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RE: [Sip] GRUU and Grid alternative
I'd like to point one thing out from the annals of the way-back
machine...
At IETF-59 in Seoul, I made a presentation, which I recall being well
received by at least a few folks (I believe Cullen was one of them) in
which a separate, but related problem space to GRUU was being discussed:
the GUID.
The draft has expired long ago
(http://mirrors.isc.org/pub/www.watersprings.org/pub/id/draft-stucker-si
p-guid-00.txt) but the introduction captures the problem space fairly
succintly:
---
Within SIP, there arise situations where it is necessary to ensure
that an action is applied to a particular user agent (UA)
instance,
but the existing mechanisms within SIP are not always reliable.
For
example, although registrations identify a routable address and
port
of a particular UA, in an environment that uses dynamically
assigned
IP addresses (NATs, VPNs, short-lease DHCP networks) there is no
ready way of always tying registrations together across time for a
particular UA instance. In these environments, the usual IP/port
combination that defines a particular routing location of a UA is
unreliable over time as an identifier of that UA.
As a result, an identifier that UAs can use as a "finger-printing"
mechanism to identify themselves is useful. Whereas the Globally
Routable UA URIs (GRUU) draft [4] seeks to address a
server-generated
identifier for the UA, this draft seeks to define a
client-generated
approach to a similar problem.
The mechanism defined in this document allows a particular UA
instance to construct a globally unique identifier which can be
used
by SIP services to process requests that require, or are enhanced
by,
the ability to identify a particular UA instance in the network
over
a long period of time.
---
This notion was folded into the GRUU draft as a property of the grid
parameter (ie. the grid could be used as a GUID).
If we're to remove the grid from gruu, I think we still want to maintain
this property of the grid: it's still very useful.
Regards,
Brian
> -----Original Message-----
> From: Dean Willis [mailto:dean.willis at softarmor.com]
> Sent: Tuesday, October 03, 2006 11:17 PM
> To: Jonathan Rosenberg
> Cc: IETF SIP List
> Subject: Re: [Sip] GRUU and Grid alternative
>
> Jonathan Rosenberg wrote:
>
> > The basic idea would be to remove the grid mechanism
> entirely from the
> > gruu draft. Instead, a separate specification would be
> developed which
> > would allow for loose routing to apply to user agents. So,
> consider a
> > UA which registers. It would include a contact and a
> Supported header
> > field with the value "ua-route". The registrar, assuming it
> > understands this, notes that the UA supports UA loose routing and
> > stores the contact. When an incoming call arrives for the
> AOR, rather
> > than rewriting the R-URI with the registered contact, it pushes the
> > registered contact into a Route header and leaves the R-URI alone
> > (assuming the registered UA supports this mechanism).
>
> I'd like to go on record as saying that this apparently
> resolves one of the Great Fundamental Evils of SIP that I've
> so often sermonized and thereby either makes me happy and
> fulfilled or leaves me looking for something else to whine
> about. In either case, it is a very good fix, and long overdue.
>
> --
> Dean
>
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Use sipping at ietf.org for new developments on the application of sip