RFC Errata


Errata Search

 
Source of RFC  
Summary Table Full Records

RFC 4028, "Session Timers in the Session Initiation Protocol (SIP)", April 2005

Source of RFC: sip (rai)

Errata ID: 1687
Status: Held for Document Update
Type: Technical

Reported By: Radha krishna Saragadam
Date Reported: 2009-02-19
Held for Document Update by: Robert Sparks

Section 9 says:

The UAS MUST NOT increase the value of the Session-Expires header field.

It should say:

same as session 8.1
   If the request doesn't indicate support for the session timer but
   contains a session interval that is too small, the UAS cannot
   usefully reject the request, as this would result in a call failure.
   Rather, the UAS SHOULD insert a Min-SE header field containing its
   minimum interval.  If a Min-SE header field is already present, the
   UAS SHOULD increase (but MUST NOT decrease) the value to its
   minimum interval.  The UAS MUST then increase the Session-Expires
   header field value to be equal to the value in the Min-SE header
   field

Notes:

----- Forwarded Message ----
From: Radha krishna <krishna_srk2003@yahoo.com>
To: Brett Tate <brett@broadsoft.com>; "sip-implementors@lists.cs.columbia.edu" <sip-implementors@lists.cs.columbia.edu>
Sent: Thursday, February 19, 2009 10:56:31 AM
Subject: Re: [Sip-implementors] Sending 422

Thanks Brett,

So I think same should be added for UAS

<Snip from RFC section 8.1>

If the request doesn't indicate support for the session timer but

contains a session interval that is too small, the proxy cannot
usefully
reject the request, as this would result in a call failure.
Rather, the
proxy SHOULD insert a Min-SE header field containing its
minimum
interval. If a Min-SE header field is already present, the
proxy SHOULD
increase (but MUST NOT decrease) the value to its
minimum interval. The
proxy MUST then increase the Session-Expires
header field value to be equal to the value in the
Min-SE header
field, as described above.
</Snip from RFC>


Regards
S.Radha krishna




________________________________
From: Brett Tate <brett@broadsoft.com>
To: Radha krishna <krishna_srk2003@yahoo.com>; "sip-implementors@lists.cs.columbia.edu" <sip-implementors@lists.cs.columbia.edu>
Sent: Wednesday, February 18, 2009 6:42:31 PM
Subject: RE: [Sip-implementors] Sending 422

It looks like Section 9 may have forgotten to indicate the behavior when UAC timer support not indicated. Section 8.1 allows a proxy to increase the Session-Expires; I see no reason why the same cannot be done by the UAS.

> -----Original Message-----
> From: sip-implementors-bounces@lists.cs.columbia.edu [mailto:sip-
> implementors-bounces@lists.cs.columbia.edu] On Behalf Of Radha krishna
> Sent: Tuesday, February 17, 2009 9:48 PM
> To: sip-implementors@lists.cs.columbia.edu
> Subject: [Sip-implementors] Sending 422
>
> Hi
>
> Consider the following topology
> UA1 ----- Call-stateful-proxy ------ UA2
>
> UA1 does not support session timer, Make a call to UA2. Call-
> stateful-proxy adds Session-Expires:100 header and forwards to UA2. UA2
> minimum session expires is 900. But in this case INVITE will not contain
> "support: timer". According section 9, UAS can reject with 422 only if
> there is a timer tag in supported header
>
> <Snip from RFC>
>
> If an incoming request contains a Supported header field with a value
> 'timer' and a Session Expires header field, the UAS MAY reject the
> INVITE request with a 422 (Session Interval Too Small) response if
> the session interval in the Session-Expires header field is smaller
> than the minimum interval defined by the UAS' local policy. When
> sending the 422 response, the UAS MUST include a Min-SE header field
> with the value of its minimum interval. This minimum interval MUST
> NOT be lower than 90 seconds.
> </Snip from RFC>
>
> Also UAS cannot increase the session expires duration
> <Snip from RFC>
> The UAS MUST
> NOT increase the value of the Session-Expires header field.
> </Snip from RFC>
>
> What should be the behavior of UAS here?
> 1) accept the call with 100 seconds?
> 2) Increase the duration to 900 seconds while sending 200 Ok?
> Note: Session timer should not be turned-off
>
> Regards
> S.Radha krishna
>
>
>
>
> _______________________________________________
> Sip-implementors mailing list
> Sip-implementors@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors




_______________________________________________
Sip-implementors mailing list
Sip-implementors@lists.cs.columbia.edu
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors

Report New Errata