From: ying chang (ying_c@xxxxxxxxxxx)
Date: Mon May 06 2002 - 09:16:11 GMT-3
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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