Subject: [MMUSIC] Re: Comment on TCP ICE

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 04 Jan 2007 14:02:44 -0500

Sorry for the long delay in responding to all of these. I am finally 
getting back to work on this after a work-based hiatus.

inline.

Gonzalo Camarillo wrote:

> Hi,
> 
> the TCP ICE spec changes the way TCP connection reestablishment works in
> RFC 4145. RFC 4145 allows applications to close a TCP connection without
> requiring a new offer/answer exchange. However, a new offer/answer
> exchange is required to reestablish (i.e., repair) a connection.
> 
> TCP ICE, on the other hand, requires a new offer/answer exchange to
> close a TCP connection, but does not require it to repair a connection.

It is not the intent that a new exchange is required to close a 
connection. The intention is that once a connection is up and in use for 
media, it will stay up and should not normally be closed. However, if 
the client needs to close it, or it closes due to some temporary glitch, 
thats fine - no new o/a exchange is needed to reopen one. The only case 
in which you would normally close a connection is when a media stream 
ends, which does require a new O/A exchange.

> 
> The ICE TCP spec says:
> 
>   "Unlike RFC 4145, additional signaling is not required to repair a
>    closed connection."
> 
> I believe that the ICE TCP spec needs to give a slightly longer
> explanation about it so that implementers understand both differences.
> Maybe an extra paragraph along the lines of this email.

I think clearly explanation is needed. If the above sounds OK to you, I 
will add text clarifying that.

-Jonathan R.

-- 
Jonathan D. Rosenberg, Ph.D.                   600 Lanidex Plaza
Cisco Fellow                                   Parsippany, NJ 07054-2711
Cisco Systems
[email-masked]                              FAX:   (973) 952-5050
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---

From: Gonzalo Camarillo <[email-masked]>
Date: Sun, 21 Jan 2007 10:44:37 +0200

Hi Jonathan,

yes, please, go ahead add text clarifying the issue. The thing is that 
some sessions actually have media streams that end way before the 
session (e.g., a file transfer). We need to be clear on what to do if 
one needs to terminate a, say, TCP connection in the middle of a session 
and is using ICE.

Cheers,

Gonzalo

---

From: Paul Kyzivat <[email-masked]>
Date: Tue, 23 Jan 2007 11:11:40 -0500

What are the implications here? How are the cases to be distinguished: 
closed because no longer needed so reopen not desired, vs closed 
inadvertently and reopen desired.

Its no problem if both ends agree on the intent. But if they don't agree 
then there are small issues. For one side it is a matter of whether to 
attempt to reopen or not, and for the other side it is whether to be 
listening or not. Presumably things won't be too awful if they disagree 
- no connection will be reestablished. But one side or the other will be 
doing work that is wasted.

Do we just leave it to the application to know whether reopening is 
appropriate?

	Paul

Gonzalo Camarillo wrote:
>> connection. The intention is that once a connection is up and in use 
>> for media, it will stay up and should not normally be closed. However, 
>> if the client needs to close it, or it closes due to some temporary 
>> glitch, thats fine - no new o/a exchange is needed to reopen one. The 
>> only case in which you would normally close a connection is when a 
>> media stream ends, which does require a new O/A exchange.
>>
>>
>>>
>>> The ICE TCP spec says:
>>>
>> I think clearly explanation is needed. If the above sounds OK to you, 
>> I will add text clarifying that.
>>
>> -Jonathan R.
>>
> 
>