Re: OSPF filtering

Yes, I considered GRE tunnel between area 212 across area 0. I tried
that and it doesn't work. Reason is cause one of the locations (right
one on the diagram) is already connected with area 0 via GRE tunnel,
because on that location between area 212 and area 0 is another area.
When I configure GRE to directly connect area 212 my tunnel is going
up/down.
Only thing cross my mind is to configure floating static routes in
metro backup cloud, but that is not some solution...

On Sat, Jan 23, 2010 at 7:05 AM, Petr Lapukhov
<petr_at_internetworkexpert.com> wrote:
> Ivan,
>
> The design you selected "against" the rules of OSPF multi-area
> routing. However, a very similar situation is often faced in
> multihomed MPLS/BGP VPN OSPF scenarios. The solution used there is
> known OSPF sham link. However, essential features needed for the sham
> link are the MPLS LSP available to tunnel packets between the
> connecting ABRs and BGP VPNv4 prefixes propagation (actual routing is
> done based on BGP forwarding information).
>
> As an equivalent solution for an IP-only network, you may consider
> running a Layer 3 tunnel between Area 212's ABRs and across Area 0
> configuring it as an Area 212 link. This will automatically make any
> paths calculated for Area 212 across the tunnel seen as intra-area
> routes for Area 212 routers. By adjusting the tunnel OSPF cost you may
> steer traffic to flow across the backbone area. The tunnel is
> necessary as backbone OSPF routers (non Area 212's ABRs) may have no
> idea about topology for Area 212.
>
> Naturally, this solution has some drawbacks from both design (topology
> is less clear and harder to troubleshoot) and implementation
> standpoint (e.g. MTU issues). You may also consider other tunneling
> options, e.g. layer 2 tunnels or layer 2 PVCs between the ABRs (if the
> underlying infrastructure supports that).
>
> HTH
> --
> Petr Lapukhov, petr_at_INE.com
> CCIE #16379 (R&S/Security/SP/Voice)
>
> Internetwork Expert, Inc.
> http://www.INE.com
> Toll Free: 877-224-8987
> Outside US: 775-826-4344
>
> 2010/1/22 Ivan Hrvatska <ivanzghr_at_gmail.com>:
>> Anybody?
>>
>> On Fri, Jan 22, 2010 at 4:15 PM, Ivan Hrvatska <ivanzghr_at_gmail.com> wrote:
>>> Hi,
>>>
>>> I have situation (see pic) where my traffic goes through backup links
>>> because it is same area. It should go through area 0. I cannot change
>>> the fact that area 212 is stub and I cannot influence on areas. What
>>> can I do to make traffic goes through area 0 between Location 1 and
>>> Location 2? In area 0 ABR routers summarize networks and filter out
>>> only summarize networks originated in Area 0. Also, they advertise to
>>> Location 1 only summarized route to Location 2 and vice verse.
>>> My question is how can I manipulate in this design so that transit
>>> through area 0 should be PRIMARY and through ME backup only if primary
>>> fails.
>>>
>>> Regards
>>
>>
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Received on Sat Jan 23 2010 - 11:31:55 ART