M3UA - What state for AS in loadshare mode?

Peter Woodhouse <[email protected]>
Newsgroups gmane.ietf.sigtran
Organization Artesyn Communications Products
Message-ID <[email protected]>
I have a question regarding the state of the AS in an N+K redundancy 
model and the sending of NTFYs.

Consider the situation where the AS requires 2 ASPs to be active before 
the AS is considered active when operating in loadshare mode.
Both ASPs are brought into an ACTIVE state.

What happens when one of the ASPs becomes INACTIVE?  The RFC doesn't 
appear to be clear.
It looks like we should send a NTFY (Insufficient resources).
If the AS state goes to PENDING and then to INACIVE after Tr, we should 
also send a NTFY (PENDING) as well?

The other 2 possibilities are
1) The AS state goes straight to INACTIVE - we send a NTFY (INACTIVE)
2) The AS state stays ACTIVE - this would seem a bit strange to me. Why 
would you consider the AS ACTIVE when you only have 1 ACTIVE association 
when associations are becomeing INACTIVE, but consider the AS INACTIVE
when associations are coming up?

 From the state transition diagram Figure 4, it implies we should always 
go PENDING then INACTIVE. However, the text in 4.3.2 states "AS-PENDING: 
An active ASP has transitioned to ASP-INACTIVE or ASP DOWN and it was 
the last remaining active ASP in the AS."
Additionally in 4.3.4.4 "If no other ASPs in the Application Server are 
in the state ASP-ACTIVE, the SGP MUST send a Notify message 
("AS-Pending") to all of the ASPs in the AS which are in the state 
ASP-INACTIVE.

So in summary, what NTFY messages should be sent and what state is the 
AS when one of the associations becomes INACTIVE.

Pete
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