Inverse multiplexer

A high data rate signal is inverse multiplexed over multiple slower links, then recombined

Aninverse multiplexer(often abbreviated toinverse MUXorIMUX) allows adata streamto be broken into multiple lower data ratecommunication links.An inverse multiplexer differs from ademultiplexerbecause the multiple output streams from the former stay inter-related, whereas those from the latter are unrelated. An inverse multiplexer is the opposite of amultiplexerin that it divides one high-speed link into multiple low-speed links, whereas a multiplexer combines multiple low-speed links into one high-speed link.

This provides an end to end connection of several times the data rate available on each of the low rate data links. Note that, as with multiplexers, links are often used in bi-directional pairs and, at either end of the link, an inverse multiplexer will be combined with its reverse (an inverse demultiplexer) and still be called aninverse MUX.

Inverse multiplexers are used, for example, to combine a number ofISDNchannels together into one high rate circuit, where a higher rate connection than is available from a singleISDNconnection is needed. This is typically useful in areas where higher rate circuits are not available.

An alternative to an inverse multiplexer is to use separate links and load sharing of data between them. In the case of IP, network packets could be sent inround-robinmode between each separate link. Advantages of using inverse multiple xing over separate links include:

• Lower linklatency(one single packet can be spread across all links)
• Fairerload balancing
• Network simplicity (nonetwork switchneeded between boxes with high-speedinterfaces)

A simple analogy to transport can help explain the distinction between multiple xing and inverse multiple xing. When small cargoes such aspencilsare shipped overseas, they are generally not carried one at a time, but are assembled into small boxes, which are grouped into larger cartons, which go intointermodal containers,which are packed onto acontainer ship.Each step is analogous to a multiple xing process. Conversely a large cargo, for example instructure relocation,may be disassembled for carriage on multiple vehicles and reassembled at the destination. This is analogous to inverse multiple xing.

See also

• Bonding protocol
• Divide-and-conquer algorithm
• Inverse Multiple xing for ATM
• Link aggregation
• Multiplexer
• Multilink PPP
• Virtual concatenation