Q933 + Annex A

Q933 Message structure: fields

- Octet 1: mandatory
bits 8-1 Protocol discriminator (08 H)
- Octet 2: mandatory
bits 8-5 0000
bits 4-1 Length of call reference value (1 or 2 octets)
- Octet 3: mandatory
bit 8 Call reference flag
set to 0 if the message is sent from the side that originates the call reference
set to 1 if the message is sent to the side that originates the call reference.
bits 7-1 Call reference value, assigned by the originating side of the interface for a call.
- Octet 4: exists only if octet 2 = 00000010
bits 8-1 Call reference value (Low order octet)
- Octet: mandatory
bit 8 0
bits 7-1 Message type
- Octets: optional
bits 8-1 One or several information element(s)

Q933 Message structure: list of types

bits 8 _ _ _ _ _ _ 1 hex Message type
0 0 0 _ _ _ _ _ Call establishment messages
0 0 0 0 1 01 ALERTING
0 0 0 1 0 02 CALL PROCEEDING
0 0 1 1 1 07 CONNECT
0 1 1 1 1 0F CONNECT ACKNOWLEDGE
0 0 0 1 1 03 PROGRESS
0 0 1 0 1 05 SETUP
0 1 0 _ _ _ _ _ Call clearing messages
0 0 1 0 1 45 DISCONNECT
0 1 1 0 1 4D RELEASE
1 1 0 1 0 5A RELEASE COMPLETE
0 1 1 _ _ _ _ _ Miscellaneous messages
0 0 0 0 0 60 SEGMENT
1 1 1 0 1 7D STATUS
1 0 1 0 1 75 STATUS ENQUIRY

Q933 Message structure: list of IE

The code values of the information element identifier (first octet of the IE) for the variable length formats are assigned in ascending numerical order, according to the actual order of appearance of each IE in a message. Single octet IE may appear at any point in the message.

Information Element Codeset 0

bits 8 _ _ _ _ _ _ 1 hex Single octet IE
1 0 0 1 _ _ _ _ 9_ Shift
1 0 1 _ _ _ _ D_ Repeat Indicator
bits 8 _ _ _ _ _ _ 1 hex Variable length IE
0 0 0 0 0 0 0 0 00 Segmented Message
0 0 0 0 1 0 0 04 Bearer Capability
0 0 0 1 0 0 0 08 Cause
0 0 1 0 1 0 0 14 Call State
0 0 1 1 0 0 0 18 Channel Identification
0 0 1 1 0 0 1 19 Data Link Connection Identifier
0 0 1 1 1 1 0 1E Progress Indicator
0 1 0 0 0 0 0 20 Network Specific Facilities
0 1 0 1 0 0 0 28 Display
1 0 0 0 0 1 0 42 End-to-end Transit Delay
1 0 0 0 1 0 0 44 Packet Layer Binary Parameters
1 0 0 1 0 0 0 48 Link layer Core Parameters
1 0 0 1 0 0 1 49 Link layer Protocol Parameters
1 0 0 1 1 0 0 4C Connected Number
1 0 0 1 1 0 1 4D Connected Subaddress
1 0 1 0 0 0 0 50 X213 Priority
1 0 1 0 0 0 1 51 Report Type
1 0 1 0 0 1 1 53 Link Integrity Verification
1 0 1 0 1 1 1 57 PVC Status
1 1 0 1 1 0 0 6C Calling Party Number
1 1 0 1 1 0 1 6D Calling Party Subaddress
1 1 1 0 0 0 0 70 Called Party Number
1 1 1 0 0 0 1 71 Called Party Subaddress
1 1 1 1 0 0 0 78 Transit Network Selection
1 1 1 1 1 0 0 7C Low-Layer Compatility
1 1 1 1 1 0 1 7D High Layer Compatibility
1 1 1 1 1 1 0 7E User-User
1 1 1 1 1 1 1 7F Escape for extension

Q933 Annex A message structure: fields

- Octet 1: mandatory
bits 8-1 Protocol discriminator (08 H)
- Octet 2: mandatory
bits 8-1 00000000 = dummy call reference
- Octet 3: mandatory
bit 8 0
bits 7-1 Message type (Status Enquiry or Status)
- Octets: mandatory
bits 8-1 Report type IE
- Octet: optional
bits 8-1 One or several other IE’s (Link Integrity Verification or PVC status)

Q933 Annex A parameters: number list

N391
Description Every N391 polling cycles ,full status (status of all PVCs) is requested.
Value 1-255, 6 by default.
N392
Description Number of errors during N393 monitored events which cause the channel/user side procedures to be declare inactive. Can be used to test the network side procedures.
Value 1-10, 3 by default.
N393
Description Amount of monitored events (Status Enquiry message or T392 expiration) to be used in relation with N392.
Value 1-10, 4 by default.

Q933 Annex A parameters: time-limit list

T391
Description Link integrity verification polling timer.
Started on transmission of Status Enquiry message.
Value 5-30s, 10s by default.
T392
Description Timer for verification of polling cycle.
Started on transmission of Status message.
Stopped on reception of Status Enquiry message.
Value 5-30s, 10s by default.

 


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updated:  27-Feb-04