[SIPForum-discussion] Diversion Header Syntax

[Hadriel Kaplan]

The only "RFC" for Diversion syntax is RFC 5806, but it's not a Proposed Standard nor even an IETF RFC.  It's an independent submission through the RFC editor (which is separate form the IETF) and it's historic status.  Having said that, though, it's quite popular. :)

Anyway, the ABNF syntax in RFC 5806 and what you post below does not mean they're in quotes.  The quotes you see around it in the ABNF rules just means they're the literal string as a token, as opposed to the name of an element to be defined in another ABNF rule.  So in fact it should appear as you say - without the quotes.  Unfortunately some of the examples from the draft/RFC showed quotes which leads to confusion, and devices should treat the double-quotes as matching the token if the un-quoted string portion matches.

So to make a long story short, you should generate this:
<sip:xxxxxx at 84.44.72.6>;reason=unconditional;privacy=full;screen=no

But accept this as well as meaning the same thing:
<sip:xxxxxx at 84.44.72.6>;reason="unconditional";privacy="full";screen="no"

-hadriel


On Sep 9, 2011, at 8:33 AM, mustafa aydin wrote:

> Hi Caglar,
>  
> I agree that they are not mandatory, but I can't prove it by RFCs.
>  
> Regards,
> Mustafa
> 
> From: caglar er <beratcaglar at yahoo.com>
> To: mustafa aydin <mustafaydin82 at yahoo.com>; "discussion at sipforum.org" <discussion at sipforum.org>
> Sent: Friday, September 9, 2011 3:06 PM
> Subject: Re: [SIPForum-discussion] Diversion Header Syntax
> 
> I dont think they are mandatory. Most SIP Servers can be able to handle them and generate without quatas. For ex Nortel-Genband SIP devices are also can be able to handle them wıthout quoatas 
>  
>  
> B. Caglar ER
> From: mustafa aydin <mustafaydin82 at yahoo.com>
> To: "discussion at sipforum.org" <discussion at sipforum.org>
> Sent: Thursday, September 8, 2011 2:53 PM
> Subject: [SIPForum-discussion] Diversion Header Syntax
> 
> Hello,
>  
> Can someone tell if the format of the Diversion header below is an acceptable  one, if so how can I prove it with RFCs?
> <sip:xxxxxx at 84.44.72.6>;reason=unconditional;privacy=full;screen=no
> 
> My concern regarding this format  is that  if there must be  quotes around the full  and no values, because as per  the RFC,the syntax is as below, but I found many implementations where there are no quotes around.
>  
>  
>    Diversion = "Diversion" ":" 1# (name-addr *( ";" diversion_params ))  
>    diversion-params = diversion-reason | diversion-counter |
>                       diversion-limit | diversion-privacy |
>                       diversion-screen | diversion-extension
>    diversion-reason = "reason" "="
>                    ( "unknown" | "user-busy" | "no-answer" |
>                      "unavailable" | "unconditional" |
>                      "time-of-day" | "do-not-disturb" |
>                      "deflection" | "follow-me" |
>                      "out-of-service" | "away" |
>                      token | quoted-string )
>    diversion-counter = "counter" "=" 1*2DIGIT
>    diversion-limit = "limit" "=" 1*2DIGIT
>    diversion-privacy = "privacy" "=" ( "full" | "name" |
>                        "uri" | "off" | token | quoted-string )
>    diversion-screen = "screen" "=" ( "yes" | "no" | token |
>                                         quoted-string )
>    diversion-extension = token ["=" (token | quoted-string)]
> .
> Thanks is in advance
> Mustafa AYDIN
> 
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