From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Tue Jul 23 2002 - 22:11:20 GMT-3
> Also, if you configure the "default-information-originate" on an ASBR
> you will need to configure a default route 0.0.0.0/0. This rule does
> not apply to an ABR. But now I am going to head to the lab late tonight
> because I don't know how the "default-information-originate" works if
> you configure it on an ABR/ASBR :); do you still have to configure a
> default route 0.0.0.0/0 on a router acting as an ABR/ASBR? Or do you
> configure it only when it is an ASBR? HHMMMM? If anyone can answer this
> one for me I'd surely appreciate it!
* Fundamental rule is that "if a router originates/advertises a default
route" it becomes an ASBR.
* Default information originate, if used on a router & if it has a default
route, it becomes an ASBR.(so if you configure on a ABR, it becomes an ASBR)
* If it doesnt have a default route, you can either use the "always" keyword
(which will trigger the generation of default route, regardless of the
possession of one), or create/point a default route. (in this case as well,
it becomes an ASBR)
* In the above scenario, you can use a "route map" for conditionally
advertising a default route. This route map will check for the presence of a
particular prefix and only generate the default if the prefix exists in the
routing table.
rgds
Nick
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Anthony Pace
> Sent: Tuesday, July 23, 2002 2:57 PM
> To: ccie candidate; Louis Young; ccielab@groupstudy.com; Khurram Khani
> Subject: Re: Any tips when doing OSPF NSSA stuff?
>
> Is this correct: If you had an ASBR which was an ABR and used NSSA with
> "no-redistribute" you would stop the LSA-7 routes from being pushed
> into downstraem routers of the NSSA but the LSA-7 routes would go into
> Area-0 and change into LSA-5 and the NSSA could still get the "LSA-3
> 0.0.0.0" via this ABR if the "no-summary" was used?
>
> OR are you saying that "no-redistribution" simply keeps the LSA-7
> routes from going into area 0, thereby isolating them to the NSSA? (in
> which case I understood it backwards)
>
> Anthony Pace
>
>
> On Mon, 22 Jul 2002 13:00:50 -0700, "ccie candidate" <ccie1@lycos.com>
> said:
> > ok ;
> > the NSSA is similar to stub area , where only LSA3 (inter-area ) can
> > propagate inside the area , No LSA4 $ 5 is allowed.
> > teh diffrenece is that when you have another routing protocol
> > redistributing into the ospf domain ( something like rip or redist
> > static ) and the redistributio point is one of the down stream routers
> > of the NSSA , then an LSA7 will also propagate inside the area , when
> > it reaches the ABR (which is propably connected to area 0) it gets
> > converted into LSA5 and propagate inside the domain .
> >
> > here are some tips .
> > 1-NSSA is does not propagate default route back to the down steam
> > routes unless you add NO-Summary option
> > area 30 nssa no-summary
> >
> > 2-when you have the ABR is also ASBR , you have another two options
> for
> > that command
> >
> > no-redistribution , will not allow the router to convert lsa7 to lsa5
> >
> > default-orginate , will propagate a default when the no-summary is not
> > used .
> >
> > hope this helps
> >
> >
> >
> > --
> >
> > On Mon, 22 Jul 2002 11:28:21
> > Khurram Khani wrote:
> > >Look for scenario when NSSA ABR is also ASBR. It generates both Type
> 5 and
> > >Type 7 LSAs.
> > >
> > >Thanks
> > >Khurram
> > >----- Original Message -----
> > >From: "Louis Young" <tonyblair@etang.com>
> > >To: <ccielab@groupstudy.com>
> > >Sent: Monday, July 22, 2002 2:25 AM
> > >Subject: Any tips when doing OSPF NSSA stuff?
> > >
> > >
> > >> Hi all ,I was bewildered by some senarios about OSPF NSSA
> stuff,anyone can
> > >offer some general tips?
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