Subject: RE: [speechsc] Grammar freshness checking on RECOGNIZE

From: "Shanmugham, Saravanan" <[email-masked]>
Date: Mon, 17 Apr 2006 14:28:37 -0700

I would like to refer to a proposed clarification on grammar storage Vs
caching I sent out in reponse to calrification request from Jerry
Carter. This attempts to calrify the differennce between caching and
storage.

When you are refering to pre-defined grammar, I am assuming you are
talking about "session:" grammars, because those are the ones that are
STORED and don't get CACHED-OUT. Any other external grammars refered
through a URI, are essentially cached and hence would be following cache
control parameters specified for the session or request. So if they are
stale they would get cachedout and hence reloaded. 
I could further clarify that this cache staleness should happen at both
DEFINE-GRAMMAR and RECOGNIZE commands.

Does this clarification address your concern.

Thx,
Sarvi 

     -----Original Message-----
     From: Andrew Wahbe [mailto:[email-masked]] 
     Sent: Monday, April 17, 2006 9:59 AM
     To: IETF SPEECHSC (E-mail)
     Subject: [speechsc] Grammar freshness checking on RECOGNIZE
     
     The VoiceXML Forum MRCP Liaison Committee is concerned 
     that seems to be no mention of the freshness of previously 
     defined grammars being evaluated on a RECOGNIZE. For 
     example, consider a long session where a grammar X was 
     defined at the start of the session and X was used in a 
     recognition at the end of the session. If the grammar 
     expired at some point in between, the session would be 
     using an "old", expired version of the grammar for the recognition.
     
     The SRGS specification indicates in section 4.14 that this 
     check should be done:
     
     "Activation of a grammar is the point at which the 
     recognizer begins detection of user input matching the 
     grammar and is therefore analogous to the action of visual 
     or audio rendering of system output. As with output 
     rendering, grammar freshness should be checked close to 
     the moment of grammar activation."
     
     A statement should be added to the specification requiring 
     that the freshness of pre-defined grammars should be 
     checked on a RECOGNIZE and that expired grammars should be 
     re-fetched and re-compiled.
     
     Thanks,
     
     Andrew Wahbe
     VoiceXML Forum MRCP Liaison Committee

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From: Andrew Wahbe <[email-masked]>
Date: Mon, 17 Apr 2006 18:07:16 -0400

Actually I am referring to external grammars referenced via URI and not 
to "session:" grammars. This "caching out" behavior you refer to is 
related to the behavior that I would like clarified. I don't think it is 
said explicitly anywhere that grammar freshness should be evaluated on a 
RECOGNIZE and if the grammar is stale, it should be re-fetched and 
re-compiled. This is done even if we haven't run out of room in our 
cache and needed to purge old stuff (The "caching out" text in your 
clarification seemed to be focusing on this case). Sorry if it is there 
in the spec or your clarification and I missed it.

There is definitely text that is related to the issue in 6.2.10 and 
6.2.12. It is just not explicit. Since we are fetching and using the 
grammars in two separate steps here, DEFINE-GRAMMAR and RECOGNIZE, I 
think it is worth calling out that the evaluation needs to take place on 
both steps.

Andrew