Local Area Networks are now being used to transport voice and video traffic together with traditional data traffic that they have already supported. And in the case of voice and video applications, not only is these is a need for more bandwidth, but there is also a need for guaranteed levels of receive because these applications are very sensitive to latency and delay.

Inverse multiplexing can be proved as technology that overcomes the bandwidth gap that exists between LAN and WAN. Inverse multiplexing is exactly the opposite of traditional multiplexing. In traditional multiplexing, multiple streams of data are combined into one single but larger data pipe, where as inverse multiplexing combines multiple circuits into single logical data pipe.


Asynchronous Transfer Mode (ATM) has compelling business as a WAN technology and is on a steep growth curve both in public carrier networks and in private organisations with requirements for networking video, voice and data traffic.


Inverse multiplexing over ATM (IMA) is a breakthrough standard that enables €Ëright sizing and right pricing of enterprise access solutions for organisations with low to mid range WAN traffic requirements and offers the benefits of ATM€„¢s quality of service and statistical bandwidth optimisation capabilities. IMA divides an aggregate stream ATM cells across multiple WAN links on a cell by cell basis and hence the name inverse-multiplexing. In combination with ATM, IMA simplifies and reduces WAN cost of ownership

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IMA (Inverse Multiplexing for ATM) is a standardized technology used to transport ATM traffic over a bundle of T1 or E1 cables, also known as IMA Group. This allows for gradual increase in line capacity, where implementing a high-capacity solution (e.g. optical fiber) is not deemed feasible. The maximum number of cables in an IMA Group is 32, bringing the total data rate to roughly 64 Mbit/second
for more..........
http://mtmnetPDF_FILES/IMA_White_Paper.pdf
http://ipmplsforumftp/pub/approved-specs/af-phy-0086.001.pdf