Simple Type Eos System Design And Its Key Technology

The study of the Ethernet Over SDH (EOS ) system design and the key technique is described in this paper. There are some problems in EOS protocol, which are high implementation complexity and poor utilizing efficiency of SDH network bandwidths, etc. To solve these problems, a simple, fast and high efficiency protocol implementing method is proposed in this paper. This method effectively reduces PPP over SDH protocol implementation complexity by passing over the process of parameters negotiation and PPP link management produce. This method uses HDLC frame format to encapsulate Ethernet MAC frame directly and omits the padding field in PPP frame format. The system using this method can be compatible with other EOS equipments using PPP Over SDH protocol. It has higher efficiency of encapsulation. This system can communicate with other equipments, because this method places a full HDLC frame into one independence SDH channel. In order to resolve the insufficiency of network bandwidths, a flow control algorithm suiting EOS system is proposed in this paper. This algorithm is suitable to the condition that Ethernet data bandwidths are larger than SDH ones. It integrates the method of buffers assignment related with bandwidths and packets discarding to improve the utilizing efficiency of SDH bandwidths. Based on the analysis of the characteristic of Ethernet data flow and the efficiency of SDH transmitting system, the port speed selection rules and the method of buffers assignment related with bandwidths are proposed. Buffers are configured as blocks and counted as frame unit, so adress canculates simply. It not only drops the complexities and difficulties of algorithm implementation, but also implements the static configuration of bandwidth. Based on studying of above these key techniques, we develop the TransmartEOS system applied in SDH 2.5G/622M system. The results show that the EOS protocole, theiiflow control algorithm, port speed selection rules and the static configuration of bandwidth work well. With the testing results of TransmartEOS system, it is obviouse that these methods and algorithms have higher efficiency, faster speed and simpler implement. It is very suit to implement EOS system fastly. The TransmartEOS system has been applied now.