10-16-2012 02:39 PM - edited 03-04-2019 05:52 PM
I have a problem or I'm just missing something which is the most likely scenario. I know that E2 routes should be preferred over N2 routes, unless the forward metric is lower for the N2 route. Is this correct?
I have two routers R1 and R2 that have a connection to each other via area 0 and area 10, area 10 is a totally NSSA. On R2 I redistribute a static route and expected that R1 would learn this route via area 0 as an E2 route instead it learns it as a N2 route via area 10. I need this traffic to flow over the area 0 link.
The area 0 link on both routers is 100 Mbps, the area 10 link is 1 Gbps, the link through which the static route points is also 100 Mbps and the reference bandwidth is 10 Gbps.
The N2 route has a metric of 20 in the routing table and when I look at the forward metric for this redistributed route it has a metric of 10 (1 gig link cost). When I fail the area 10 link, the E2 route appears in the routing table with a metric of 20 and when I look at the forward metric via area 0 it has a metric of 200 (100 meg area 0 link cost plus cost of exit interface for static route).
I understand the forward metric for the E2 route but why does the N2 route only consider the cost for the exit interace of the 1 Gbps link? Can anyone explain this? Is my only option to modify the cost to force it to use the area 0 link?
10-31-2017 08:41 AM
Dear Giuseppe,
Thanks for the reply on this topic. You are spot on regarding MTID, this seems like it is the default topology for IPV4.
There is a document which describes how to configure multiple topologies in OSPFV2, take note this has been implemented on 3.11S IOS-XE
Link:
Kind regards
Aleksandar Sofranic
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