SS7-ISUP, DSS1 Release Message

SS7-ISUP (32/Q.763 (09/97))

A message sent in either direction to indicate that the circuit is being released due to the reason (cause) supplied and is ready to be put into the idle state on receipt of the release complete message. Where the call is to be redirected the message will also carry the redirection number.

ParameterTypeLength (octets)
Message typeF1
Cause indicatorsV3-?
Redirection informationO3-4
Redirection numberO5-?
Access transportO3-?
Signalling point codeO4
User-to-user informationO3-131
Automatic congestion levelO3
Network specific facilityO4-?
Access delivery informationO3
Parameter compatibility informationO4-?
User-to-user indicatorsO3
Display informationO3-?
Remote operationsO8-?
End of optional parametersOtd>1

DSS1 (3-10/Q.931)

This message is sent by the user or the network to indicate that the equipment sending the message has disconnected the channel (if any) and intends to release the channel and the call reference. Thus the receiving equipment should release the channel and prepare to release the call reference after sending a RELEASE COMPLETE. See Table 3-10.
Information elementDirectionTypeLengthNote
Protocol discriminatorBothM1
Call referenceBothM2-*
Message typeBothM1
Causen->uO2-32
Displayn->uO The minimum length is 2 octets; the maximum length is network dependent and is either 34 or 82 octets.
Signaln->uO2-3
NOTES 1 This message has local significance; however, it may carry information of global significance when used as the first call clearing message. 2 Mandatory in the first call clearing message, including when the RELEASE message is sent as a result of an error handling condition. 3 Included if the network provides information that can be presented to the user. 4 The minimum length is 2 octets; the maximum length is network dependent and is either 34 or 82 octets. 5 Included if the network optionally provides additional information describing tones.