Subject: [Sip] ABNF for Replaces header

From: "Ganesh Sivaraman" <[email-masked]>
Date: Wed, 10 Jul 2002 15:05:22 +0530

Hi,
  Following is the ABNF for Replaces header as specified in draft-ietf-sip-replaces-02.txt:
 
Replaces = "Replaces" HCOLON callid *(SEMI replaces-param)
replaces-param = to-tag / from-tag / generic-param
to-tag = "to-tag" EQUAL token
from-tag = "from-tag" EQUAL token
 
According to this I could have Replaces headers like:
 
Replaces: abcd@efgh;to-tag=sdfsd --> (i)
Replaces: 1234ab@cde4 --> (ii)
 
But the text right below the Replaces header's definition in the draft states the following:
 
"A Replaces header MUST contain exactly one to-tag and exactly one from-tag, as they are required for unique dialog matching".
 
According to this textual description the above examples ( i & ii) are incorrect.
 
The ABNF doesn't seem to be matching this textual description. Is this a bug with the ABNF?
 
Thanks & Regards
Ganesh