Re: [Sip] SIP de-REGISTER: Expires header vs expires parameter i Contact

[Neelakantan Balasubramanian <[e-mail]>]

See RFC 3261 Section 10.2.1.1

10.2.1.1 Setting the Expiration Interval of Contact Addresses

   When a client sends a REGISTER request, it MAY suggest an expiration
   interval that indicates how long the client would like the
   registration to be valid.  (As described in Section 10.3, the
   registrar selects the actual time interval based on its local
   policy.)

   There are two ways in which a client can suggest an expiration
   interval for a binding: through an Expires header field or an
   "expires" Contact header parameter.  The latter allows expiration
   intervals to be suggested on a per-binding basis when more than one
   binding is given in a single REGISTER request, whereas the former
   suggests an expiration interval for all Contact header field values
   that do not contain the "expires" parameter.

Thanks,
Neel.

From: [e-mail] [mailto:[e-mail]] On Behalf Of Gert Olsson
Sent: Tuesday, January 20, 2009 6:26 AM
To: [e-mail]
Subject: [Sip] SIP de-REGISTER: Expires header vs expires parameter i Contact


Hi,

SIP de-registration is performed by sending a REGISTER message with either a Contact header containing an 'expires=0' parameter or an Expires header with value 0. My question is: is it FORBIDDEN to have both? Shouldn't any decent server, if it has found 'expires=0' in the Contact header (or in all if many), just happily ignore an Expires header?

[Neelakantan Bala]
See RFC 3261 Section 10.2.1.1

10.2.1.1 Setting the Expiration Interval of Contact Addresses

   When a client sends a REGISTER request, it MAY suggest an expiration
   interval that indicates how long the client would like the
   registration to be valid.  (As described in Section 10.3, the
   registrar selects the actual time interval based on its local
   policy.)

   There are two ways in which a client can suggest an expiration
   interval for a binding: through an Expires header field or an
   "expires" Contact header parameter.  The latter allows expiration
   intervals to be suggested on a per-binding basis when more than one
   binding is given in a single REGISTER request, whereas the former
   suggests an expiration interval for all Contact header field values
   that do not contain the "expires" parameter.

Thanks,
Neel.



br

/GO
__________________________________________________________________|
Gert Olsson   /  phone: [phone]   /  e-mail: [e-mail]
Ericsson AB - Business Unit Mobile Platforms, SE-221 83  Lund, Sweden

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