Subject: [MEDIACTRL] Comments on draft-ietf-mediactrl-sip-control-framework-01.txt

From: "McGlashan, Scott" <[email-masked]>
Date: Thu, 28 Feb 2008 12:24:10 +0000

A couple of little issues:

[1] Can we clarify the behavior in the case that a REPORT message is sent from the Server, but no 200 response is sent back by the client. Is there a timeout for receiving the 200 response? Should the Server re-transmit the REPORT (same Seq value) and if so for how many iterations/time?

[2] ABNF: Content-Type is not defined as a header but something which occurs after the header block and before the content data. If I want to send a payload in CONTROL (same issue applies to responses), then according to the ABNF the format would look like this (comments in []):

SCFW transactionid1 CONTROL <CRLF>
Control-Package: XXX <CRLF>
Content-Length: XXX <CRLF>
<CRLF>                  [according to control-request]
Content-Type: XXX       [following lines according to control-content]
<CRLF><CRLF>
.. Data ...
<CRLF>

This is different from the examples, e.g. (6) in 10. Examples:

SCFW i387yeiqyiq CONTROL
Control-Package: <package-name>
Content-Type: example_content/example_content
Content-Length: 11

<XML BLOB/>

I think the example is correct: no extra <CRLF> between the headers and Content-Type.

This can be fixed by

(a) Adding Content-Type as a member of headers.

(b) Changing control-content to

control-content = data CRLF

With this change, we would match the examples (and I think the intent of spec) and still have a clear mechanism for terminating the PDU.

(a) headers, no content

SCFW transactionid1 CONTROL <CRLF>
Control-Package: XXX <CRLF>
Content-Length: 0 <CRLF>
<CRLF>          [after headers according to control-request]

i.e. if there is no Content-Length header, or a Content-Length with a zero value, then content-control clause does not apply and the PDU is terminated by the <CRLF> after any headers.

(b) headers and content

SCFW transactionid1 CONTROL <CRLF>
Control-Package: XXX <CRLF>
Content-Length: XXX <CRLF>
Content-Type: XXX <CRLF>
<CRLF>          [after headers according to control-request]
.. Data ...             [following lines according to control-content]
<CRLF>

i.e. if a non-zero Content-Length header is specified somewhere in headers, then the content-control clause applies: the PDU is complete after Data of Content-Length value plus <CRLF>.

Thanks

Scott

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From: "Chris Boulton" <[email-masked]>
Date: Thu, 28 Feb 2008 13:21:01 -0000

Look good to me - I will roll them into the next version.

Chris.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of McGlashan, Scott
Sent: 28 February 2008 12:24
To: [email-masked]
Subject: [MEDIACTRL] Comments
ondraft-ietf-mediactrl-sip-control-framework-01.txt

[1] Can we clarify the behavior in the case that a REPORT message is
sent from the Server, but no 200 response is sent back by the client. Is
there a timeout for receiving the 200 response? Should the Server
re-transmit the REPORT (same Seq value) and if so for how many
iterations/time?

[2] ABNF: Content-Type is not defined as a header but something which
occurs after the header block and before the content data. If I want to
send a payload in CONTROL (same issue applies to responses), then
according to the ABNF the format would look like this (comments in []):

SCFW i387yeiqyiq CONTROL

<XML BLOB/>

I think the example is correct: no extra <CRLF> between the headers and
Content-Type.

This can be fixed by

With this change, we would match the examples (and I think the intent of
spec) and still have a clear mechanism for terminating the PDU.

(a) headers, no content

i.e. if there is no Content-Length header, or a Content-Length with a
zero value, then content-control clause does not apply and the PDU is
terminated by the <CRLF> after any headers.

(b) headers and content

i.e. if a non-zero Content-Length header is specified somewhere in
headers, then the content-control clause applies: the PDU is complete
after Data of Content-Length value plus <CRLF>.

Thanks

Scott