Understanding how data are sent, received and translated is a major part of the Internet's architecture. It is a highly technical field that is dedicated to preventing data loss and, just as important, data fragmentation. Speed is important, but so is accuracy. In general, this aspect of data communication is about translating data from the physical element of the computing world to the “soft” or electronic elements of that world. All forms of data transmission and translation are about preserving the integrity of the data transmitted.


In the computer networking world, “layers” play a very important part in grasping the physical and non-physical aspects of data transmission. “Layers” represent elements in this process. For example, layer 1 is usually the physical aspect of the computing system, its hardware. Layer two is the translation of data into your computer from a network. Level three is your computer's IP address and other forms of specific information, while level 4 is the transportation of data throughout the network. The point is, while this description is radically simplified, each layer represents one part of the process of data transmission and decoding within a network.

Logical Link Control

LLC is a slightly older, slower network protocol. It is a method of sending and receiving data throughout a computer network. It is a more complex “packet” of data in that it must specify the nature of the translation process. It is designed to maximize the accuracy of the data transferred, though it is slower than its main rival and harder to maintain since it contains more actual information than VC-MUX.

Virtual Circuit Multiplexing

As its name suggests, VC-MUX can handle more data quicker than LLC. The big difference here is the “agreement” among the systems on any specific network. This means that all systems must agree on the specific nature of the data translation method. In practice, this means that there is less coding among the various “data packets” the system is sending to the hardware units in the system. Put differently, the VC-MUX can send many different kinds of data under a single protocol, so long as all the units in the system agree on what that is.


As of 2011, most computing networks use a combination of the two forms of data transport, depending on the clients and the nature of the network. Since VC-MUX requires “agreement” among the computers in the system, it is more expensive. It requires the Internet service provider, for example, to pre-program all their DSL boxes to receive one and only one encoding and decoding method. On the other hand, a LLC method will program this method in the data itself. This makes the coordination in a network easier, as well as adding to its flexibility. The extra programming hours amount to almost nothing in terms of basic expense, but the hardware uniformity for the VC-MUX does cost a bit extra. Ultimately, VC-MUX turns out to be the more accurate method, since it has fewer bits of data to work with. Since LLC is more complex, data errors and fragmentation are more common.

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