[Geopriv] Location in SIP and "retransmission-allowed"

From: Rosen, Brian ^lt;Brian.Rosen@neustar.biz>
Date: Tue May 01 2007 - 13:08:03 EDT

In finishing off sip-location-conveyance we have been discussing the
"retransmission-allowed" parameter.

RFC4119 says:
'retransmission-allowed': When the value of this element is 'no', the
      Recipient of this Location Object is not permitted to share the
      enclosed Location Information, or the object as a whole, with
      other parties...

In SIP, we have two issues with this that need to be resolved.

One is that proxy servers are in the path from UAC to UAS. We have been
interpreting "retransmission-allowed=no" as a proxy may forward the
message to its next hop with location, but it may not send location
anywhere else. The UAS receiving location could not send it to any
other entity.

We have a similar problem with location based routing. As you know,
ecrit has developed a location based routing mechanism where you send a
LoST server a location and a service indicator, and you get back a URI.
An example of using this mechanism would be a call to Pizza Hut. There
could be a pizza-hut service, the UAC may send its location, a proxy
server may consult LoST to route the call to the appropriate restaurant,
and the restaurant may receive the location to use to deliver the pizza.
The UAC would like to set retransmission-allowed=no, so that Pizza Hut
could not send location to anyone else. However, having set it to "no",
would that prevent the proxy from sending it to the LoST server? Please
note that when the location is sent to LoST, no identity information is
included; just the Location Information.

In the current (-07) version of -conveyance, we have assumed that the
proxies are permitted to send location to next hop even if
retransmission-allowed=no. In the current version of -conveyance, we
have proposed a new tag for PIDF "routing-query-allowed" to specifically
cover the proxy sending location. In a review of the conveyance
document, the requirement for the latter was questioned.

So, I would like to get consensus of geopriv on the following questions:
1. Does the current definition of retransmission-allowed=no permit a sip
proxy server from sending location it receives from the UA to its next
hop?

2. Does the -conveyance document just say that, or does it need to
normatively update 4119?

3. Does the current definition of retransmission-allowed=no permit a sip
proxy server to send Location Information to a LoST server (without
identity)?

4. If the answer to 3 is yes, does -conveyance document just say that,
or does it need to normatively update 4119

5. If the answer to 4 is no, is the suggested "routing-query-allowed" as
a normative update to 4119 an appropriate way to permit the LoST query?

Brian

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Received on Tue, 1 May 2007 13:08:03 -0400

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