Messages decoded by dectrace

dectrace decodes ISDN layer 3 messages in accordance with Q.931/Q.932 specifications, except where noted.

Q.931/Q.932 message types

dectrace decodes all the messages types defined in the Q.931/Q.932 specifications. The following table lists the messages types:

Message

Hexadecimal value

Notes

Escape to nationally specific message type:

MSG_ESCAPE

0x00

Q.931

Call establishing messages:

MSG_ALERTING

0x01

Q.931

MSG_CALL_PROC

0x02

Q.931

MSG_PROGRESS

0x03

Q.931

MSG_SETUP

0x05

Q.931

MSG_CONNECT

0x07

Q.931

MSG_SETUP_ACK

0x0D

Q.931

MSG_CONNECT_ACK

0x0F

Q.931

Call information phase messages:

MSG_USER_INFO

0x20

Q.931

MSG_SUSPEND_REJ

0x21

Q.931

MSG_RESUME_REJ

0x22

Q.931

MSG_HOLD

0x24

Q.932

MSG_SUSPEND

0x25

Q.931

MSG_RESUME

0x26

Q.931

MSG_HOLD_ACK

0x28

Q.932

MSG_SUSPEND_ACK

0x2D

Q.931

MSG_RESUME_ACK

0x2E

Q.931

MSG_HOLD_REJ

0x30

Q.932

MSG_RETRIEVE

0x31

Q.932

MSG_RETRIEVE_ACK

0x33

Q.932

MSG_RETRIEVE_REJ

0x37

Q.932

Call clearing messages:

MSG_DISCONNECT

0x45

Q.931

MSG_RESTART

0x46

Q.931

MSG_RELEASE

0x4D

Q.931

MSG_RESTART_ACK

0x4E

Q.931

MSG_RELEASE_COMP

0x5A

Q.931

Miscellaneous messages:

MSG_SEGMENT

0x60

Q.931

MSG_FACILITY

0x62

Q.931

MSG_REGISTER

0x34

Q.932

MSG_NOTIFY

0x6E

Q.931

MSG_STATUS_ENQ

0x75

Q.931

MSG_CONGESTION_CTRL

0x79

Q.931

MSG_INFO

0x7B

Q.931

MSG_STATUS

0x7D

Q.931

Messages not defined in Q.931/Q.932:

MSG_SERVICE

0x0F

According to 235-900-342 (5ESS)

MSG_SERVICE_ACK

0x07

According to 235-900-342 (5ESS)

Information elements

dectrace decodes all the information element identifiers defined in the Q.931/Q.932 specifications. The following table lists the information element identifiers:

Message

Hexadecimal value

Notes

Single octet information elements:

IE_SHIFT

0x90

All values from 0x90 to 0x9F indicate shift

IE_MORE_DATA

0xA0

More data

IE_SENDING_COMPL

0xA1

Sending complete

IE_CONG_LEVEL

0xB0

All values from 0xB0 to 0xBF indicate congestion level

IE_REPEAT_IND

0xD0

All values from 0xD0 to 0xDF indicate repeat indicator

Variable length information elements:

IE_SEGMENTED

0x00

Segmented message

IE_BC

0x04

Bearer capability

IE_CAUSE

0x08

Cause

IE_CONNECTED

0xC

Connected party number

IE_CALL_ID

0x10

Call identity

IE_CALL_STATE

0x14

Call state

IE_CHANNEL_ID

0x18

Channel identification

IE_FACILITY

0x1C

Facility

IE_PROGRESS_IND

0x1E

Progress indicator

IE_NSF

0x20

Network-specific facilities

IE_NOTIFY_IND

0x27

Notification indicator

IE_DISPLAY

0x28

Display

IE_DATE_TIME

0x29

Date/time

IE_KEYPAD

0x2C

Keypad facility

IE_INFO_RQ

0x32

Information request

IE_SIGNAL

0x34

Signal

IE_SWITCHHOOK

0x36

Switchhook

IE_FEATURE_ACK

0x38

Feature activation

IE_FEATURE_IND

0x39

Feature indication

IE_SERVICE_PROF

0x3A

Service profile identification

IE_ENDPOINT_ID

0x3B

Endpoint identifier

IE_INFO_RATE

0x40

Information rate

IE_END_TO_END_DELAY

0x42

End to end transit delay

IE_TDSI

0x43

Transit delay selection and indication

IE_PKT_BIN_PAR

0x44

Packet layer binary parameters

IE_PKT_WIN_SIZE

0x45

Packet layer window size

IE_PKT_SIZE

0x46

Packet size

IE_MIN_THR_CLASS

0x47

Minimum throughput class

IE_CONNECTED_QSIG

0x4C

Connected party number (QSIG)

IE_CALLING

0x6C

Calling party number

IE_CALLING_SUB

0x6D

Calling party subaddress

IE_CALLED

0x70

Called party number

IE_CALLED_SUB

0x71

Called party subaddress

IE_ORIG_CALLED

0x73

Original called number

IE_REDIRECTING

0x74

Redirecting number

IE_REDIRECTION

0x76

Redirection number

IE_TRANSIT_SEL

0x78

Transit network selection

IE_REST_IND

0x79

Restart indicator

IE_LLC

0x7C

Low layer compatibility

IE_HLC

0x7D

High layer compatibility

IE_UUI

0x7E

User-to-user information

IE_ESCAPE

0xFF

Escape for extension

Information elements not defined in Q.931/Q.932:

IE_CHANGE_STATUS

0x01

Change status according to 235-900-342 (5ESS)

If the program does not decode the contents of an information element, it displays:

IE ie_name: NOT DECODED

If the program does not decode the contents of one octet inside one information element, it displays:

octet octet_number: NOT DECODED

If dectrace encounters a value in the message type, the information element ID, or the information element contents that:

Note: The presence of RESERVED or UNKNOWN fields in the program output does not necessarily indicate a failure. Values that are illegal in the Q.931/Q.932 specification may be legal depending on the variant you are running.