From: k c (jwongccie@yahoo.com.hk)
Date: Fri Dec 19 2003 - 12:02:48 GMT-3
I also looked into it last year. It is possible with routes learned from same AD/metric. Examples are using 2 ospf processes on same router and learning same routes externally via E2. Each ospf process learns same E2 route with same AD/metric. The one who learned the route first will install the route. U can test it.
David Hiers <David_Hiers@adp.com> wrote:I looked into this about a year ago. Results were vague, and there was no documentation that covers routes selection when different protocols have the same AD. I tested with OSPF and EIGRP having equal AD, and things were simply weird.
David
********************************************
David Hiers
CCIE, CISSP
ADP Dealer Services
2525 SW First Avenue
Portland, OR 97201
v: 503 402 3703
email: david_hiers@adp.com
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-----Original Message-----
From: William Chen [mailto:kwchen@netvigator.com]
Sent: Wednesday, December 17, 2003 5:44 AM
To: Jung, Jin; ccielab@groupstudy.com
Subject: Re: Routes learnt by routing protocols with same AD/metric
Hi Jin,
I tried the variance command, but don't work.
They are learnt from different EIGRP AS, I think variance only work for
routes learnt from same AS.
I also tried that if I change from AS30 to AS300, the routes in AS40 are
perferred.
- William Chen
----- Original Message -----
From: "Jung, Jin"
To: "'William Chen'" ;
Sent: Wednesday, December 17, 2003 9:33 PM
Subject: RE: Routes learnt by routing protocols with same AD/metric
> First, you should not get same AD same metric from different routing
> protocol, unless you change the default and make it so, which could be a
lot
> of work,,
> OSPF uses different AD and different metric calculation verses EIGRP.
>
> For you question in regards to EIGRP in different AS.
> Look up "variance" command.
>
> By default its 1,
> You can change that with above command,,and you will get load balancing.
>
>
>
> > Jin Jung CCIE#12368
> > Network Infrastructure Engineer
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> William Chen
> Sent: Wednesday, December 17, 2003 2:18 AM
> To: ccielab@groupstudy.com
> Subject: Routes learnt by routing protocols with same AD/metric
>
>
> Dear all,
>
> I think it should be a simple question, but I just never think about
it.
>
> If a route is learn from different routing protocol with same AD, and
> same metric. What is the preference order? Is there any doc talking about
> that?
>
> Look at the following example of a router running EIGRP AS30/EIGRP AS40
> and learn same routes. Can I make the router to load balancing the routes?
>
> CAT1#sh ip eigrp top
> IP-EIGRP Topology Table for AS(30)/ID(223.1.1.1)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 172.16.200.0/22, 1 successors, FD is 281856
> via Summary (281856/0), Null0
> P 172.16.201.0/24, 1 successors, FD is 281856
> via 172.16.30.20 (281856/25856), Vlan30
> P 172.16.202.0/24, 1 successors, FD is 281856
> via 172.16.30.20 (281856/25856), Vlan30
> P 172.16.203.0/24, 1 successors, FD is 281856
> via 172.16.30.20 (281856/25856), Vlan30
> P 172.16.30.0/24, 1 successors, FD is 281600
> via Connected, Vlan30
> P 172.16.120.0/24, 1 successors, FD is 281856
> via 172.16.30.20 (281856/25856), Vlan30
> P 172.16.110.0/24, 1 successors, FD is 25856
> via Rconnected (25856/0)
> IP-EIGRP Topology Table for AS(40)/ID(223.1.1.1)
>
> Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
> r - reply Status, s - sia Status
>
> P 172.16.201.0/24, 0 successors, FD is Inaccessible
> via 172.16.40.20 (281856/25856), Vlan40
> P 172.16.202.0/24, 0 successors, FD is Inaccessible
> via 172.16.40.20 (281856/25856), Vlan40
> P 172.16.203.0/24, 0 successors, FD is Inaccessible
> via 172.16.40.20 (281856/25856), Vlan40
> P 172.16.40.0/24, 1 successors, FD is 281600
> via Connected, Vlan40
> P 172.16.120.0/24, 0 successors, FD is Inaccessible
> via 172.16.40.20 (281856/25856), Vlan40
> P 172.16.110.0/24, 1 successors, FD is 25856
> via Rconnected (25856/0)
>
> CAT1#r
> Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP
> D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
> N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
> E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP
> i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
> area
> * - candidate default, U - per-user static route, o - ODR
> P - periodic downloaded static route
>
> Gateway of last resort is not set
>
> 1.0.0.0/24 is subnetted, 1 subnets
> C 1.1.1.0 is directly connected, Loopback84
> C 223.1.1.0/24 is directly connected, Loopback83
> 172.16.0.0/16 is variably subnetted, 8 subnets, 2 masks
> D 172.16.200.0/22 is a summary, 00:07:22, Null0
> D EX 172.16.201.0/24 [170/281856] via 172.16.30.20, 00:07:22, Vlan30
> D EX 172.16.202.0/24 [170/281856] via 172.16.30.20, 00:07:22, Vlan30
> D EX 172.16.203.0/24 [170/281856] via 172.16.30.20, 00:07:22, Vlan30
> C 172.16.40.0/24 is directly connected, Vlan40
> C 172.16.30.0/24 is directly connected, Vlan30
> D EX 172.16.120.0/24 [170/281856] via 172.16.30.20, 00:07:23, Vlan30
> C 172.16.110.0/24 is directly connected, Loopback110
> 129.1.0.0/24 is subnetted, 1 subnets
> C 129.1.1.0 is directly connected, Loopback82
> 126.0.0.0/24 is subnetted, 1 subnets
> C 126.1.1.0 is directly connected, Loopback81
>
> Best Regards,
> William Chen
>
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