[SIPForum-discussion] LPN and SIP

Thu Jul 28 07:31:42 UTC 2005

http://one.address.name has a meta service for SIP Redirect and DNS.  
The only problem is that both old and new providers must allow public  
SIP URIs in and out of their service, not all do.

Regards,
Catalin S.
http://www.eurovoice.ro

On Jul 28, 2005, at 7:39 AM, Henning Schulzrinne wrote:

> One would hope that name registrars would provide such forwarding  
> services, given that domain names are available for less than $10/year  
> and that they commonly include email-forwarding services. Thus, a  
> family or business could have their personal and permanent name for a  
> fairly modest expense. I don't think provider-based names are a good  
> long-term solution - why would I want to advertise that I'm with  
> carrier X to the world at large? (Other organizations, such as  
> colleges, might alos provide permanent names; we already provide  
> user at alum.cs.columbia.edu to our former students.)
>
> Jay Batson wrote:
>> Rick --
>> I'm not speaking on behalf of a service provider, so this is merely  
>> an informed opinion.
>> I'm going to re-state some of what you said as a base on which to add  
>> my thoughts.
>> Let's use real-company examples.  Assume our user Joe is a Vonage  
>> customer, and gets this SIP URI from Vonage:
>>    joe at vonage.com <mailto:joe at vonage.com>
>> Then, let's presume Joe moves providers to, say, Verizon where his  
>> new URI would be:
>>    joe at verizon.net <mailto:joe at verizon.net>  (for example)
>> It's rational to make the case that Vonage "owns" the LHS of the  
>> Vonage URI, based on the precedent of how it works with email (as you  
>> said.)  To explain further, assume I have an email address  
>> jay at earthlink.net <mailto:jay at earthlink.net>.  In order for me to  
>> have Earthlink continue to process my email (which might, or might  
>> not include forwarding to another account, e.g. a Gmail account named  
>> jay at gmail.com <mailto:jay at gmail.com>), I must maintain my business  
>> relationship with Earthlink.  When I terminate that relationship, the  
>> URI jay at earthlink.net <mailto:jay at earthlink.net> "goes back" to  
>> Earthlink for possible use by somebody else with the name Jay.  This  
>> would tend to suggest that a user must have a relationship with a SIP  
>> service provider in order to continue to use the LHS of the URL they  
>> get from that service provider.
>> As you said, however, SIP Redirect is a goodie we have in the SIP  
>> world that might help us through the shortcomings of email.  Using  
>> the illustration above, Vonage could choose to let you set a SIP  
>> "forwarding" option.  On receipt on an INVITE to your account at  
>> Vonage, their SIP server could send back a Redirect to your  
>> configured forwarding target (e.g. jay at verizon.net  
>> <mailto:jay at verizon.net>).
>> While this mechanism exists in the protocol design, the key is that  
>> Vonage must choose to provide this, along with setting the terms on  
>> which they might offer it.  E.g. they might want you to remain a  
>> full-paying Vonage subscriber in order to get them to send a  
>> redirect.  (They could, of course, also just invent an offering that  
>> costs a mere couple of bucks a year that will *only* sends a redirect  
>> for any INVITE received at Joe's "old" address.)
>> The way around this might be to take this last bit one step farther.   
>> If there were a service provider who offered a global "Redirect  
>> service," we might have a way out.  Presume this service can provide  
>> you a "SIP URI for life," that you then give to people as "your" SIP  
>> URI.  All your INVITEs go here, but this service provider exists  
>> solely to issue a Redirect to your "actual" (configured) SIP service  
>> provider of the moment.  (Note that this clever provider probably  
>> still "owns" the LHS of the URI-for-life that you get from them; it's  
>> just that they have a service that supplies "portability" to  
>> providers that actually set up calls.)  Voila - I get the same  
>> *effect* that "URI portability" would provide.
>> The counter precedent, of course, is the PSTN LNP experience, where  
>> the consumer has some ownership of their number.  Which is what you  
>> were looking for, I suspect.  Tough to say whether the email  
>> experience, or the PSTN LNP experience is the better precedent.  But  
>> at the moment, the email experience rules probably prevail.  And  
>> IMHO, I like it this way, since it provides for more business  
>> opportunities.
>> But SIP doesn't necessarily dictate these rules; the Redirect  
>> mechanism would seem to enable the movement of users, and that's all  
>> the protocol needs to do.  From there, it's up to clever businesses  
>> to figure out how to meet the desires of users.
>> Again, these are merely my humble thoughts.
>> -jb
>> -------
>> Jay Batson
>> batsonjay at sipforum.org <mailto:batsonjay at sipforum.org>
>> +1-978-824-0111
>> On Jul 27, 2005, at 6:28 PM, Ringel, Rick wrote:
>>>
>>> Hello group,
>>>
>>> I'm doing homework relating to Interconnect issues, and looking at  
>>> user mobility.   I have a question regarding mobility between  
>>> service providers.
>>>
>>> On the PSTN, number portability is a big issue, and thru regulatory  
>>> activity, this is being addressed in the circuit network.
>>>
>>> In a SIP network, the issue takes on a different nature.  Clearly,  
>>> as an endpoint behind an IP-PBX, the user's identity is owned by the  
>>> domain owner.  If Joe leaves Acme, he has to leave his joe at acme.com  
>>> <mailto:joe at acme.com> identity behind.  No problems here.
>>>
>>> However, in residential services, a user wants to create and publish  
>>> an identity that they own, independent of any particular service  
>>> provider.   If Joe publishes his address as joe at provider.net  
>>> <mailto:joe at provider.net>, then moves his service to  
>>> joe at competitor.net <mailto:joe at competitor.net>, by LNP thinking,  
>>> either the owner of provider.net would have to redirect Joe's calls  
>>> to competitor.net, or the full address 'joe at provider.net  
>>> <mailto:joe at provider.net>' would undergo a translation (DNS?) prior  
>>> to delivery at provider.net's service point.  Alternatively, Joe  
>>> could obtain his own domain name and point a DNS record to his  
>>> service provider, but that doesn't seem scalable.  I haven't found a  
>>> solution that appears satisfactory.
>>>
>>> In my view, the service provider and the domain name should not be  
>>> equated.  The same issue exists for e-mail services, but nobody  
>>> expects their e-mail account to be portable (yet).  I think it is  
>>> probable that expectations for IP phone service will be different,  
>>> and that eventually, SIP URI portability will become an issue.
>>> Does anybody know of any IETF tasks, public documents, or  
>>> discussions on this topic?  I've found lots of info on LPN relating  
>>> to TEL: URIs, but I have yet to see anything that addresses the  
>>> problem when users are addressed by a <username>@<domain> format.
>>>
>>> -Rick Ringel
>>>
>>> _______________________________________________
>>> discussion mailing list
>>> discussion at sipforum.org <mailto:discussion at sipforum.org>
>>> http://sipforum.org/mailman/listinfo/discussion
>>>
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