From: Bob Rech (brech@kc.rr.com)
Date: Mon Nov 18 2002 - 19:16:34 GMT-3
No question it is a bad design. virtual-areas in themselves should only be
used when there is no way to connect an area directly to the backbone, the
question was would it work and how. It actually does work, but should never
be considered in production networks.
Whether it is actually an un-supported configuration is another question. It
actually did work when I put it together.
----- Original Message -----
From: "Robert Massiache" <robert2140@hotmail.com>
To: <brech@kc.rr.com>; <bashir.sulaiman@netwise.co.uk>; <tasuka@mac.com>;
<ccielab@groupstudy.com>
Sent: Monday, November 18, 2002 4:08 PM
Subject: Re: OSPF Virtual link cross Multi area
> > > If a network topology like below:
> > >
> > > Area 0---Area 10---Area 20--Area 30
>
> This design is has to be re-structured. You can not have your area 30
trying
> to connect to area 0 using a virtual link or the virtual link can't have 2
> transit areas.
>
> You can't have an area (area 30) physically connected to another
'area'(area
> 20) which is already served by a virtual link. IMHO...It is considered to
be
> a bad design.
>
> Solutions:
> 1. Consider redesigning it and have area 30 physically connected to area
> 10(like area 20).
> 2. Have two different and discontinuous parts of area 0 and connect them
> through virtual links. Now you have the comfort of placing area 30 next to
> one of the discontinueous area 0.
> 3. Use GRE tunnel to connect the remote ends, now you will form adj. No
vir
> links needed. (beware it causes overhead)
>
> Ref:
> OSPF Design Guide by Sam Halabi
> http://www.cisco.com/warp/public/104/ospfdb7.html
> http://www.cisco.com/warp/public/104/2.html#8.0
>
> thanks
> Robert M
> CCIE #
>
>
>
>
>
>
> >From: "Bob Rech" <brech@kc.rr.com>
> >Reply-To: "Bob Rech" <brech@kc.rr.com>
> >To: "Bashir Sulaiman" <bashir.sulaiman@netwise.co.uk>, "'Tasuka
> >Amano Hsu'" <tasuka@mac.com>, "'ccielab Groupstudy'"
> ><ccielab@groupstudy.com>
> >Subject: Re: OSPF Virtual link cross Multi area
> >Date: Mon, 18 Nov 2002 11:46:14 -0600
> >
> >To make this work is ugly.
> >But having said that you can create
> >On the area 0 and area 10 routers
> >area 10 virtual-link <neighbor ospf ID>
> >On the area 10 and area 20 routers
> >area 20 virtual-link <neighbor ospf ID>
> >I did just put this together and the routes from area0 and area 30 do get
> >propagated all the way across. This is kind of like a vitual area through
> >another virtual area, I am not sure if this is a supported configuration,
> >but it appears work. All the virtual links come to FULL and all routers
> >show
> >an interface in area 0.
> >
> >----- Original Message -----
> >From: "Bashir Sulaiman" <bashir.sulaiman@netwise.co.uk>
> >To: "'Tasuka Amano Hsu'" <tasuka@mac.com>; "'ccielab Groupstudy'"
> ><ccielab@groupstudy.com>
> >Sent: Monday, November 18, 2002 9:54 AM
> >Subject: RE: OSPF Virtual link cross Multi area
> >
> >
> > > Tasuka,
> > >
> > > As long as you have a valid virtual-link to area 0 from area 20, then
> >you
> > > can "virtual-link" to the area 20 router with the link to area 0.
> > > Any contrary views?
> > >
> > > Bashir
> > >
> > > -----Original Message-----
> > > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> > > Tasuka Amano Hsu
> > > Sent: 18 November 2002 13:42
> > > To: ccielab Groupstudy
> > > Subject: OSPF Virtual link cross Multi area
> > >
> > > If a network topology like below:
> > >
> > > Area 0---Area 10---Area 20--Area 30
> > >
> > > How to make the virtual linke from Area 30 to connect to Area 0
> > >
> > > And I could make a virtual link for area 20 to through area 10 to
> > > connect to area 0 but how about area 30 ?
> > >
> > > Best Regards
> > >
> > > Tasuka
>
>
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