Ed,
You have a point... I answered this too thoughtlessly.
Internal Routers(2) Area 1 ABR Area0 ABR Area 2 Internal Routers(2)
ABR Area 1
The basic question is if there is an ABR that has interfaces in area 1 and
2, will it send the updates to area 0 once area 0 loses its interface to
area 1?
If the ABR of area 2 has an interface in area 1 and area 0, then area 0 will
learn about area 1 routes via this ABR even if the ABR of area 0 loses its
link to area 1. (ABR is connecting 3 areas)
If the ABR of area 2 has an interface in area 1 but not in area 0 (assuming
area 2 has another ABR with an interface in area 2 and in area 0, then area
0 will not learn about the route in area 1. You can implement virtual links
to work around this.
I violated OSPF's most fundamental principle with my quick answer: all
areas must touch area 0.
Sorry for any confusion, and thanks Ed for calling me on it!
Charles
>From: "Edward Moss" <[EMAIL PROTECTED]>
>To: "\"Cthulu, CCIE Candidate\"" <[EMAIL PROTECTED]>
>Subject: Re: OSPF AREA Confusion
>Date: Sun, 24 Sep 2000 19:05:36 -0500
>
>I dont think the statement is quite true....
>If the link between area 0 and 1 goes down,
>There is still a link between area 1 and 2.
>
>But area 0 will have no knowledge of area 1 any more since the link is
down.
>A virtual link would be needed to connect area 1 and 0 via area 2.
>
>Ed
>
>
""Cthulu, CCIE Candidate"" <[EMAIL PROTECTED]> wrote in message
8qid12$2qi$[EMAIL PROTECTED]">news:8qid12$2qi$[EMAIL PROTECTED]...
>
>
> If I read your message correctly, you have:
>
> Internal Routers(2) Area 1 ABR Area0 ABR Area 2 Internal
Routers(2)
>
> A router in area 1 now has a link to area 2 (in other words, it has an
> interface in area 1 and 2).
>
> What you want will happen automatically. Remember that OSPF enabled
routers
> have a complete picture of the network with themselves as the chewy creamy
> center. If a link goes down, that Dij algorithm gets recalculated, and
> voila, a new picture of the network, with the failed link kicked aside.
>
> Did I understand your question correctly? If not, let me know.
>
> HTH,
>
> Charles
>
>
>
> "vasu" <[EMAIL PROTECTED]> wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Greetings,
> > Guys
> > I am little bit confused with OSPF Configuration. Please help me
> > out.
> > 1. Just imagine that i need 3 area's to be configured including area
> > 0.
> > 2. Assume that i have 2 routers in area 0
> > and Area 1 and Area 2 are having 2 routers each.
> > 3. Just imagine one of the router which was in area 1 gets new
> > link and that to
> > be connceted to area 2 for fault tolerance. That means i want
> > the serial link which was only in area 1 to be functional by default
> > and suppose if the link which is configured in area 1 fails the router
> > should take area 2 link.
> > 4. All these areas are interconnected via serial links.
> >
> > Hope this is sufficient to get the best solution
> > This is the problem what i am facing. Help me out.
> >
> > Atul
> >
> >
> >
> > **NOTE: New CCNA/CCDA List has been formed. For more information go to
> > http://www.groupstudy.com/list/Associates.html
> > _________________________________
> > UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> > FAQ, list archives, and subscription info: http://www.groupstudy.com
> > Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
> >
>
>
> **NOTE: New CCNA/CCDA List has been formed. For more information go to
> http://www.groupstudy.com/list/Associates.html
> _________________________________
> UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
> FAQ, list archives, and subscription info: http://www.groupstudy.com
> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
>
**NOTE: New CCNA/CCDA List has been formed. For more information go to
http://www.groupstudy.com/list/Associates.html
_________________________________
UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html
FAQ, list archives, and subscription info: http://www.groupstudy.com
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
