The UMG8900 supports the inverse multiplexing over  ATM (IMA) networking over the Iu interface. That is, the  A TM-basednetworking over the Iu interface supports the ATM over E1/T1 function.

 

This feature supports the  A TMover E1 interface, which improves the networking flexibility of the UMG8900.

 

The UMG8900 supports the IMA function, which improves the networking flexibility of the UMG8900. IMA refers to multiplexingof high-speed  ATM cell streams over low-speed links.  At the transmitting end, the  A TM cell stream on a high-speed transmission link is inversely multiplexed on multiple low-speed transmission links, and then is transmitted.  At the receiving end, the cell streams on the low-speed transmission links are converged as a
high-speed  ATM cell stream. The E1 and T1 links are low-speed links on the UMG8900.

The fractional  ATM function is mainly applied in networks wherebandwidths are precious. Through this function, the  ATM IMA link with the variablebandwidth of Nx 64 kbit/s canbe configured. That is, a fractional  ATM link occupies N timeslotsof an E1 interface and the bandwidthof each timeslot is 64 kbit/s.

The differences among the IMA link, UNI link, and fractional  ATM link are as follows:

 

The IMA layer is located between the physical layer and the ATM layer in the  ATM protocol model. The IMA layer demultiplexes ATM cells for transmission in multiple low-speed physical media, or multiplexes the signals in low-speed physical media to high-speed  ATM cells.

The transmission over a UNI link means the transparent transmission of data over an E1/T1 link, and the data is not processed by the IMA protocol. The transmission over a fractional  A TM link also means the transmission of data over an E1/T1 link, but it is different from the transmissionover a UNI link. The UNI link occupies all the timeslots except the timeslots used for synchronization and signaling transferof the E1/T1 link; the fractional  A TM link uses the timeslots specified by the user to transmit user data.

The IMA link canbe applied in inter-of fice interworking where a large numberof users and heavy traf fic are present. The UNI link and fractional  ATM link canbe applied in intra-of fice interworking where the numberof users is small and the traffic is light.

 

what does it mean by high-speed  ATM cell stream?

The IMA link canbe applied in inter-of fice interworking where a large numberof users and heavy traf fic are present. this will help for large subs operator.

Thanks to share the important topics.

What is IMA link?

The IMA layer demultiplexes ATM cells for transmission in multiple low-speed physical media, or multiplexes the signals in low-speed physical media to high-speed  ATM cells.

 

How is it happended? What is the technique?

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