RE: [SIP] phone-context and RFC2543bis

[Dean Willis <[e-mail]>]

Alan,

I believe the existing SIP syntax allows for arbitrary URI parameters, so
there really aren't any syntactic changes needed.  The real question is the
semantics. I don't believe the semantics of which you want to use
"phone-contet" for have been discussed on the list.

I'd suggest you write your thoughts up as an ID and share them with us. I
think the basic idea sounds pretty good, but I'd like to see a more complete
framing of your intent.

--
Dean


> -----Original Message-----
> From: [e-mail]
> [mailto:[e-mail]]On Behalf Of Alan Johnston
> Sent: Friday, April 07, 2000 10:52 AM
> To: SIP
> Subject: [SIP] phone-context and RFC2543bis
>
>
> Based on reports from Adelaide, it sounds like the consensus of
> the working
> group was to progress the Call Flows I-D
> (draft-ietf-sip-call-flows-00.txt) to
> Informational RFC as soon as possible.
>
> One item that needs to be resolved first is the "phone-context"
> tag which is
> used extensively in the Gateway dialing sections of the document
> for private
> phone numbers (extensions).
>
> In RFC2543, support for phone numbers in SIP URLs was included by
> including
> parameters from the then current version of the Tel URL I-D if
> "user=phone" was
> present.  Since then, there have been additional drafts of this document
> (currently draft-antti-telephony-url-12.txt).
>
> One of the critical additions to the Tel draft since RFC2543 was
> the addition of
> the phone-context tag used for local numbers to identify the
> scope in which the
> number is valid.  I believe this tag needs to be included in SIP
> URLs in the
> next SIP draft.
>
> For example, the U.S. directory assistance telephone number can
> be written in
> global form as:
>
> 	sip:[e-mail];user=phone
>
> However, if the number was only valid if dialed from within the
> U.S., the number
> could be written as a local phone number as:
>
> 	sip:[e-mail];phone-context=+1
>
> Where the phone-context tag indicates that it is only valid from
> within country
> code 1.
>
> Another more compelling use of the phone-context tag is in
> dealing with private
> numbers - numbers that are not part of the public number space,
> but are part of
> a private numbering plan administered by a corporation or
> organization.  The
> examples in the Call Flows document are of this kind:
>
> 	sip:[e-mail];phone-context=mycarrier
>
> In this example, it appears that the host portion (gateway
> address) of the URL
> is sufficient to specify the context of the private number.
> However, for cases
> where a gateway is shared among multiple customers, each with possibly
> overlapping private numbering plans, the use of phone-context is required:
> 	sip:[e-mail];phone-context=mycarrier-customer1
>
> The use of the phone-context tag also allows interdomain private dialing,
> something impossible in todays PSTN.  For example, dialed digits for a
> particular dialing plan could be sent to a proxy for gateway lookup
>
> 	sip:[e-mail];phone-context=carrier-customer2
>
> The proxy would lookup the gateway based on dialed digits and
> phone-context.  If
> the proxy did not have gateway information for that carrier (domain), the
> request could be proxied to that domain with the Request-URI becoming:
>
> 	sip:[e-mail];phone-context=carrier-customer2
>
> These are just a few examples of the use of this tag.
>
> Are there any reasons why this tag should not be supported in SIP
> URLs in the
> next draft of RFC2543?
>
> Alan Johnston
> MCI WorldCom
>
>
>
> _______________________________________________
> SIP mailing list
> [e-mail]
> http://lists.bell-labs.com/mailman/listinfo/sip
>




_______________________________________________
SIP mailing list
[e-mail]
http://lists.bell-labs.com/mailman/listinfo/sip