBR in it and cannot have
> virtual link
>
> my are 2 has an ASBR in it and is injecting the
> external routes ( lsa 5 ) int the back bone
>
> know is it that when I wont the area 1 to have a
> asbr
> int it but not get the routes thar are injected int
> area 0 by the asbr of area 2 I will have to
> configure
> are 1 as a NSSA
>
> thank u
> Reg
> Bhisham
>
> --- Peter van Oene <pvo@usermail.com> wrote:
> > OSPF networks have a few major scaling problems.
> The
> > main one is that type
> > 5 LSA (external) flood throughout the entire OSPF
> > domain. What this means
> > is that no matter how many areas you create, your
> > type 5's still require
> > processing by all your routers. In order to
> > constrain this, you can
> > create stub areas which restrict the flow of type
> > 5's and type 4's such
> > that the routers in the area need not to worry
> about
> > processing type
> > 5's. However, what happens when you want to push
> > some statics into an
> > area that you have designated at stub?
> Essentially,
> > you've decided that
> > there is no value in flooding a mess of external
> > information into the area,
> > however, you'd still need to get these few
> externals
> > into OSPF in that
> > area. Without NSSA you'd have to make the area a
> > normal stub area and
> > you'd be able to get your few new type 5's in but
> > would also get all of the
> > type 5's from the rest of the OSPF domain.
> However,
> > by making it an NSSA,
> > you have the ability to inject these few new
> > externals as type 7's (which
> > look like 5's, just with another name) without
> > having to absorb all of the
> > type 5's you didn't want in the first place. These
> > 7's get translated into
> > the rest of the normal OSPF domain at Type 5's all
> > is good.
> >
> > NSSA is a very common option in OSPF networks and
> is
> > definitely worth some
> > study time.
> >
> > Hope this helps.
> >
> > Pete
> >
> >
> >
> > At 07:30 PM 1/2/2002 -0800, Bhisham Bajaj wrote:
> > >Hi
> > >
> > >I am trying to understand the concept of NSSA
> area
> > >
> > >I tried to read a few doc on it but did not help
> > >
> > >Can some one explain me this or guide me to some
> > good
> > >link for it
> > >
> > >Thank u
> > >bhisham
> > >
> > >
> >
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