Subject: [Sip] more BNF issues

From: Rohan Mahy <[email-masked]>
Date: Sun, 3 Feb 2002 15:48:16 -0800 (Pacific Standard Time)

Hi,

In addition to some of the issues that Bill Fenner caught....

- AuthenticationInfo should use HCOLON instead of COLON

- qvalue is defined twice (Accept-Encoding and Contact)

- Via is really screwed  a) there is currently no space of any kind
between sent-protocol and sent-by:

	Via: SIP/2.0/UDPhost.domain.com

should this be a single SP, HWS, or LWS?

b) I don't think we want any space between sent-protocol and sent-by.  I
would use "/" instead of SLASH here..  I would redefine sent-protocol as
follows:

	sent-protocol = SIP-Version "/" transport

and delete protocol name and protocol version to be consistent with the
start-line.

- I propose a new HWS (horizontal white space) label

HWS = ( SP | HT )
LWS = *HWS [CRLF] 1*HWS
SWS = *HWS [CRLF  1*HWS]

i think this makes the intent more obvious

- option-tag should move down near Require

- to make Contact consistent with Caller Preferences, STAR needs to
migrate into the contact-param line:

Contact = ("Contact" | "m") HCOLON contact-param *(COMMA contact-param)
contact-param = (STAR | name-addr | addr-spec) *(SEMI contact-params)

- the definition of "credentials" (Authorization header in line 5833) also
needs to have LWS between "Digest" and the params.

- general comment.  using <'> instead of "'" would be more readable IMO

- the precedence of disposition-param if ambiguous.  propose:

Content-Disposition = "Content-Disposition" HCOLON disposition-type
   *( SEMI  ( disposition-param | generic-param ) )

disposition-param = "handling" EQUAL ("optional" | "required" |
  other-handling)

- similar issue with retry-param

- Accept and Content Language should use "-" instead of MINUS

- i imagine rfc1123-date should be:

	= wkday "," SP date1 SP time SP "GMT"

- in the definition of digest-chlng the "optional" brackets [] are
redundant

- qop-options  is COMMA apropos or should it be "," SP or "," HWS

- Timestamp header.  i've never seen one really used, and the only example
gives no mention of the second "delay" token.  is this an error?

ok,  more later?

thanks,
-rohan

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---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 04 Feb 2002 00:08:48 -0500

> - AuthenticationInfo should use HCOLON instead of COLON

Fixed.

> - qvalue is defined twice (Accept-Encoding and Contact)

I've already fixed that one, thanks.

> should this be a single SP, HWS, or LWS?

LWS. I already fixed that one.

> and delete protocol name and protocol version to be consistent with the

I don't feel strongly here, but am inclined to keep the current
definition, as this is what has been specified in rfc2543, although with
implicit LWS. Why remove it here and not other places?

> - I propose a new HWS (horizontal white space) label

Since we are using RFC2234, it defines WSP for us as your HWS. THen, we
have copied the rfc2822 version of LWS, and defined SWS as [LWS]. I
think that makes the intent the most clear.

> - option-tag should move down near Require

I moved to to after Proxy-Require; this is the first reference to it.

> contact-param = (STAR | name-addr | addr-spec) *(SEMI contact-params)

Hmm. I don't know about that. When Contact is *, parameters have never
been allowed. The semantics are different from Accept-Contact, where
parameters make sense. I would prefer the BNF to follow the semantics
rather then get consistency in the grammar of similar headers.

> needs to have LWS between "Digest" and the params.

Already fixed.

> - general comment.  using <'> instead of "'" would be more readable IMO

Sorry; where is it used?

> disposition-param = "handling" EQUAL ("optional" | "required" |

Already fixed, using that precedence.

> - similar issue with retry-param

Already fixed, using same precedence.

> - Accept and Content Language should use "-" instead of MINUS

Good catch. Fixed.

>         = wkday "," SP date1 SP time SP "GMT"

Yikes, good catch. The whole idea of rfc1123-date is its supposed to be
fixed length.

> - in the definition of digest-chlng the "optional" brackets [] are

Indeed. I had a conversation with the authors of rfc2617 on this. They
indicated that they used [] around parameters that were optional
according to the protocol usage. I have kept that intention here.

> - qop-options  is COMMA apropos or should it be "," SP or "," HWS

I would be inclined to have no lws of any sort here, since lws inside of
quoted string values is just going to far, imho. I changed it to just
","
> gives no mention of the second "delay" token.  is this an error?

The text on delay got lost somewhere... although there isn't much use of
timestamp yet, we finally have a well-defined and documented mechanism
as of bis-05. I will add text on usage of the delay parameter.

> ok,  more later?

Sure...

-Jonathan R.

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