From the above discussion, UDP looks pretty useless, right?
• UDP is a slimmer protocol: its protocol header is fixed at 8 bytes, whereas TCP’s is 20 bytes at minimum and can be more. • UDP has no congestion control and no data coalescing. This eliminates the delays caused by the delayed ACK and Nagle algorithms. (This is also a disadvantage in many situations, of course.) • There is less code in the UDP section of the stack than the TCP section. This means that there is less latency between a packet arriving at the network card and being delivered to the application. • Only UDP packets can be broadcast or multicast. This makes UDP good for applications where timeliness and control is more important than reliability. Also, some applications are inherently tolerant of UDP problems. You have likely experienced blips, skips and stutters in streaming media programs: these are due to lost, corrupted or duplicated UDP frames. Be careful not to let UDP’s advantages blind you to its bad points: too many application writers have started with UDP, and th
