Basic Considerations

• Messages for ATM point-to-point call and connection control only state those Information Element which are included in this UNI signaling setup design and excluding those optional type which may be considered not significant in this project.
• Notes to take:
• Direction: Both - user-to-network @ network-to-user
• Type: M  - mandatory
• Type: O  - optional
• Each message is stated with the optimal requirements for an ATM point-to-point call and connection to be established in the network.
• Each number stated at the top of the messages in the ATM UNI signaling design above is hexadecimal base.

 SETUP

• Sent by the calling user to the network and by the network to the called user to initiate call establishment.

Note 1-included in the user-to-network direction when the calling user wants to pass AAL parameter information to the called user. Included in the network-to-user direction if the calling user included an AAL parameters information element in the SETUP message.

Note 2-included by the user to convey called party number information to the network. Included by the network when called party number information is coneyed to the user.

Note 3-may be included by the calling user or the network to identify the calling user.

Note 4-may only be absent when using the non-associated signalling procedure.

CALL PROCEEDING

• To indicate that the requested call establishment has been initiated and no more call establishment information will be accepted.

Note 1-mandatory in the network-to-user direction if this message is the first message in response to a SETUP message. Mandatory in the user-to-network direction if this message is the first message in response to a SETUP message, unless the user accepts the connection identifier indicated in the SETUP message.

CONNECT

• To indicate call acceptance by the called user.

Note 1-mandatory in the network-to-user direction if this message is the first message in response to a SETUP message. Mandatory in the user-to-network direction if this message is the first message in response to a SETUP message, unless the user accepts the connection identifier indicated in the SETUP message.

CONNECT ACKNOWLEDGE

• Sent by the network to the called user to indicate the user has been awarded the call. Sent by the calling user to the network to allow symmetrical call control procedures.

RELEASE

• Sent by the user to request the network to clear the end-to-end connection(if any) or is sent by the network to indicate that the end-to-end connection is cleared and that the receiving equipment should release the virtual channel and prepare to release the call reference after sending a RELEASE COMPLETE.

 RELEASE COMPLETE

• Sent by the user or the network to indicate that the equipment sending the message has released the virtual channel(if any) and call reference, the virtual channel is available for reuse, and the receiving equipment shall release the call reference.

Note 1-mandatory in the first call clearing message; including when the RELEASE COMPLETE message is sent as a result of an error condition.