Research on performance of ethernet interface in network centric warfare

The concept of network centric warfare (NCW) and its character, high requirement of real-time synchronization are introduced. The distributed equal-node network architecture in NCW is presented. Based on theoretical analysis on ethernet interface performance, this paper presents that forwarding latency between ethernet interface devices is a key influence factor of real-time synchronization in NCW. Ethernet fundamental is briefly introduced. The model between a switch under test (SUT) and a smartbits card is presented and used for two interconnecting switches in NCW. On condition that ignoring the latency of connecting fiber or twisted pairs and processing latency of the smartbits test system, this paper presents that clock frequency tolerance (CFT) between a SUT and a smartbits card is a leading influence factor of forwarding latency of an ethernet switch. The formulae to calculate internal forwarding latency and forwarding latency caused by its CFT are deduced. Theoretical calculation on forwarding latency of an ethernet switch based on the given CFT and test time is implemented. Experimental study on primary forwarding latency and secondary forwarding latency is implemented and forwarding latency between the SUT and the smartbits card is measured, thus testifying the accuracy of the above theoretical analysis that the CFT is a key influence factor of forwarding latency. The measures to satisfy the needs of forwarding latency in NCW are presented.