Subject: [SIP] RE: [Simple] Difference between a SUBSCRIBE and a re-SUBSCRIBE

From: Robert Sparks <[email-masked]>
Date: Tue, 29 May 2001 10:10:51 -0400

You are correct that a receiving agent can only expect
increasing CSeqs due to the opportunity for intervening
proxies to consume messages (with a 407 for example).

The remaining motivation for increasing by 1 on the sending
side, as I understand it, is preserving CSeq space.

RjS

> -----Original Message-----
> From: Christian Jansson [mailto:[email-masked]]
> Sent: Monday, May 28, 2001 7:59 AM
> To: David Simons; Jonathan Rosenberg
> Cc: [email-masked]
> Subject: Re: [Simple] Difference between a SUBSCRIBE and a 
> re-SUBSCRIBE
> 
> 
> 
> > This doesn't strictly follow
> > RFC2543 because the SUBSCRIBE CSeq wouldn't be contiguous.  
> But, it does
> > keep the CSeq counts up-to-date.
> >David J. Simons
> 
> This requirement about contiguous CSeqs, is it really 
> necessary? Is it valid
> at all? For example if there is one or more proxy servers 
> that requires
> Proxy-Authentication some CSeqs may be used for resending 
> request with valid
> credentials. So, a UAS should never expect to receive 
> contiguous CSeqs. But,
> it should expect to receive strictly monotonically increasing 
> CSeqs. And if
> this is the case, why do we put the requirement on the UAC to 
> send with
> contiguous CSeqs. I think the requirement should be changed 
> to: "send with
> strictly monotonically increasing CSeqs".
> 
> Christian Jansson
> Hotsip
> www.hotsip.com
> 
> 
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> 

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