[Asterisk-Dev] Bug report 4783 and RFC 3326: The Reason Header Field for SIP

[Eric Wieling aka ManxPower]

Mikael Magnusson wrote:
> The Reason header can't be used with only SIP cause values. RFC 3326
> defines support for both SIP and Q.850 protocols. I believe Q.850 codes
> are used by both PRI and H.323. The Reason protocols are registered by
> IANA in http://www.iana.org/assignments/sip-parameters.
> 
> RFC 3326:
> 
> "A SIP message MAY contain more than one Reason value (i.e., multiple
>  Reason lines), but all of them MUST have different protocol values
>  (e.g., one SIP and another Q.850)."
> 
>   The following values for the protocol field have been defined:
> 
>       SIP: The cause parameter contains a SIP status code.
> 
>       Q.850: The cause parameter contains an ITU-T Q.850 cause value
>            in decimal representation.
> 
>    Examples are:
> 
>       Reason: SIP ;cause=200 ;text="Call completed elsewhere"
>       Reason: Q.850 ;cause=16 ;text="Terminated"
>       Reason: SIP ;cause=600 ;text="Busy Everywhere"
>       Reason: SIP ;cause=580 ;text="Precondition Failure"

There's also Integrated Services Digital Network (ISDN) User Part 
(ISUP) to Session Initiation Protocol (SIP) Mapping" aka 
http://www.ietf.org/rfc/rfc3398.txt and "Internal Cause Code 
Consistency Between SIP and H.323" aka 
http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00800b5d65.html

-- 
Always do right. This will gratify some people and astonish the rest.
Mark Twain