Business Data Networks and Security 9th Edition Panko Solutions Manual

Making connectionless protocol reliable

Protocols are a set of rules that need to be implemented in software and run by two nodes that need to exchange data.

Examples of protocols:

• TCP (Transmission Control Protocol)

• UDP (User Data Gram Protocol)

• Ethernet

• IP (Internet Protocol)

Except TCP all are connectionless protocols. TCP is connection-oriented protocol.

There are primarily two types of protocols:

1. Connection Oriented Protocols

2. Connectionless Protocols

Both types of protocols are described below:

1. Connection-oriented protocol:

• Connection-oriented protocol allows each message that has to effectively transmitted, to have unique number.

• This number is known as the sequence number. The sequence number plays an important role of ensuring that no message is missing during transmission.

• An example of Connection-oriented protocol is the TCP protocol.

• TCP is a reliable protocol, which implies to have the mechanism essential for error correction.

2. Connection less protocols:

• Connection-less protocol are relatively less reliable for transmission of messages.

• Data unit, is given a destination address, and is sent.

• No prior path, for an effective dialog of message transmitted, is established. Internet Protocol and User Datagram Protocol are some examples of connectionless protocols.

Major challenge on connectionless protocol is lack of a proper error correction mechanism. This can often cause malfunctioning, leading to incorrect delivery of messages.

Ensuring reliability in connectionless protocol:

Usually, the alternative to connectionless protocol is connection oriented protocol. But the short comings, of connectionless protocols can be resolved, at least to ensure reliability.

• Reliable connectionless protocols, can establish a firm 1-way communication without the complication, of creating and then destroying a dedicated channel, solely for the process.

• This can be achieved, by using the transport layer features.

• The transport layer breaks the data, into several fixed sized message components, or packets.

• Then the layer generates a header for each such packet.

• Header describes sequences, keeping the given original data, in view.

• Following this, the packets are transferred to destination node.

• When they are received, destination node compiles the packets based on information in header.

• In brief, the process is a modification of the TCP protocol.

• Other ways, can also, to use those algorithms that are responsible for connection-oriented protocols.

• Such algorithms may provide error detection methods and congestion-control schemes.

In this way, it is possible to achieve reliability up to some extent using connectionless protocols.

Therefore, it is not possible achieve 100% reliability using connectionless protocols.