|<========================>| |<=======================>|
| | | |
Figure 5: Typical message sequence for successful call establishment
from QSIG to SIP, using overlap procedures on both QSIG and SIP
1 The PISN sends a QSIG SETUP message to the gateway to begin a
session with a SIP UA. The QSIG SETUP message does not contain a
Sending complete information element.
2 The gateway sends a QSIG SETUP ACKNOWLEDGE message to the PISN.
More digits are expected.
3 More digits are sent from the PISN within a QSIG INFORMATION
message.
4 When the gateway receives the minimum number of digits required to
route the call, it generates a SIP INVITE request and sends it to
an appropriate SIP entity in the IP network based on the called
number
5 Due to an insufficient number of digits, the IP network will
return a SIP 484 (Address Incomplete) response.
6 The SIP 484 (Address Incomplete) response is acknowledged.
7 More digits are received from the PISN in a QSIG INFORMATION
message. A new INVITE is sent with the same Call-ID and From
values but an updated Request-URI.
8 More digits are received from the PISN in a QSIG INFORMATION
message. The QSIG INFORMATION message contains a Sending Complete
information element.
9 The gateway sends a QSIG CALL PROCEEDING message to the PISN; no
more information will be accepted.
10 The gateway sends a new SIP INVITE request with an updated
Request-URI field.
11 The IP network sends a SIP 100 (Trying) response to the gateway.
12 The IP network sends a SIP 180 (Ringing) response.
13 The gateway may send back a SIP PRACK request to the IP network
based on the inclusion of a Require header or a Supported header
with option tag 100rel in the initial SIP INVITE request.
14 The IP network sends a SIP 200 (OK) response to the gateway to
acknowledge the SIP PRACK request.
15 The gateway maps this SIP 180 (Ringing) response to a QSIG
ALERTING message and sends it to the PISN.
16 The IP network sends a SIP 200 (OK) response when the call is
answered.
17 The gateway sends a SIP ACK request to acknowledge the SIP 200
(OK) response.
18 The gateway maps this SIP 200 (OK) response to a QSIG CONNECT
message.
19 The PISN sends a QSIG CONNECT ACKNOWLEDGE message in response to
the QSIG CONNECT message.
A.3. Message sequences for call establishment from SIP to QSIG
Below are typical message sequences for successful call establishment
from SIP to QSIG
A.3.1. SIP to QSIG, using en bloc procedures
+----------------------+
IP NETWORK | GATEWAY | PISN
| |
| +-------+-------+------+ |
| | | |
| | | |
| 1-INVITE | | QSIG SETUP |
1 |------------------------->|.......|------------------------>|3
| 1-100 TRYING | | QSIG CALL PROCEEDING |
2 |<-------------------------| |<------------------------|4
| 1-180 RINGING | | QSIG ALERTING |
6 |<-------------------------|.......|<------------------------|5
| | | |
| | | |
| 2-PRACK | | |
7 |------------------------->| | |
| 2-200 OK | | |
8 |<-------------------------| | |
| 1-200 OK | | QSIG CONNECT |
11|<-------------------------|.......|<------------------------|9
| | | |
| 1-ACK | | QSIG CONNECT ACK |
12|------------------------->| |------------------------>|10
| AUDIO | | AUDIO |
|<========================>| |<=======================>|
| | | |
Figure 6: Typical message sequence for successful call establishment
from SIP to QSIG, using en bloc procedures
1 The IP network sends a SIP INVITE request to the gateway.
2 The gateway sends a SIP 100 (Trying) response to the IP network.
3 On receipt of the SIP INVITE request, the gateway sends a QSIG
SETUP message.
4 The PISN sends a QSIG CALL PROCEEDING message to the gateway.
5 A QSIG ALERTING message is returned to indicate that the end user
in the PISN is being alerted.
6 The gateway maps the QSIG ALERTING message to a SIP 180 (Ringing)
response.
7 The IP network can send back a SIP PRACK request to the IP network
based on the inclusion of a Require header or a Supported header
with option tag 100rel in the initial SIP INVITE request.
8 The gateway sends a SIP 200 (OK) response to acknowledge the SIP
PRACK request.
9 The PISN sends a QSIG CONNECT message to the gateway when the call
is answered.
10 The gateway sends a QSIG CONNECT ACKNOWLEDGE message to
acknowledge the QSIG CONNECT message.
11 The QSIG CONNECT message is mapped to a SIP 200 (OK) response.
12 The IP network, upon receiving a SIP INVITE final response (200),
will send a SIP ACK request to acknowledge receipt.
A.3.2. SIP to QSIG, using overlap receiving on SIP and en bloc sending
on QSIG
+----------------------+
IP NETWORK | GATEWAY | PISN
| |
| 1-INVITE +-------+-------+------+ |
1 |------------------------->| | |
| 1-484 | | |
2 |<-------------------------| | |
| 1-ACK | | |
3 |------------------------->| | |
| 2-INVITE | | |
1 |------------------------->| | |
| 2-484 | | |
2 |<-------------------------| | |
| 2- ACK | | |
3 |------------------------->| | |
| 3-INVITE | | QSIG SETUP |
4 |------------------------->|.......|------------------------>|6
| 3-100 TRYING | | QSIG CALL PROCEEDING |
5 |<-------------------------| |<------------------------|7
| 3-180 RINGING | | QSIG ALERTING |
9 |<-------------------------|.......|<------------------------|8
| | | |
| | | |
| 4-PRACK | | |
10|------------------------->| | |
| 4-200 OK | | |
11|<-------------------------| | |
| 3-200 OK | | QSIG CONNECT |
14|<-------------------------|.......|<------------------------|12
| | | |
| 3-ACK | | QSIG CONNECT ACK |
15|------------------------->| |------------------------>|13
| AUDIO | | AUDIO |
|<========================>| |<=======================>|
| | | |
Figure 7: Typical message sequence for successful call establishment
from SIP to QSIG, using overlap receiving on SIP and en bloc sending
on QSIG
1 The IP network sends a SIP INVITE request to the gateway.
2 Due to an insufficient number of digits, the gateway returns a SIP
484 (Address Incomplete) response.
3 The IP network acknowledges the SIP 484 (Address Incomplete)
response.
4 The IP network sends a new SIP INVITE request with the same Call-
ID and updated Request-URI.
5 The gateway now has all the digits required to route the call to
the PISN. The gateway sends back a SIP 100 (Trying) response.
6 The gateway sends a QSIG SETUP message.
7 The PISN sends a QSIG CALL PROCEEDING message to the gateway.
8 A QSIG ALERTING message is returned to indicate that the end user
in the PISN is being alerted.
9 The gateway maps the QSIG ALERTING message to a SIP 180 (Ringing)
response.
10 The IP network can send back a SIP PRACK request to the IP network
based on the inclusion of a Require header or a Supported header
with option tag 100rel in the initial SIP INVITE request.
11 The gateway sends a SIP 200 (OK) response to acknowledge the SIP
PRACK request.
12 The PISN sends a QSIG CONNECT message to the gateway when the call
is answered.
13 The gateway sends a QSIG CONNECT ACKNOWLEDGE message to
acknowledge the CONNECT message.
14 The QSIG CONNECT message is mapped to a SIP 200 (OK) response.
15 The IP network, upon receiving a SIP INVITE final response (200),
will send a SIP ACK request to acknowledge receipt.
A.3.3. SIP to QSIG, using overlap procedures on both SIP and QSIG
+----------------------+
IP NETWORK | GATEWAY | PISN
| |
| 1-INVITE +-------+-------+------+ |
1 |------------------------->| | |
| 1-484 | | |
2 |<-------------------------| | |
| 1-ACK | | |
3 |------------------------->| | |
| 2-INVITE | | QSIG SETUP |
4 |------------------------->|.......|------------------------>|6
| 2-100 TRYING | | QSIG SETUP ACK |
5 |<-------------------------| |<------------------------|7
| 3- INVITE | | QSIG INFORMATION |
8 |------------------------->|.......|------------------------>|10
| 3-100 TRYING | | |
9 |<-------------------------| | QSIG CALL PROCEEDING |
| | |<------------------------|11
13| 3-180 RINGING | | QSIG ALERTING |
|<-------------------------|.......|<------------------------|12
| 2-484 | | |
14|<-------------------------| | |
| 2-ACK | | |
15|------------------------->| | |
| 4-PRACK | | |
16|------------------------->| | |
| 4-200 OK | | |
17|<-------------------------| | |
| 3-200 OK | | QSIG CONNECT |
20|<-------------------------|.......|<------------------------|18
| | | |
| 3-ACK | | QSIG CONNECT ACK |
21|------------------------->| |------------------------>|19
| AUDIO | | AUDIO |
|<========================>| |<=======================>|
| | | |
Figure 8: Typical message sequence for successful call establishment
from SIP to QSIG, using overlap procedures on both SIP and QSIG
1 The IP network sends a SIP INVITE request to the gateway.
2 Due to an insufficient number of digits, the gateway returns a SIP
484 (Address Incomplete) response.
3 The IP network acknowledges the SIP 484 (Address Incomplete)
response.
4 The IP network sends a new SIP INVITE request with the same
Call-ID and updated Request-URI.
5 The gateway now has all the digits required to route the call to
the PISN. The gateway sends back a SIP 100 (Trying) response to
the IP network.
6 The gateway sends a QSIG SETUP message.
7 The PISN needs more digits to route the call and sends a QSIG
SETUP ACKNOWLEDGE message to the gateway.
8 The IP network sends a new SIP INVITE request with the same
Call-ID and From values and updated Request-URI.
9 The gateway sends back a SIP 100 (Trying) response to the IP
network.
10 The gateway maps the new SIP INVITE request to a QSIG INFORMATION
message.
11 The PISN has all the digits required and sends back a QSIG CALL
PROCEEDING message to the gateway.
12 A QSIG ALERTING message is returned to indicate that the end user
in the PISN is being alerted.
13 The gateway maps the QSIG ALERTING message to a SIP 180 (Ringing)
response.
14 The gateway sends a SIP 484 (Address Incomplete) response for the
previous SIP INVITE request.
15 The IP network acknowledges the SIP 484 (Address Incomplete)
response.
16 The IP network can send back a SIP PRACK request to the IP network
based on the inclusion of a Require header or a Supported header
with option tag 100rel in the initial SIP INVITE request.
17 The gateway sends a SIP 200 (OK) response to acknowledge the SIP
PRACK request.
18 The PISN sends a QSIG CONNECT message to the gateway when the call
is answered.
19 The gateway sends a QSIG CONNECT ACKNOWLEDGE message to
acknowledge the QSIG CONNECT message.
20 The QSIG CONNECT message is mapped to a SIP 200 (OK) response.
21 The IP network, upon receiving a SIP INVITE final response (200),
will send a SIP ACK request to acknowledge receipt.
A.4. Message Sequence for Call Clearing from QSIG to SIP
Below are typical message sequences for Call Clearing from QSIG to
SIP
A.4.1. QSIG to SIP, subsequent to call establishment
+-------------------+
| |
| GATEWAY |
PISN | | IP NETWORK
| +-----+------+------+ |
| | | |
| | | |
| QSIG DISCONNECT | | 2- BYE |
1|----------------------->|......|----------------------->|4
| QSIG RELEASE | | 2-200 OK |
2|<-----------------------| |<-----------------------|5
| QSIG RELEASE COMP | | |
3|----------------------->| | |
| | | |
| | | |
| | | |
Figure 9: Typical message sequence for call clearing from QSIG to
SIP, subsequent to call establishment
1 The PISN sends a QSIG DISCONNECT message to the gateway.
2 The gateway sends back a QSIG RELEASE message to the PISN in
response to the QSIG DISCONNECT message.
3 The PISN sends a QSIG RELEASE COMPLETE message in response. All
PISN resources are now released.
4 The gateway maps the QSIG DISCONNECT message to a SIP BYE request.
5 The IP network sends back a SIP 200 (OK) response to the SIP BYE
request. All IP resources are now released.
A.4.2. QSIG to SIP, during establishment of a call from SIP to QSIG
+-------------------+
| |
| GATEWAY |