From: Stefan Grey (examplebrain@hotmail.com)
Date: Sun Sep 25 2005 - 12:44:43 GMT-3
Hello guys,
thanks to all how replyed on my problem. Here are some new things:
1st. I don't think that it is a problem that the intra area route is more
prefered than the inter area routes. This is because a I think both routes
area Inter ARea. One is through Area 0 second through Area 1 and the origin
of the route is in Area 3.
2nd. What happens, just for
>kicks, if you add on R2 "area 1 virtual-link <R3 RID>" and on R3 "area 1
>virtual-link <R2 RID>"?What happens, just for
When I configrued the virtual link between R3 and R2. The route through R2
bacame more prefereble as it should be. (the metric 76).
When both routes area through area 0 the second route is more preferable.
3rd. The behaviour is like following: The router chooses the route through
Area 0 to Area 3. The router thinks that it is better than to Area 1 than to
ARea 0 and than to area 3.
Although both routes area interarea and the metric for second route is
better.
Strange not?? What do you think about it?? Maybe OSPF have something like
as-path for areas :):) ??
So to sum up. How ospf makes a dicision about the best route???
1. Inter area , intra area, outside route
2. AD
3. Metric
Which other criterea in my case??
Thanks,
>From: "Jaycee Cockburn - BCX SS" <Jaycee.Cockburn@bcx.co.za>
>Reply-To: "Jaycee Cockburn - BCX SS" <Jaycee.Cockburn@bcx.co.za>
>To: "Stefan Grey" <examplebrain@hotmail.com>, <ccielab@groupstudy.com>
>Subject: RE: VERY INTERESTING OSPF behaviour??
>Date: Sun, 25 Sep 2005 16:41:38 +0200
>
>Hi Stefan,
>I think this has to do with OSPF prefering the intra area routes before
>inter area routes. Area 0 routes being the backbone area will, I
>suppose, be prefered over other area's routes. What happens, just for
>kicks, if you add on R2 "area 1 virtual-link <R3 RID>" and on R3 "area 1
>virtual-link <R2 RID>"?
>
>Cheers
>JC
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Stefan Grey
>Sent: 25 September 2005 04:25 PM
>To: ccielab@groupstudy.com
>Subject: VERY INTERESTING OSPF behaviour??
>
> Hi, group,
>I see such behaviou the first time:
>
> R4
> |
> |
> R1------R2
> | __ |
> | _|
> | |
> R3----
>
>
>
>
>Between R1 and R4 is area 3, between router R3 and R1 area 0. Between R1
>and
>R2 area 0. connection between R3 - R2 area 1. As to physical
>connections:
>between R1 and R4 ethernet, between R3 and R2 ethernet. Between R1,R2
>nbma frame-relay, between R1 -R3 ISDN. Everything is configured
>correctly. R3 gets two routes about lo0 of R4 from R1 and R2.
>on R1 is configured the ip ospf 9999 command to make this route less
>preffereable than from R2. But what strange thing wee see:
>
>
>O IA 1.1.6.6/32 [110/10001] via 1.1.35.5, 00:17:32, BRI0/0
>I wonder why the less prefereble route is used?? Ok I turn of the bri0/0
>interface and look which other route I get from router R2.
>
>O IA 1.1.6.6/32 [110/76] via 1.1.23.2, 00:00:29, Ethernet0/1
>This route is the same as previous but with much better metric. Why it
>is not choosed?? But the worther one is choosed??
>
>
>Thanks,
>
>The only one advantage of the route through R1 is that R1 - R3 is in
>AREA0.
>But as we know the route is choosed just in two criterias AD/ Metric.
>I am totally confused with this.
>
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