Title : Necessity O F a N F E C S C Heme for Atm Networks

This contribution discusses the bene ts of a cell level forward error correction FEC scheme in the AAL An FEC scheme will bene t real time needs of multimedia applications as well as reliable data communications An ATM network performance degrades rapidly with increasing cell loss or the bit error rate BER of the medium The achievable throughput for reliable services also deteriorates with increasing packet or frame size Further when reliable multicast service is used the packet throughput seriously degrades with the number of receivers An AAL level FEC scheme would improve the end to end QoS in all these cases FEC schemes would be very bene cial in cases where retransmissions by a higher layer protocol lead to low QoS and an ine cient use of network resources or where delay requirements preclude the use of retransmissions This contribution therefore proposes that the SA A specify an AAL level FEC scheme as an optional SSCS function