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CHAPTER 2 NDA-24305
Page 4
Revision 1.0
GENERAL INFORMATION
3. BASIC KNOWLEDGE
3.1 MESSAGE SEQUENCES FOR LAYER 3
The message sequence for call establishment and clearing is shown in Figure 2-2.
Figure 2-2 Message Sequences for Layer3
Note 1:
<Call established message> <Call clearing message>
ALERT: Alerting DISC: Disconnect
CALL PROC: Call Proceeding REL: Release
CONN: Connect RELCOM: Release Complete
CONN ACK: Connect Acknowledge
PROGRESS: Progress
SETUP: Setup
Note 2:
The number in ( ) shows Call state value for User or Network.
State of
Originating
User Side
Null
(0)
Call Initiated
(1)
OG call
Proceeding
(3)
Call Delivered
(4)
Active
(10)
Disconnect
Request
(11)
Null
(0)
Null
(0)
Call Initiated
(1)
OG call
Proceeding
(3)
Call Delivered
(4)
Active
(10)
Disconnect
Request
(11)
Null
(0)
Null
(0)
Call Present
(6)
IC call
Proceeding
(9)
Call Received
(7)
Active
(10)
Disconnect
Indication
(12)
Null
(0)
State of
Te r mi na t in g
User Side
Null
(0)
Call Present
(6)
IC call
Proceeding
(9)
Call Received
(7)
Active
(10)
Disconnect
Indication
(12)
Null
(0)
State of Network
OG Side
IC Side
Release
Request
(19)
Release
Request
(19)
Connect
Request
(8)
Connect
Request
(8)
SETUP
CALL PROC
ALERT/PROG
CONN
CONN ACK
DISC
REL
RELCOM
SETUP
CALL PROC
ALERT/PROG
CONN ACK
DISC
REL
RELCOM
CONN