Re: Redistribution Problem

  Woops forgot to add the answer to your question.

The router will only choose use the routes for a prefix from one routing
protocol because that way it can guarantee at least for that AS it has a
loop free path for the prefix (of course redistribution can negate
that). But if the router where to install one route from one AS and
another from a second AS it wouldn't be able to be sure that the path
doesn't loop somewhere as the two AS's don't share routing information.

So it looks like the router chooses the lowest AS number when the prefix
length and AD are the same for a prefix.

On 27/08/2010 3:05 PM, Vince Librandi wrote:
> Hi Hemanth,
>
> I just lab'ed up your set up and got the same affect. Looks like when
> you have two EIGRP process and the metric is the same and the AD on
> the route is the same the router chooses the process with the lowest
> AS number. Just to prove it I configured another EIGRP process (AS 50)
> on the R5-R4 link and the router choose that path instead.
>
> R5(config-router)#do sh ip ei top
> IP-EIGRP Topology Table for AS(100)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32, 0 successors, FD is Inaccessible
> via 10.1.35.3 (3097600/2585600), Serial0/1
>
> IP-EIGRP Topology Table for AS(200)/ID(1.1.1.2)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32, 0 successors, FD is Inaccessible
> via 10.1.45.4 (3097600/2585600), Serial0/0
>
> IP-EIGRP Topology Table for AS(50)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32, 1 successors, FD is 3097600
> via 10.1.45.4 (3097600/2585600), Serial0/0
>
>
>
> but if both links are in the same AS then I get the load balancing
>
> R5(config-router)#do sh ip ei top
> IP-EIGRP Topology Table for AS(100)/ID(10.1.45.5)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 1.1.1.1/32, 2 successors, FD is 3097600
> via 10.1.35.3 (3097600/2585600), Serial0/1
> via 10.1.45.4 (3097600/2585600), Serial0/0
>
> Looks like this is the way the routing table chooses between routes
> handed to it from different processes.
>
> Must see if OSPF does the same thing.
>
> Regards
>
> Vince
>
>
> On 27/08/2010 1:21 PM, HEMANTH RAJ wrote:
>> s0/1 s0/0
>> R2-------------------R3\s 0/2
>> | | \
>> |s0/0 s0/3 | \
>> | | \ R1-loo 0
>> 1.1.1.1/24
>> | | \ s 0/0 R1-loo 1
>> 11.11.11.11/24
>> | | \
>> | | / R5 R2-loo o
>> 2.2.2.2
>> /24
>> | | / R2-loo 1
>> 22.22.22.22/24
>> | | / s 0/1
>> | | /
>> | s0/0 | /
>> | s0/3 | /s0/2
>> R1-------------------R4
>> s0/1 s0/0
>>
>>
>>
>>
>>
>> I'm running ospf area 0 on R1,R2,R3 s 0/0,R4 s0/0
>>
>> R3 s0/3 ospf area 20
>> R4 s0/3 ospf area 20
>>
>> R3 s0/2 eigrp AS 100
>> R5 s0/0 eigrp AS 100
>>
>> R4 s0/2 eigrp AS 200
>> R5 s0/1 eigrp AS 200
>>
>>
>> I have done mutual redistribution on R3 between OSPF and EIGRP 100
>>
>> I have done mutual redistribution on R4 between OSPF and EIGRP 200
>>
>> Every route can ping every other route
>>
>> But when i check on R5 routing table I'm learning R1's loopback0 via R3
>>
>> But as per the logic it should load balance between R3 and R4 but it is
>> choosing only R3
>> and when i check on R5 topology table it shows the route via R4 is
>> inaccessible
>>
>> I have reidstributed from opsf to eigrp with same metric on both R3
>> and R4
>>
>> R3
>> router eigrp 100
>> redis ospf 1 met 1 1 1 1 1
>>
>> R4
>> router eigrp 200
>> redis ospf 1 met 1 1 1 1 1
>>
>> But still R5 is choosing path via R3 and not loadbalancing between R3
>> and R4
>>
>> Can anyone help me out of this issue???
>
>
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Received on Fri Aug 27 2010 - 15:35:53 ART