No subject

from-spec = ( name-addr / addr-spec ) *( SEMI from-param )
name-addr = [ display-name ] LAQUOT addr-spec RAQUOT
display-name   =  *(token LWS)/ quoted-string
addr-spec =  SIP-URI / SIPS-URI / absoluteURI

For my purposes I would need one of these From headers:

(1) From: sip:0123456789 at server <-- no display name
(2) From: <sip:0123456789 at server> <-- empty display name
(3) From: "" <sip:0123456789 at server> <-- empty display name


I've tested option (2) on the Avaya IP500 and it fixes so name matching
works: the phone book does what it's supposed to.

I chose option (2) over (1) and (3) because:
(1) Might cause incompatibilities with bad SIP parsers.
(3) Is overly explicit that the name is empty when we actually mean
    that the name is not set.



The supplied patches do just this:
* Allow CALLERID(name) to be empty.
* If CALLERID(name) is empty, send the From-header as (2).


Caveats:
The only drawback I see is that some people that expect the display-name
to be automatically set to CALLERID(num) would be disappointed. This is
usually fixed by a simple dialplan change though.


Regards,
Walter Doekes
OSSO B.V.
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Issue History 
Date Modified    Username       Field                    Change               
====================================================================== 
2010-06-03 03:46 wdoekes        Summary                  SIP display-name needed
to be empty for Avaya IP500 => [patch] SIP display-name needed to be empty for
Avaya IP500
======================================================================