The maximum transmission unit, or MTU, is the single largest frame or packet of data that can be transmitted across a network. The exact nature of the maximum transmission unit will be determined by the configuration of the network and what type of protocols is in place for the transmission of data. Generally, a maximum transmission unit is composed of eight-bit bytes of information.
The size of the frame or packet is very important to the process of transmitting data through any network. For this reason, there are usually specific rules that govern the size of data packets that can be transmitted without creating some sort of bottleneck within the network. In the case of the Internet, a set of standards referred to as the Transmission Control Protocol is utilized to define what constitutes a functional size of data packet.
When transmitting information, the size of the maximum transmission unit is very important. In the event that the packet or frame is too large, the end result could be a router that is unable to process the packet properly and the data transmission will fail, or the router will go into a series of continual attempts to process the packet. This can lead to failure of the router to handle other transmissions.
At the same time, if the maximum transmission unit is rather small, that leaves more room for headers and other types of overhead that may be processed as part of the data packet. This can also mean more that it is necessary to send and process more acknowledgements as well. While a smaller packet is less likely to cause a bottleneck, it does leave room for resources to be wasted.
MTUs have been around for a number of years. As technology has continued to progress, the desirable size of a given maximum transmission unit has grown accordingly. Operating systems located on hard drives usually are preset with an MTU range that is in accordance with most common applications. Generally, the setting reflects a general range, as what is standard for one type of network may be high or low for another network. Internet service providers tend to make recommendations about settings for MTU reception as well, based on the type of connectivity that is in place and the operating system employed by the end user.
