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Re: Issue 012: EPR Lifetime

From: Francisco Curbera <curbera@us.ibm.com>
Date: Wed, 3 Nov 2004 12:30:41 -0500
To: "Bob Freund" <Bob.Freund@hitachisoftware.com>
Cc: public-ws-addressing@w3.org, public-ws-addressing-request@w3.org
Message-ID: <OFDB5F2A26.1D7CFE18-ON85256F41.005FA0B6-85256F41.006031C9@us.ibm.com>




It seems clear that one could build not one but many mechanisms for
managing the lifecycle of EPRs. As a general approach I think WS-Addressing
should not endorse a particular one (which one and why?), rather it should
enable other specifications to define their own, so apart from maybe
refining the faults contained in Section 4 I think lifecycle mechanisms
fall outside of the scope of the WG.

Paco




                                                                                                                                               
                      "Bob Freund"                                                                                                             
                      <Bob.Freund@hitachisoftw        To:       <public-ws-addressing@w3.org>                                                  
                      are.com>                        cc:                                                                                      
                      Sent by:                        Subject:  Issue 012: EPR Lifetime                                                        
                      public-ws-addressing-req                                                                                                 
                      uest@w3.org                                                                                                              
                                                                                                                                               
                                                                                                                                               
                      11/03/2004 07:39 AM                                                                                                      
                                                                                                                                               





Statement of issue:
At the moment there is no specification of the lifetime of an Endpoint
Reference.
What needs to be decided is:
      1)       Is there a need to provide a mechanism for management of EPR
      lifetime? If yes then what should it do?
      2)       Or: Is there a need to make some statement concerning an
      implied EPR lifetime? If yes then what?

Arguments Against:
      1)       The web has gone well enough up to now with the tacit
      assumption that uri’s live forever.
      2)       There is nothing like a 404 to indicate that the EPR you
      seek has gone missing. The service thus has complete control over
      expiration.
      3)       Much complexity especially in request-response MEPs. A lot
      of this complexity will arise from treatment of the case of EPRs
      expiring between receipt of request and receipt of response.  This
      complexity will extend to further complicate all protocols that
      permit the use of EPR expiration.

Arguments in Favor:
      1)       Provides a handy way for the EPR minter to control cache
      contents.



General Puzzlements:
      1)       Would EPRs compare equal if their expiration times were not
      equal?
      2)       If one received a message with an expired EPR in its to:,
      whan ought it to be dropped?
      3)       If one received an expired EPR in its replyto: ought the
      message be discarded?



Received on Wednesday, 3 November 2004 17:31:16 GMT

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