Re: [Sip] PING/PONG

[Robert Sparks <[e-mail]>]

I hope we're talking past each other at this point.

You seem to be proposing that I would _never_ open a connection with 
anything but
one proxy, even if I had network visibility to something else and the 
knowledge that
I wanted to talk to it.

I'm saying that if I want to have a dialog with something that I can 
reach (but it can't
open a connection to me), that I want to open a connection to it and 
for the duration
of that dialog, keep the connection alive. My original point is that I 
want to use the
same mechanism we define for keeping a connection to a proxy alive.

I think maybe you're only seeing the "tried to place a call and it 
ended up on some
random voicemail server" use case in your response below. Look at it 
from a
retrieving voicemail point of view. Then consider other services (like 
a presence server)
I might like to use, perhaps from a third party provider.

RjS


On Dec 3, 2004, at 9:57 PM, Jonathan Rosenberg wrote:

> inline.
>
> Robert Sparks wrote:
>
>>>
>>>> Endpoints behind the things we are wanting to do this refresh 
>>>> things to can be signaling
>>>> directly with endpoints that aren't (a service provider could let 
>>>> people talk to voice-mail
>>>> or conference servers directly).
>>>
>>>
>>> I don't see how that practically works in the presence of nat. If 
>>> you are using tcp/tls, the thing to which you have a connection open 
>>> is the only place from which you can get subsequent requests. Thus, 
>>> if I make a call that lands on a voicemail server, the proxy holding 
>>> my tcp/tls connection has to be on the signaling path, or it just 
>>> won't work.
>> If I can establish a tcp/tls connection to that voicemail server, 
>> then subsequent requests from it can
>> come back down that connection assuming we can keep it alive.
>
> My point is, there may not (indeed, won't be) a connection to that 
> thing in the first place. It would need to be established only after 
> the call setup is complete. How would the client know to do that? You 
> also have a race condition, whereby even if the client knew to do 
> this, a sip request could arrive from the voicemail server before the 
> client can establish the connection. I'm just not seeing the benefit 
> here.
>
> -Jonathan R.
>
>
> -- 
> Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
> Director, Service Provider VoIP Architecture   Parsippany, NJ 
> 07054-2711
> Cisco Systems
> [e-mail]                              FAX:   [phone]
> http://www.jdrosen.net                         PHONE: [phone]
> http://www.cisco.com


_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use [e-mail] for questions on current sip
Use [e-mail] for new developments on the application of sip