03-30-2006 07:05 AM - edited 03-03-2019 12:14 PM
Hi,
How does an ABR generate the cost for ospf summarised routes..?
03-30-2006 07:16 AM
Ammavan
According to RFC 2328 when an ABR summarizes a range of routes it examines the routes to be summarized and advertises the highest cost of the individual routes.
HTH
Rick
03-30-2006 07:32 AM
Rick,
Thats a good answer.
Can a user anyway manipulate the cost of the summarised route,in this case..?
Thanks in advance,
03-30-2006 08:33 AM
Ammavan
Other than being able to use the ospf cost interface command to manipulate the metric of the individual routes (make some other route have a higher cost, or make the current highest cost lower) I am not aware of any way that you can manipulate the cost of the the summarized route.
HTH
Rick
03-30-2006 09:25 AM
Rick/Ammavan,
My observation has been that IOS is not compliant with RFC2328 in this area. The metric used for the summarised routes by the ABR is the *lowest* of all the metrics of the routes being summarised.
Also, there *is* a way to manually set the summary for the summarised route using:
area
Hope that helps - pls rate the post if it does.
Paresh
03-30-2006 09:26 AM
Just another note: the cost keyword was added in IOS 12.2
Paresh
03-30-2006 11:58 AM
Paresh
Good observation.
Rick
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