Hi Christian,

Have you seen Jonathan Rosenberg's "ICE" proposal which we discussed in SIPPING? How do you think these would relate.

thanks,
-rohan


On Monday, March 17, 2003, at 09:17 PM, Christian Stredicke wrote:


Hello again,

while we have now loose routers and strict routers it seems that a new
type occurs on the horizon: The "no router"!

This is for example the case when using NAT forwarding (e.g. with STUN
or UPnP). The router is not at all aware of SIP and does not manipulate
the packet at all. However, the router is too dumb to forward a packet
if it is coming from the wrong direction. This is the case with most of
the DSL routers today.

May I propose to use a ";nr" flag in a URI to indicate that the router
does not do any SIP changing at all?

User Agents that are able to deal with "no routers" would then register
with the following packet:

REGISTER sip:bla.com SIP/2.0
Path: <sip:62.12.245.32:54456;nr=1>
Contact: <sip:[EMAIL PROTECTED]:5060>
...

When it receives a message this could look like this:

INVITE sip:62.12.245.32:54456;nr=1 SIP/2.0
Route: <sip:[EMAIL PROTECTED]:5060>
...

SIP/2.0 200 Wonderful
Record-Route: <sip:62.12.245.32:54456;nr=1>
Contact: <sip:[EMAIL PROTECTED]:5060>
...

The nr parameter could easily indicate that the previous router did not
change the packet at all and that the next entity has to fix this before
processing the message. Alternatively, the router sending the packet
could fix the route before sending it.


What do you think? Is this really necessary? Just omit the nr parameter
and conclude implicitly? How else should we deal with routers that are
not SIP-aware? I don’t like the route encoding in the header
(sip:abc?route=def) as it raises many questions about how to merge this
with other existing routes.

Unfortunately, omitting the private address is no solution, as devices
in the same subnet have to bypass the "no router". Many DSL routers are
not able to send packets from private address via the public address to
the other private address.

Cheers,


Christian -- Dr. Christian Stredicke sip:[EMAIL PROTECTED]



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