From: Howard C. Berkowitz (hcb@xxxxxxxxxxxx)
Date: Sat Feb 16 2002 - 15:36:53 GMT-3
At 10:54 AM -0600 2/16/02, Edward Moss wrote:
>Is there a general rule on how to handle redistribution into OSPF?
>For example, I believe the routes default to type 1 external routes where the
>metric is not increased internally.
>However type 2 external routes accumulate in the metric from hop to hop.
You have both the behavior and the default reversed.
Type 1: Sums internal and external costs
Type 2: Fixed external cost only. The default.
>
>My thought is any route inside my network that is being redistributed should
>be an E2.
>Only if the address is learned outside the network, flag it as E1.... unless
>there are multiple paths to the external route.
Well, I approach it somewhat differently. The two forms are there for
implementing policy, although not as complex as you can do with BGP.
If you have multiple E2 with different costs, you can specify the
order in which you want backup routes taken from any point in your
OSPF domain. Think of floating static routes as a parallel. It's
along the lines of best exit/cold potato.
When you have multiple E1 to the same external domain (e.g., ISP),
you can get a degree of load-sharing. It's essentially a closest
exit/hot potato model.
>
>Thoughts on the best way to approach redistribution into OSPF in regard to E1
>and E2 routes?
>
>Ed
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