From: Goh, Winston (winston.goh@xxxxxxxxxxxxx)
Date: Thu May 18 2000 - 22:10:59 GMT-3
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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