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Janardhan Iyengar wrote:
>>>Switching over to an alternate on an FR may give you really good failover,
>>>but will likely hurt performance when there's no failure (the common
>>>case). Optimizing for the common case makes sense.
>>
>>Actually, if a failure occurs, you will not be able to fast rtx because
>>the ack clock will be lost. So switching to an alternate on an FR won't
>>even improve failover time.
>
>
> Yeah, good point. In fact, turning that reasoning around: when an FR
> does occur, since an ack clock exists, the ack clock demonstrates that
> there is no failure!
>
> To clarify, an FR occurs only when there are acks coming back; meaning
> data is getting through and so are acks. Therefore, failure couldn't have
> happened if an FR happens!
Well, we tested it with a real failure. To be honest, I have not looked
at that code in a long time. So maybe my follow-up comment was wrong.
I have to look into it.
Nonetheless, I do know that the switch-over occurs after the error count
on the primary is greater than zero, which gives better switch-over
performance. The lk-sctp switch-over time is unacceptable, IMHO.
--
David Lehmann Ulticom, Inc.
AOL/Yahoo IM: davidULCM 1020 Briggs Road
1-856-787-2729 Mt. Laurel, NJ 08054 USA
Received on Fri Feb 11 17:59:07 2005