Connection-Oriented Service

Connection-Oriented Service is basically a technique that is typically used to transport and send data at session layer. The data streams or packets are transferred or delivered to receiver in a similar order in which they have seen transferred by sender. It is actually a data transfer method among two devices or computers in a different network, that is designed and developed after telephone system. Whenever a network implements this service, it sends or transfers data or message from sender or source to receiver or destination in correct order and manner.

This connection service is generally provided by protocols of both network layer (signifies different path for various data packets that belongs to same message) as well as transport layer (use to exhibits independence among packets rather than different paths that various packets belong to same message will follow).

Operations :
There is a sequence of operations that are needed to b followed by users. These operations are given below :

1. Establishing Connection –
   It generally requires a session connection to be established just before any data is transported or sent with a direct physical connection among sessions.
2. Transferring Data or Message –
   When this session connection is established, then we transfer or send message or data.
3. Releasing the Connection –
   After sending or transferring data, we release connection.

Different Ways :
There are two ways in which connection-oriented services can be done. These ways are given below :

1. Circuit-Switched Connection –
   Circuit-switching networks or connections are generally known as connection-oriented networks. In this connection, a dedicated route is being established among sender and receiver, and whole data or message is sent through it. A dedicated physical route or a path or a circuit is established among all communication nodes, and after that, data stream or message is sent or transferred.
2. Virtual Circuit-Switched Connection –
   Virtual Circuit-Switched Connection or Virtual Circuit Switching is also known as Connection-Oriented Switching. In this connection, a preplanned route or path is established before data or messages are transferred or sent. The message Is transferred over this network is such a way that it seems to user that there is a dedicated route or path from source or sender to destination or receiver.

Types of Connection-Oriented Service :

Service	Example
Reliable Message Stream	Sequence of pages, etc.
Reliable Byte Stream	Song Download, etc.
Unreliable Connection	VoIP (Voice Over Internet Protocol)

Advantages :

• It kindly support for quality of service is an easy way.
• This connection is more reliable than connectionless service.
• Long and large messages can be divided into various smaller messages so that it can fit inside packets.
• Problems or issues that are related to duplicate data packets are made less severe.

Disadvantages :

In this connection, cost is fixed no matter how traffic is.

It is necessary to have resource allocation before communication.

If any route or path failures or network congestions arise, there is no alternative way available to continue communication.