Re: Two queries on calculating AS external routes

Paresh Khatri <Paresh.Khatri@AAPT.COM.AU> Sun, 10 July 2005 23:51 UTC

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From: Paresh Khatri <Paresh.Khatri@AAPT.COM.AU>
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Thanks for all your replies, guys.


-----Original Message-----
From: Mailing List [mailto:OSPF@PEACH.EASE.LSOFT.COM]On Behalf Of Acee
Sent: Sunday, 10 July 2005 03:16 AM
Subject: Re: Two queries on calculating AS external routes

Pat Murphy - (650)329-4044 wrote:

>>In my case below, what if the two LSAs are not quite
>>functoinally equivalent i.e what if the LSAs have the same
>>destination, same cost etc but have different non-zero
>>forwarding addresses ? What happens then ?  Do the same
>>tie-breaker rules apply or will it be implementation-dependent ?
>The tie breaker rules are not applied. Here the installation 
>decision process is the same regardless of whether it is 
>comparing two Type 5 LSAs, or a Type 5 and a Type 7 LSA, or two 
>Type 7 LSAs. Whether or not both are installed depends on the 
>pruning done in step (c) as defined in RFC 2328 Section 16.4.1.
Conceivably, you still could end up with LSAs with differing forwarding 
addresses of equal
cost and equivalent path preference for the prefix. I don't believe this 
case is covered. However,
since the forwarding address costs are equal, I don't think there should 
be any loops.


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