Re: [Sipping] draft-york-sipping-p-charge-info-12: ABNF

[Brett Tate <[e-mail]>]

> > In the ABNF section, "chargeparam" is intended to represent that you
> > could optionally have the "noa", "npi" parameters - or any other
> > generic parameters found in RFC 3261(such as "user=phone")
> 
> Including generic-param is a mechanism for making the syntax compatible
> with future enhancements. But allowing it syntactically doesn't specify
> how parameters that match generic-param are to be processed if the are
> present on this header. Typically you would specify in the draft that
> they should be ignored unless the behavior is defined by some other
> specification.

If charge-param remains within userinfo, generic-param should likely be changed to a more limited extention parameter since UTF8-NONASCII is not allowed within SIP-URI and tel URI because of escaping limitations.  RFC 3986 provides a mechanism for escaping UTF8-NONASCII within newer URI schemes.

RFC 3261:

generic-param  =  token [ EQUAL gen-value ]

gen-value      =  token / host / quoted-string

quoted-string  =  SWS DQUOTE *(qdtext / quoted-pair ) DQUOTE

qdtext     =  LWS / %x21 / %x23-5B / %x5D-7E / UTF8-NONASCII