[SIPForum-discussion] LPN and SIP

Fri Jul 29 19:09:41 UTC 2005

Steve,

I don't have any first-hand experience with a residential VoIP
providers, so I may have some incorrect assumptions.

Would a service provider identify me based on the phone number from the
other network, or would I have a unique identity within the network?  I
assumed I would have a native address, and that a call that originates
on the IP network would not have to submit my PSTN phone number as an
address.  

On the other hand, phone numbers will never go away.  Phones don't have
keyboards, whether IP based or not.  So, it may be that people will
choose not to publish their native IP network address - it just
complicates things, for no apparent reason.   Routing by number will
work in either network.

We are destined to be known by a number rather than a name, aren't we?
;-)

-Rick

  _____  

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Carr, Steve
Sent: Friday, July 29, 2005 1:22 PM
To: 'An open list for discussion of SIP-related topics'
Subject: RE: [SIPForum-discussion] LPN and SIP

Maybe I'm confused, but, is this really a valid real world example????.

As far as I know, Vonage and CallVantage and several others use NANP
phone numbers, and issue SIP (or MGCP) CPE to their customers (or they
buy them at Circuit City). The end user connects his black phone to the
CPE and away they go dialing phone numbers, not SIP URIs. In addition,
incoming calls from PSTN users are possible because the VoIP subscriber
has a valid number that can be dialled from any PSTN or PLMN device.

I'm guessing that Vonage does not get NANP numbers by getting its own
Area Code, but instead gets blocks of numbers from the LEC, and uses LNP
to redirect incoming calls to their gateways. They also offer virtual
phone numbers so that their customer can give out local numbers to
friends and family so that they can make local calls that are free from
PSTN to VoIP user.

Therefore, to port from one VoIP service provider to another involves
modifying the LNP database, and also ENUM could be used to provide an
equivalent for VoIP originated calls (to avoid LNP dip costs).

Steve.

  _____  

From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Jay Batson
Sent: Wednesday, July 27, 2005 11:50 PM
To: An open list for discussion of SIP-related topics
Subject: Re: [SIPForum-discussion] LPN and SIP

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

Then, let's presume Joe moves providers to, say, Verizon where his new
URI would be:
   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.
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), I must maintain my business relationship
with Earthlink.  When I terminate that relationship, the URI
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).

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
+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 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, then moves
his service to 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' 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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