TRANSMISSION OF FRAMED ATM CELL STREAMS OVER SATELLITE: A FIELD EXPERIMENT

摘要

In order to promote the use of satellite links in the European ATM Pilot Network, EUTELSAT has carried out laboratory tests and field trials of satellite transmission of 34 Mbit/s PDH-framed ATM cell streams, as specified in ITU-T G.804 and G.832. The effects of error bursts, introduced by the FEC schemes adopted in the 34 Mbit/s satellite modems, on the Physical Layer and the ATM layer have been measured and assessed. The results explicitly prove the viability of satellite links in ATM networks: no errors have been found when testing ATM transport over satellite links under nominal conditions. Tests carried out with deliberately degraded links demonstrate the accuracy of the calculation of the performance parameters, defined in ITU-T G.826, through the processing of the BIP-8, even in a bursty error environment. The tests have also confirmed that the probability of discarding ATM cells over links characterized by error bursts is orders of magnitude higher than over links with random errors, since the single-bit error correction capability of the HEC is ineffective in this situation. This paper advises on how to overcome this obstacle in an operational environment.