Subject: RE: [Sipping] indicating SMS capability in REGISTER

From: "Gaurav Kheterpal" <[email-masked]>
Date: Wed, 22 Feb 2006 03:54:16 -0800

Jeroen,

Interesting thought :-). I've also off-late been trying to figure out
the SIP-SMS mythology. Anyway, as per my understanding, the SMS
capability is usually not handled by the proxy itself. The proxy
interacts with a dedicated SMS gateway (may/ may not be same host) for
this purpose. I managed to dig out some related info from SER's public
documentation - which might be useful for you :

"1.1.3. Address Mapping

To identify the destination number of the SMS, the gateway expects to
have a mobile number in username of the SIP destination address (for
example sip:[email-masked]). For the reverse direction, because
the gateway has only one GSM number, the destination SIP address has to
be encapsulated into the SMS body. The gateway expects to find a SIP
address at the beginning of the SMS body in "sip:user.host" format.
Everything before the SIP address will be discarded, the useful text
begins exactly after the address (for example SMS="For sip:user@host
hello world!!" -> SIP="hello world") In order to facilitate replying,
the gateway sends all the SMS messages with a header containing the
source SIP address in the following format: "From sip:user@host (if you
reply DONOT remove it)<new_line>". When an SMS-reply is received having
this header (all of it or truncated at the end), the header will be left
out (it will not be in the SIP message). "

Since the intended recipient for normal calls (voice or otherwise -
proxy) will be different from SMS gateway (messages) before it reaches
the destination, so I think this should resolve the confusion of
"sending a SMS to a number" or "calling a number". Anyway, since the
ENUM translation can lookup a sms: URI (and map it to a tel URI), so a
message can be sent with a sms: scheme in the Request URI while a normal
call can be made with a tel:/ sip: URI.

Check out the description on
http://www.iptel.org/ser/doc/modules/html/sms.html

I hope this helps.

Regards,
Gaurav

________________________________

From: Jeroen van Bemmel [mailto:[email-masked]] 
Sent: Wednesday, February 22, 2006 4:36 PM
To: sipping
Subject: [Sipping] indicating SMS capability in REGISTER

I am looking for best practice guidance on the following: suppose I have
a PDA that supports circuit switched calls as well. In my SIP softphone
I'd like to indicate the device's capability to be called on CS, and
also to receive SMS.

My initial thought was as follows:

REGISTER ...

Contact: sip:ip:host

Contact: tel:+1-201-555-0123

Contact: sms:+1-201-555-0123

However, "sms" is not an official URI scheme. RFC4355
(http://www.ietf.org/rfc/rfc4355.txt) defines "sms" as an enum service,
using the "tel" URI scheme. My question is: how would one indicate the
SMS capability in this case? (for SIP URIs, I imagine one would use
RFC3840 capabilities)

Related question for a clickable link in a webpage: How would one
distinguish between "send an SMS to this number" and "call this number"?

Regards,

Jeroen van Bemmel

_______________________________________________
Sipping mailing list  https://www1.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use [email-masked] for questions on current sip
Use [email-masked] for new developments of core SIP

---

From: "Jeroen van Bemmel" <[email-masked]>
Date: Wed, 22 Feb 2006 13:07:21 +0100

Gaurav,

Thanks for your response. I just found this draft http://www.ietf.org/internet-drafts/draft-wilde-sms-uri-11.txt which specifies "sms" as a valid URI scheme, I did not know it was in the process of being standardized.

Regards,

Jeroen
  ----- Original Message ----- 
  From: Gaurav Kheterpal 
  To: Jeroen van Bemmel ; sipping 
  Sent: Wednesday, February 22, 2006 12:54 PM
  Subject: RE: [Sipping] indicating SMS capability in REGISTER

  Jeroen,

  Interesting thought J. I've also off-late been trying to figure out the SIP-SMS mythology. Anyway, as per my understanding, the SMS capability is usually not handled by the proxy itself. The proxy interacts with a dedicated SMS gateway (may/ may not be same host) for this purpose. I managed to dig out some related info from SER's public documentation - which might be useful for you :

  "1.1.3. Address Mapping
  To identify the destination number of the SMS, the gateway expects to have a mobile number in username of the SIP destination address (for example sip:[email-masked]). For the reverse direction, because the gateway has only one GSM number, the destination SIP address has to be encapsulated into the SMS body. The gateway expects to find a SIP address at the beginning of the SMS body in "sip:user.host" format. Everything before the SIP address will be discarded, the useful text begins exactly after the address (for example SMS="For sip:user@host hello world!!" -> SIP="hello world") In order to facilitate replying, the gateway sends all the SMS messages with a header containing the source SIP address in the following format: "From sip:user@host (if you reply DONOT remove it)<new_line>". When an SMS-reply is received having this header (all of it or truncated at the end), the header will be left out (it will not be in the SIP message). "

  Since the intended recipient for normal calls (voice or otherwise - proxy) will be different from SMS gateway (messages) before it reaches the destination, so I think this should resolve the confusion of "sending a SMS to a number" or "calling a number". Anyway, since the ENUM translation can lookup a sms: URI (and map it to a tel URI), so a message can be sent with a sms: scheme in the Request URI while a normal call can be made with a tel:/ sip: URI.

  Check out the description on http://www.iptel.org/ser/doc/modules/html/sms.html

  I hope this helps.

  Regards,
  Gaurav

------------------------------------------------------------------------------

  I am looking for best practice guidance on the following: suppose I have a PDA that supports circuit switched calls as well. In my SIP softphone I'd like to indicate the device's capability to be called on CS, and also to receive SMS.

  REGISTER ...

  Contact: sip:ip:host

  However, "sms" is not an official URI scheme. RFC4355 (http://www.ietf.org/rfc/rfc4355.txt) defines "sms" as an enum service, using the "tel" URI scheme. My question is: how would one indicate the SMS capability in this case? (for SIP URIs, I imagine one would use RFC3840 capabilities)

  Related question for a clickable link in a webpage: How would one distinguish between "send an SMS to this number" and "call this number"?

  Regards,

  Jeroen van Bemmel