Subject: RE: [Sipping] Device Identity

From: "Jean-Francois Mule" <[email-masked]>
Date: Fri, 17 Feb 2006 09:48:09 -0700

Josh Littlefield wrote:
> Right, and sipping-config-framework allows exactly this form or UUID
> URI/URN as well.  The benefit of the purely MAC-based form specified
> there:
> 
> 	sip:[email-masked]
> 
> is that it IS predictable for hard clients when only the MAC address
> is
> written on the box.  I'm also aware of a situation where certificate
> based authentication, using existing certificates that validate a MAC
> address, could leverage this nicely.  No way to apply those
> certificates
> to a UUID that factors in an unknown time value.

Looking at this thread, I wonder what the use cases are for having a
layer-2 device identifier or interface identifier represented as a
'device identity' in the SIP signaling or worse in the host part of the
SIP URI.

A couple of questions and comments:
 - re: GRUU, isn't there is a one-to-many relationship between a device
and a GRUU? (if you can run multiple UA instances on one physical
device);
 - having a MAC address in the host part of a URI makes me wonder what
implications this may have on privacy (some folks are worried about an
IPv6 address obtained using SAAC using a fixed interface ID - rfc 3041).
Is it ok to use a MAC in the host part of a sip URI?
 - may be these kinds of parameters should be handled as part of opaque
parameter fields and we could have some more generic values. A registry
may be good to point to as Dean mentioned. Tying this kind of parameter
value with a DHCP option the device may receive may also be of interest
for some. For example, the remote-id in DHCPv4 RFC3046 or in its little
brother in the current DHCPv6 I-D may refer to an interface
identifier... It is usually insert by a dhcp relay agent but if a UA
could simply put whatever option value it receives as its device
identifier, it could help create device identifiers that differ from MAC
addresses. 

Jean-Francois
[email-masked]

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---

From: Paul Kyzivat <[email-masked]>
Date: Fri, 17 Feb 2006 14:00:15 -0500

> and a GRUU? (if you can run multiple UA instances on one physical

That is why gruu calls for an *instance* id, not a device id. It is an 
instance of a UA, loosely defined to give lattitude for the many 
different form factors that UAs may take on.

> Is it ok to use a MAC in the host part of a sip URI?

Well, there are always tradeoffs. The point of using a MAC is that it is 
something that a device can have without any special provisioning. It is 
helpful when you want to bootstrap the provisioning. Of course this does 
result in giving up some privacy. If you don't like that, then some 
other form of identifier should be used, and it needs to find its way 
into the device by other means. This is exactly what will have to happen 
for softphones, but it can apply to other "devices" as well.

This may all be off track from the original question in this thread. As 
I recall, it was about whether a device id was available. Then we got 
off in the woods about various kinds of ids already in use that might be 
reused. Lots of people express a desire for some kind of id, often 
described as a device id, but I don't think the expected attributes are 
as consistent as the name.

	Paul