• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.12B
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• pp.838-846
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• 2005

In this paper, we consider the following two issues for implementing the synchronous Ethernet systems. First, a synchronous Ethernet system employs a fixed size superframe which is divided into a synchronous period and an asynchronous one. We note that the starting point of a superframe is not deterministic when an ordinary data frame's transmission is overlapped the superframe boundary. This overlap may be a fatal drawback for strict jitter bounded applications. Circumventing the problem, we propose a frame fragmentation scheme to provide a zero jitter, and compare its delay performance with the hold scheme which also provides the zero jitter. We next concern that IEEE 802.3x pause frames cannot be promptly transmitted in a synchronous period, and thus asynchronous traffics may be dramatically get dropped at the input buffer of a switch. To handle the problem, we propose an efficient flow control by allowing the transmission of the pause frame in a synchronous period, and investigate the blocking probability of the asynchronous traffics by the simulation.