05-15-2008 03:55 AM - edited 03-05-2019 11:00 PM
When i look at the routing table of my OSPF router it shows lot of E1 and E2 routes.What is E1 and E2 routes.whate is the difference between them
Regards
Bava
05-15-2008 04:12 AM
Bava,
Please refer to the following document to find out what are the differences between the E1 and E2.
http://www.cisco.com/warp/public/104/3.html
Regards,
05-15-2008 04:20 AM
E1 routes indicate cumulative cost to reach the destination i.e. int indicates cost to reach ASBR + cost to destination from ASBR.
E2 route reflects cost only from the ASBR to destination. This is the default used by ospf for redistribution.
05-15-2008 04:52 AM
And if I may add to above replies, E2 is the default for redistribured routes.
HTH
Sam
PS:apologies , this was already covered.
11-28-2020 01:28 PM
Hello
Why E2 is the default ????
11-28-2020 01:55 PM
Hmm, don't know if something like "why" is documented by the OSPF group, but two possible reasons come to mind.
First, probably reduces some CPU load on the router, as it doesn't also have to calculate "cost" for an external route. (NB: CPU was a lot more constrained when these standards were initially done, then they are today.)
Second, possibly an assumption that you don't often have multiple paths to the ASBR, so often no need for a "cost" calculation at all.
11-28-2020 02:07 PM
Very good
Tanx for answer
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