Subject: RE: [NSIS] Re: QoS NSLP: ACK flag has no effect?

From: "Geib, Ruediger" <[email-masked]>
Date: Fri, 24 Mar 2006 09:39:15 +0100

John,

I agree, the ACK mechanism can be removed. When I proposed it, my 
idea was to get Response messages without RII processing. 
Couldn't the Response of the QNR be triggered 
a) by default in the case of state changing Reserves
b) by a simple flag instead of the RII

I expect any application using QoS to request a confirmation of 
resource set up and state changes. There seem to be two ways to 
link QoS NSLP to e.g. SIP or RTSP:

- Use a QoS NSLP "Response" and control QoS set up on NSLP layer. 
  SIP is informedvia an API, that QoS set up is succesful. 
  This as the more generic approach, also taken by 
  RFC3312/4032 (SIP WG) and it is required to operate PCN (TSV WG).

- Use SIP itself to confirm sucessful QoS set up (i.e. no QoS NSLP 
  response) from the destination. This requires a new design for 
  each application protocol.

If the ACK mechanism is removed, also Reduced Refresh is removed. 
If Reduced Refresh is to be kept, it must be reworded.

Regards,

Rüdiger

|-----Original Message-----
|From: Roland Bless [mailto:[email-masked]]
|Sent: Thursday, March 23, 2006 5:40 PM
|To: [email-masked]
|Cc: [email-masked]; [email-masked]
|Subject: Re: [NSIS] Re: QoS NSLP: ACK flag has no effect?
|
|
|Hi John
|
|> I strongly agree with Robert on this.  I had dinner with TSV & RAI
|> ADs and was told that allowing SIP to support UDP was one of the
|> worst mistakes they made.  It seems that SIP deployments are having
|> major problems with fragmentation, for example, and people are now
|> doing creative things to try to fix it.
|> 
|> My feeling is that TCP is far from a burden for modern hosts, IMO.
|
|So a consequence would be to rule out the ACK mechanism for
|transport reliability. Good. I would then recommend to remove
|the ACK mechanism completely unless someone speaks up to keep
|it, stating the problem it should solve.

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---

From: Roland Bless <[email-masked]>
Date: Fri, 24 Mar 2006 18:14:03 +0100

Hi Ruediger,

> If Reduced Refresh is to be kept, it must be reworded.
I disagree here. Why must the reduced refresh be removed when we don't
have the ACK anymore? The only difference between a normal refresh and a 
reduced
refresh is the missing QSPEC. It's not like the summary refresh in RSVP 
which
is able to refresh several sessions with only one message. Please see also:
http://www1.ietf.org/mail-archive/web/nsis/current/msg06033.html
Sure, text must be reworded for reduced refreshed, but there is no technical
reason why dismissing the ACK causes removal of the reduced refresh.

Regards,
 Roland