UDP Full Form

UDP stands for User Datagram Protocol. It is a message-oriented communication protocol, used for communication channels and data paths. UDP uses a connectionless communication model with a minimum of initializing protocol mechanisms. The protocol is used extensively in applications requiring low-latency and loss tolerating connections, where the loss of some data isn’t much of a concern. 

The protocol is implemented on top of the IP (Internet Protocol), and is collectively called the UDP/IP Network Stack. UDP disowns certain features offered by other similar protocols, such as Handshaking(TLS/SSL) for initializing a connection, no acknowledgment for transmission progress, Data restructuring, etc. in order to offer a fast communication even on low bandwidth networks. Due to these characteristics of UDP it is implemented in VoIP, Web Streaming, Broadcasting, Gaming, etc. 

Characteristics

• Connection: Is connectionless protocol, therefore no Handshake is required to establish the connection
• No Acknowledgement: Data is sent unilaterally by the sender, and therefore no interaction of the recipient system is required (ex. sending acknowledgment about the received packets isn’t required).
• Less Overhead: Since no connection is required to establish the protocol, there are no ongoing connections to maintain. Which leads to less overhead.
• Orderless: The data may not arrive in order.
• Speed: Faster than other protocols of the same nature and requires fewer resources to function efficiently.  

Advantages

• Has a small header size of 8 bytes, due to which fewer data has to be transmitted
• Does not require a handshake before transmission of data
• Has no policy for intact data transfers, therefore lost packets are not re-sent hence reducing the congestion of recurrent requests
• UDP could be broadcast or multicast, so it allows a one-to-many protocol to exist
• Does not require an acknowledgment as a receipt for the data sent 

Disadvantages

• Does not provide any compensation for lost packets
• Does not offer any significant error detection mechanism, due to which the received data could be erroneous
• Does out of order delivery of data, due to which data has to be rearranged at the receiving end (which further requires some computation)
• Does not delay transmission if the network is congested, which could lead to packet loss or delay in delivery of the packet.