From: Carlos G Mendioroz (tron@xxxxxxxxxxx)
Date: Mon May 06 2002 - 10:06:01 GMT-3
Lan is between R1 and R2. I assumed full FR mesh, but this is not
that important I guess.
R3---A0
/ \
A1 A1
/ \
R1--A1--R2
| |
|--A2----|
ying chang wrote:
>
> If I understand Steven's topology correctly, I cannot see why not. The way I
> see his topology is like below:
>
> R1
> / \
> A1 A1
> / \
> R2 R3---A0
> | |
> |--A2----|
>
> A1 is in the Frame Relay cloud, A2 and A0 are in LAN interfaces, if R1-R3 FR
> link fails, he wants be able to reach A0 via R1-R2-R3 link. If this is the
> case, I see it's a perfect case for virtual link between R1 and R3 just by
> cutting the link betwwen R1-R3 link:
>
> R2:
>
> router ospf 100
> ...
> area 2 virtual-link R3's RID
> ...
>
> R3:
>
> router ospf 100
> ...
> area 2 virtual-link R2's RID
> ...
>
> Since the error message is referring to RID mismatch, I would use "show ip
> ospf" to find both R2 and R3's RID. I'm guessing he probably peering R1 and
> R3 instead of R2 and R3, but I'm not sure.
>
> Actually, if you want to get fancy, you can use A1 to backup A2 as well.
> i.e. A2 is the primary route for R2 to reach A0, but if A2 fails, R2 should
> be able to use A1 to reach A0.
>
> Chang
>
> >From: Carlos G Mendioroz <tron@huapi.ba.ar>
> >Reply-To: Carlos G Mendioroz <tron@huapi.ba.ar>
> >To: steven owen <trueccie@yahoo.com>
> >CC: Groupstudy ccielab list <ccielab@groupstudy.com>
> >Subject: Re: ospf virtual link
> >Date: Mon, 06 May 2002 07:52:00 -0300
> >
> >Steven,
> >virtual links are always area 0.
> >They are use to make up for the need of area 0 being THE
> >connecting area (aka backbone) and in one piece.
> >Tipical uses have one end in real area 0, and the other in
> >a remote (i.e. non directly connected) area, but it also
> >can be used to reattach a disconnected area 0 sector
> >(thus both ends lying in area 0).
> >
> >Now, answering you question, no, you can not.
> >(Also you need not, since it is ok for having more than
> >one area X at one time.)
> >What you do need is having area 2 directly connected to
> >area 0, and there you can (should) use one or two
> >VLs to go via area 1.
> >
> >steven owen wrote:
> > >
> > > I GOT r1,r2,r3 connected by FR,all the interfaces on
> > > FR are on area 1,r1 and r2 have an ethernet int each
> > > ,which is on area 2,r3 have an int on area 0.
> > > Can i build a vl between r1 ,r2 on area 2 to backup
> > > area 1 link if FR is down?
> > > and before i build vl,r1 always receives such the
> > > following error message:
> > > "%OSPF-4-ERRRCV: Received invalid packet: mismatch
> > > area ID, from backbone area must be virtual-link but
> > > not found from 20.4.1.1, FastEthernet1/0"
> > > but r2 doesn't have an int on area 0.Why?
> > >
> > > Thanks.
> > >
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