TCP and UDP

TCP and UDP are two of the most well-known protocols used in computer networking. TCP stands for Transmission Control Protocol and operates on a best-effort principle while UDP uses a datagram approach. This article will highlight the difference between these two protocols.

What is TCP?

Transmission Control Protocol (TCP) is an internet service used for transferring large blocks of data in real-time. A TCP connection works by establishing a virtual circuit between two hosts. The transmission process begins with the sender of the data to connect to the receiver. Once done, all outgoing packets are identified by sequence number and then are transferred in sequence until the end of the connection. The communication is closed after it reaches its maximum number of packets and then it drops any remaining packets in its buffer. 

What is UDP?

User Datagram Protocol (UDP) is a connectionless protocol used in computer networking. It works on the best-effort principle and is not normally used for transferring large blocks of data. This protocol works with destination port numbers which are only 16384 or 65535 by default. The communication can be temporarily stopped by both the sources and recipients at any time.

Difference between TCP and UDP

The biggest difference between TCP and UDP is that they cannot communicate with each other. This implies that you cannot use them together because they are based on different principles. Some other key differences between TCP and UDP are:

1) Packet loss: 

TCP detects packet loss and resends the lost packets, but UDP does not. When a UDP message reaches the receiver it is regarded as being permanently lost. This means that UDP messages are unreliable because they can be lost or duplicated in transit and there is no way to identify a lost message from its source.

2) Connection: 

TCP uses connection-oriented communication that establishes a virtual circuit before transferring data and closes it when all data is transferred. On the other hand, UDP uses connectionless communication in which a single datagram is sent without an establishment of the virtual circuit. This is how UDP works without needing to establish a virtual circuit 

3) Throughput: 

TCP has a throughput of around 500Kbps, while UDP has around 1Mbps. This means that you can transfer more data using TCP but you will get less throughput.

4) Error detection: 

TCP uses Transmission Control Block (TCB) for error detection and retransmission, but UDP does not use any error detection mechanism. Instead, UDP sends out datagrams as they come in from the network. There is no retransmission of missed datagrams or errors detected at the sender in case of UDP sending.

5) Security: 

TCP is a connection-oriented protocol that requires an exchange of sequence numbers, so it gives you data integrity and verification. However, in UDP the datagrams are sent without having any such verification or integrity checks.

6) Connection-oriented:

TCP involves establishment and release of connection, but UDP does not need such establishment or release. This implies that UDP has no maximum limit per datagram so a single host can use the whole bandwidth of its connection to the network interface card (NIC). In TCP, there is a maximum segment size per packet because it establishes a virtual circuit before sending data.

7) Error correction: 

In TCP the protocol has a sliding window algorithm that allows lost or corrupted data to be recovered. However, UDP does not have this mechanism so it simply discards any bad data without notifying the sender or receiver.

8) Connection establishment:

The creation of a connection is established through a handshake sequence by default. This means that both parties agree on communication rules before data transmission, and if one of them fails it is impossible to establish the connection. On the other hand, UDP does not do any handshake sequence but uses packet exchange as an initialization procedure for communication.

9) Transmission Control Block (TCB):

In TCP the datagrams are passed to the Transmission Control Block which is responsible for error control, resets, and retransmission. However, UDP does not use any such mechanism and there is no TCB in the case of UDP datagrams.

10) Reliability: 

In TCP reliable delivery is ensured through sequence numbers and acknowledgments, while in UDP each datagram is sent without any checks whether it has reached its destination or not. This mechanism prevents packet loss. However, in the case of a host getting two packets with the same destination address, both will reach the host because there is no protocol check of the packet that arrived first.

Conclusion:

TCP/IP is a well-known protocol used in networking. It has been developed under the OSI model. It helps transfer packets across the internet and between different LANs within an organization. The TCP/IP protocol provides a data transfer mechanism between systems that are connected to a network. This protocol is very effective as it allows connection-oriented communication. Over the internet, TCP/IP is used to establish virtual circuits.