Subject: [SIP] REFER -> Referred-By syntax

From: Eric Tremblay <[email-masked]>
Date: Wed, 27 Sep 2000 17:14:58 -0400

I think the syntax of Referred-By should be reviewed:

1- The parser has to check for "ref" to find the beginning of the
"referenced-url", which (I think) goes against the suggestion in
draft-ietf-sip-guidelines-00.txt (and it badly breaks my parser ;) ):

   Headers that contain a list of URIs SHOULD follow the same syntax as
   the Contact header in SIP. Implementors are also encouraged to always
   wrap these URI in angle brackets "<" and ">". We have found this to
   be a frequently misimplemented feature.

2- The same thing to find the beginning of "ref-signature", the parser has
to look out for "scheme" in the previous URL.

Shouldn't the syntax be something like the following (making the "<" and ">"
brackets mandatory):

     Referred-By      = ("Referred-By" | "b") ":"     referrer-url  
                                                  ";" referenced-url 
                                                 [";" ref-signature] 
     referrer-url     = "<" SIP-URL ">"
     referenced-url   = "<" URL ">"
     ref-signature    = signature-scheme *( ";" sig-scheme-params ) 
     signature-scheme = "scheme" "=" token 
     sig-scheme-parms = token "=" ( token | quoted-string ) 

Best regards,

EricT

-----Original Message-----
From: Robert Sparks [mailto:[email-masked]]
Sent: Tuesday, September 26, 2000 10:06 AM
To: Tom-PT Taylor; [email-masked]
Subject: [SIP] RE: Referred-By: ...referenced-url

Yes.

The referenced party needs to be able to know, with proof, which of the
headers in
the request it receives came from the referrer, and that those headers have
not been
modified.
 
RjS
-----Original Message-----
From: Tom-PT Taylor [mailto:[email-masked]]
Sent: Monday, September 25, 2000 7:03 PM
To: [email-masked]
Cc: [email-masked]'
Subject: Referred-By: ...referenced-url

According to draft-ietf-sip-cc-transfer-01.txt, the referenced-url component
of the Referred-By: header contains a copy of the URL transmitted in the
Refer-To: header.  What if the Refer-To: URL contains headers (e.g.
Accept-Contact:).  Are these also reproduced in Referred-By:, particularly
as it appears in the REFER request?
Tom Taylor 

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From: "Robert Sparks" <[email-masked]>
Date: Wed, 27 Sep 2000 17:00:11 -0500

The -01 syntax follows Contact very closely. ref=, scheme= and
the sig-scheme-params are all header parameters (they come after
the first semicolon after the referred-by URL). You will have
to go through the same level of effort to parse them that you
go through for expires= on a Contact header.

Things creating a Referred-By header SHOULD wrap URIs in <>
wherever they occur, per the below recommendation.

The primary deviation from the spirit of Contact's syntax is
allowing only a SIP-URL for the referrer-url instead of allowing
(name-addr|addr-spec). On reflection, the display-name in name-addr
would probably be useful to parties receiving the header. Are there
objections to allowing that?

RjS
> From: Eric Tremblay [mailto:[email-masked]]
> Sent: Wednesday, September 27, 2000 4:15 PM
> To: 'Robert Sparks'; [email-masked]
> Subject: REFER -> Referred-By syntax
>
>
>