What is a connection oriented service?

To send data from one device to another, a connection must be established. Data transfer between devices can be accomplished in two ways:

• Connection Oriented Service

• Connectionless Service

A connection oriented service requires establishing a dedicated communication path between sender and receiver before any data transmission begins. This approach ensures reliable and ordered delivery of data packets.

How Connection Oriented Service Works

Connection oriented service follows a three-phase process:

• Connection establishment − A reliable connection is established between sender and receiver

• Data transfer − Information is transmitted over the established connection

• Connection termination − The connection is properly closed after data transfer completes

Key Characteristics

• Guaranteed delivery − The network ensures all packets are delivered in order without loss or duplication

• Single path transmission − All data follows the same established path between endpoints

• Bandwidth reservation − A minimum amount of bandwidth is reserved for the duration of the connection

• Flow control − The network can refuse new connection requests if resources are overutilized

• Error recovery − Built-in acknowledgment and retransmission mechanisms handle damaged or lost frames

Connection Establishment Process

Connection establishment typically follows a three-way handshake:

• Step 1 − Sender requests connection by sending a connection request packet

• Step 2 − Receiver returns a confirmation packet accepting the connection

• Step 3 − Sender acknowledges the confirmation, establishing the connection

Service Primitives

Connection oriented services use four main primitives:

Examples

The most common example of a connection oriented service is Transmission Control Protocol (TCP), which provides reliable data delivery for web browsing, email, and file transfers. Other examples include virtual circuit services in packet-switched networks.

Conclusion

Connection oriented service provides reliable, ordered data transmission through a three-phase process of connection establishment, data transfer, and connection termination. While it requires more overhead than connectionless services, it guarantees data integrity and delivery, making it ideal for applications requiring reliable communication.