Defining “Connection-less” and “Connection-Oriented”

The terms ‘connectionless’ and ‘connection-oriented’ are sometimes used in confusing ways. Let’s set the record straight in a way that would satisfy the demands of a network expert.

Connectionless And Datagram Mean The Same Thing

A connectionless protocol (or protocol layer) does not have a sequence number and acknowledgment scheme. That’s all. No sequence numbers mean that a protocol is ‘connectionless’. It could also be referred to as a ‘datagram’.

Connection-Oriented And Reliable Mean The Same Thing

A connection-oriented protocol (or protocol layer) has sequence numbers and an expected acknowledgment process. If acknowledgments are not received then retransmission will occur. In this way, a connection-oriented protocol can guarantee delivery of data. That’s all. If a protocol has sequence numbers then it’s ‘connection-oriented’. It could also be referred to as a reliable protocol.

Topics In This Discussion

• Introduction to LLC Layer
• Defining “Connection-less” and “Connection-Oriented”
• Type 1 Logical Link Control
• Setting Up a Type II LLC Connection
• Transmitting and Acknowledging
• Data in Type II LLC
• Protocol Analysis Techniques for Type II LLC
• The Bits in the LLC Header
• Type 2 LLC Commands and Responses
• Type II LLC Commands and Responses
• Viewing LLC with your Protocol Analyzer
• The Rationale for Using a Reliable Data Link