From: stiff (stiff.yu@xxxxxxxxxxxxxxxxxx)
Date: Sat May 20 2000 - 02:37:21 GMT-3
hi,
I think you must use ABR and area range summary /28 /30 to /24.
-----Original Message-----
From: Goh, Winston <winston.goh@sg.unisys.com>
To: 'Adwait Tare' <adwait_tare@yahoo.com>; ccielab@groupstudy.com
<ccielab@groupstudy.com>
Date: 2000Äê5ÔÂ19ÈÕ 9:40
Subject: RE: OSPF summarisation / path selection on 2 ABRs
>Hi Adwait,
>ospf supports equal cost load-balancing. If you wish r2 to route once r1
>failed, it is done dynamically due to link-state changes, it will
>re-converge. As for your question on routing via r1 instead of r2, changing
>the cost using ip ospf cost or bandwidth on the interface. Maybe do a shut
>and no shut on that interface to force for a re-convergence and
>re-calculation for the new cost to take effect. Alternatively, set R1 as
the
>DR using ip ospf priority. Policy routing can also used. As for your
>question on summarization, do a area range on the ABR whichever routers is
>being the next hop into area 1 from the perspective of area 0 router.
cheers
>
>
>Winston Goh
>CCNP, CVE
>Snr Network Specialist
>Unisys Singapore
>mobile : 97469192
>
>
>-----Original Message-----
>From: Adwait Tare [mailto:adwait_tare@yahoo.com]
>Sent: Friday, May 19, 2000 5:32 AM
>To: ccielab@groupstudy.com
>Subject: OSPF summarisation / path selection on 2 ABRs
>
>
>
> AREA1/VLAN1
> --------------------
> |e0 |e0
> (R1) (R2)
> |s0 |s0
> | AREA0/FR |
> | |
> ------------------
> |s0.1 point to multipoint
> (R3)
>
>In this topology, If I have to send the traffic over
>R1 to VLAN1 always and sent over R2 only in case R1
>fails.. How do I do it. I have tried to give high IP
>OSPF COST at the s0 of R1,s0.1 on R1 and e0 of R1, but
>did not help. Always the traffic is going over only
>R2. I have done interarea summarisation over R1 and R2
>between area 1 and area 0. I have 'no ip route-cache'
>over all the interfaces. The problem is when I shut
>the interface e0 of R2 to check if the traffic now
>takes the route through R1 to reach VLAN1, it does not
>do that. The packets still try to go over to R2 and
>get lost.
>
>I am confused over the operation of 2 ABRs connecting
>same NON-Backbone area (area1) to Backbone area
>(area0).
>
>Are there any special considerations for interarea
>summarisation when you are using 2 ABRs to connect to
>area O.
>
>Any good place to read about these kinds of issues.
>
>Thakns in advance.
>
>Adwait
>
>
>
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