Service specific connection oriented protocol for the ATM adaptation layer

The service specific connection oriented protocol is now being studied for use as the ATM adaptation layer protocol for connection oriented data communication and UNI/NNI signaling in the B-ISDN. The key feature of this protocol is a numbered poll mechanism that enables status information to be exchanged frequently and that is helpful for selective retransmission for frame loss. This paper examines this mechanism from the viewpoints of polling interval and frame length. Because this protocol was designed to perform selective retransmission for error recovery, some requirements, such as saving buffer, are not met. Two enhancements are therefore proposed: one consists of a Go-back-N-like procedure and nonassured credit, and the other is an SD PDU with a P bit. Guidelines to determine the POLL PDU interval are given.<>