Bis05 does not seem to make any difference between Call and CallLeg

Call: A call is an informal term that refers to a dialog between peers,
generally set up for the purposes of a multimedia conversation. 

Call leg: Another name for a dialog. 

Dialog: A dialog is a peer-to-peer SIP relationship between a Various
Authors [Page 13]  Internet Draft SIP October 26, 2001 UAC and UAS that
persists for some time. A dialog is established by SIP messages, such as
a 2xx response to an INVITE request. A dialog is identified by a call
identifier, local address, and remote address. A dialog was formerly
known as a call leg in RFC 2543. 



However in Bis04 

Call: A call consists of all participants in a session invited by a
common source. A SIP call is identified by a globally unique call-id
(Section 10.12), and is created when a user agent sends an INVITE
request. This INVITE request may generate multiple acceptances, each of
which are part of the same call (but different call legs). Furthermore,
if a user is invited to the same multicast session by several people,
each of these invitations will be a unique call. In a multiparty
conference unit (MCU) based call-in conference, each participant uses a
separate call to invite himself to the MCU. 

Call leg: A call leg is a pairwise signaling relationship between two
SIP user agents. A call leg is established when a call invitation
results in a successful response. It is identified by the combination of
the Call-ID header field, the local address of the participant, and the
remote address of the other participant. For the caller, the local
address is the From field of the INVITE, and the remote address is the
To field of the 200 class response. For the callee, the local address is
the To field of the 200 class response to the INVITE, and the remote
address is the From field of the INVITE. SIP URIs are compared according
to Section 2.1, non-SIP URIs according to Section 2.2. Within the same
Call-ID, requests with From A and To value B belong to the same call leg
as the requests in the opposite direction, i.e., From B and To A. 




My question - are we allowed to use same Call-ID for multiple dialogs
for the purpose of a non based MCU multiparty conference?

Thank you,
Radu

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