Subject: [MMUSIC] I-D Action: draft-ietf-mmusic-sdp-cs-11.txt

From: [email-masked]
Date: Mon, 14 May 2012 02:42:26 -0700

A New Internet-Draft is available from the on-line Internet-Drafts directories. This draft is a work item of the Multiparty Multimedia Session Control Working Group of the IETF.

	Title           : Session Description Protocol (SDP) Extension For Setting Up Audio and Video Media Streams Over Circuit-Switched Bearers In The Public Switched Telephone Network (PSTN)
	Author(s)       : Miguel A. Garcia-Martin
                          Simo Veikkolainen
	Filename        : draft-ietf-mmusic-sdp-cs-11.txt
	Pages           : 35
	Date            : 2012-05-14

   This memo describes use cases, requirements, and protocol extensions
   for using the Session Description Protocol (SDP) Offer/Answer model
   for establishing audio and video media streams over circuit-switched
   bearers in the Public Switched Telephone Network (PSTN).

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sdp-cs-11.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

This Internet-Draft can be retrieved at:
ftp://ftp.ietf.org/internet-drafts/draft-ietf-mmusic-sdp-cs-11.txt

The IETF datatracker page for this Internet-Draft is:
https://datatracker.ietf.org/doc/draft-ietf-mmusic-sdp-cs/

---

From: "Miguel A. Garcia" <[email-masked]>
Date: Mon, 14 May 2012 15:04:12 +0200

Hi:

We have just submitted version 11 of the SDP CS draft. The main change 
was to align the representation of the User-to-User Information Element 
with that used in the User-to-User header field in SIP. This addresses 
Paul's comment.

 From the authors' perspective, the draft is ready for entering WGLC.

BR,

        Miguel

On 14/05/2012 11:42, [email-masked] wrote:
> _______________________________________________
> mmusic mailing list
> [email-masked]
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>
>

-- 
Miguel A. Garcia
+34-91-339-3608
Ericsson Spain

---

From: Paul Kyzivat <[email-masked]>
Date: Mon, 14 May 2012 11:07:49 -0400

> with that used in the User-to-User header field in SIP. This addresses

Thanks. It does address my comment.

I've just little stuff now:

In section 5.2.3.3: The following:
    start with the the value starting at the Protocol Discriminator octet

contains "the the" and is otherwise awkward. How about:
    start with the Protocol Discriminator octet

Section 5.2.3.3 also requires an even number of hex digits, but the ABNF 
doesn't. That is also true in the cuss draft, but there the ABNF doesn't 
explicitly address hex. You have the opportunity to specify an even 
number of digits in the ABNF. Also, I note that the existing ABNF uses 
HEXDIG from 5234 incorrectly in that it assumes it only covers A-F, when 
it also already includes 0-9 and A-F. So how about:

uuie-value = 1*65(HEXDIG HEXDIG)	
              ;0-9, A-F, and a-f	
              ;HEXDIG defined in RFC5234	

	Thanks,
	Paul

>> A New Internet-Draft is available from the on-line Internet-Drafts
>> directories. This draft is a work item of the Multiparty Multimedia
>> Session Control Working Group of the IETF.
>>
>> Title : Session Description Protocol (SDP) Extension For Setting Up
>> Audio and Video Media Streams Over Circuit-Switched Bearers In The
>> Public Switched Telephone Network (PSTN)

---

From: "Miguel A. Garcia" <[email-masked]>
Date: Mon, 21 May 2012 15:54:50 +0200

Hi Paul,

Thanks for your comments. I think I forgot to reply to this e-mail. See 
my answers inline.

>      start with the Protocol Discriminator octet

of course. We will fix it as per your suggestion.

>                ;HEXDIG defined in RFC5234	

I agree with your proposal of making it an even number in ABNF.

With respect lack of lowercase letter a-f, (remember that HEXDIG only 
allows digits 0-9 and uppercase letters A-F, I don't mind your proposal 
of only allowing uppercase A-F. However, I will draw your attention that 
the cuss draft does allow both lowercase and uppercase. If we want to 
have the same syntax, both drafts should go for the same proposal.

BR,

     Miguel

-- 
Miguel A. Garcia
+34-91-339-3608
Ericsson Spain

---

From: Paul Kyzivat <[email-masked]>
Date: Mon, 21 May 2012 10:10:42 -0400

> have the same syntax, both drafts should go for the same proposal.

According to 5234:

          DIGIT          =  %x30-39
                                 ; 0-9
          HEXDIG         =  DIGIT / "A" / "B" / "C" / "D" / "E" / "F"
and
    Literal text strings are interpreted as a concatenated set of
    printable characters.

    NOTE:

       ABNF strings are case insensitive and the character set for these
       strings is US-ASCII.

    Hence:

          rulename = "abc"

    and:

          rulename = "aBc"

    will match "abc", "Abc", "aBc", "abC", "ABc", "aBC", "AbC", and
    "ABC".

So HEXDIG already allows A-F and a-f.

	Thanks,
	Paul

---

From: Tom Taylor <[email-masked]>
Date: Mon, 21 May 2012 10:36:13 -0400

I'm afraid I don't agree with your interpretation, Paul. The condition 
"ABNF strings are case insensitive and the character set for these 
strings is US-ASCII" connotes the following to me:

RUlename = "abc"
and
ruleNAME = "abc"

are the same thing, but

rulename = "abc"
and
rulename = "ABC"

are different.

> So HEXDIG already allows A-F and a-f.
...

---

From: Paul Kyzivat <[email-masked]>
Date: Mon, 21 May 2012 10:47:30 -0400

Tom,

> strings is US-ASCII" connotes the following to me:

I quoted the relevant sections of 5234 that cause your two last lines 
above to be equal. See further below...

>> will match "abc", "Abc", "aBc", "abC", "ABc", "aBC", "AbC", and

up to an including the example above.

	Thanks,
	Paul

---

From: Tom Taylor <[email-masked]>
Date: Mon, 21 May 2012 11:29:55 -0400

Ack.

...
...

---

From: "Miguel A. Garcia" <[email-masked]>
Date: Tue, 22 May 2012 09:06:42 +0200

Ahh,

good point regarding the case insensitivity of strings in RFC 5234.

Then, I am fine with your comment.

/Miguel

-- 
Miguel A. Garcia
+34-91-339-3608
Ericsson Spain

---

From: "Miguel A. Garcia" <[email-masked]>
Date: Tue, 22 May 2012 09:07:37 +0200

Ok, I think we all agree. Next version of the draft will be edited 
accordingly.

/Miguel

-- 
Miguel A. Garcia
+34-91-339-3608
Ericsson Spain