[SIPForum-discussion] LPN and SIP

Thu Jul 28 05:39:29 UTC 2005

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
>>
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>>
> 
> 
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