Subject: Re: [sipcore] Summary of issues around registering feature tags

From: <[email-masked]>
Date: Mon, 4 May 2009 15:21:46 +0200

Thanks Cullen,

this solves some of the action points from the previous 3GPP - IETF telco (the good news)

Unfortunately it leaves more work to do (the bad news)

It seems best to close the AP's in 3GPP - IETF meeting later today, as this task will need to be carried out by someone who is willing to contribute and to drive the work in IETF.

BR,
Hannu Hietalahti
3GPP TSG CT Chairman
tel: +358 40 5021724

>-----Original Message-----
>From: ext Cullen Jennings [mailto:[email-masked]] 
>Sent: 29 April, 2009 20:13
>To: [email-masked]
>Cc: Robert Sparks; Gonzalo Camarillo; Hietalahti Hannu 
>(Nokia-CIC/Oulu); Adam Roach; Mary Barnes
>Subject: Summary of issues around registering feature tags
>
>
>3GPP has requested that IANA register two new feature tags
>(g.3gpp.icsi-ref and g.3gpp.iari-ref) in the global tree. Per
>RFC 2506 (Section 3.1.2), the policy for registrations in the
>global tree is expert review.
>
>This is the description of the feature tags to be registered:
>
>"Each value of the Application Reference media feature-tag 
>indicates the
>software applications supported by the agent. The values for this tag
>equal the IMS communication Service Identifier (ICSI) and IMS
>Application Reference Identifier (IARI) values supported by
>the agent. The Application Reference media feature tag is
>defined to fulfill the requirements for forking to an appropriate UE  
>when
>multiple UEs are registered and dispatch to an appropriate application
>within the UE based upon the IMS communication Service Identifier
>(ICSI) and IMS Application Reference Identifier (IARI) values as
>stated in 3GPP TS 23.228.  Multiple tag-values can be included in the
>Application Reference media feature-tag."
>
>Section 12.1 of RFC 3840 states that feature tags that are 
>applicable to
>SIP and whose meaning is only defined within that usage are to be
>registered in the SIP tree. Since these feature tags are to be 
>used only
>within the context of SIP, they would need to be registered in the SIP
>tree and not in the global tree. The policy for registrations 
>in the SIP
>tree is IETF Consensus. That is, registrations need to be documented in
>an RFC approved by the IESG.
>
>Regardless of the tree these feature tags would need to be registered
>in, the expert reviewer indicated that this tags will not 
>contain simple
>features but rather more complex services or feature sets. Therefore,
>the expert reviewer did not find it appropriate to register 
>them because
>Section 2.1 of RFC 2506 states that "media feature tags represent
>individual and simple characteristics" and that "each media feature tag
>identifies a single characteristic".
>
>Additionally, Section 6 of
>draft-ietf-sipping-service-identification-03.txt describes the 
>perils of
>performing declarative service identifications. The way these feature
>tags are described make them look as if they were going to be used to
>perform such declarative service identifications.
>
>Consequently, 3GPP is encouraged to submit an Internet Draft describing
>the use of these feature tags so that they can be registered in the SIP
>tree. Such Internet Draft needs to address the issues discussed in
>draft-ietf-sipping-service-identification-03.txt clarifying why these
>tags will not be used to perform declarative service identifications.
>
>Cullen <RAI AD>
>
>Thank you to the people that helped prepare this summary.
>
>