Hard and Soft Real Time Based on Switched Ethernet

Abstract

As we know the Ethernet is based on IEEE 802.3 that can support high-speed in LANs. Unfortunately, this protocol has not supported real-time traffic yet. Therefore, several researches of supporting the real-time traffics on Ethernet are proposed. These approaches either implemented or proposed the real-time guarantees based on switch. Some of these approaches also supported both hard real-time and soft real-time guarantees. This paper represents an efficient switched Ethernet communication protocol for hard real-time and soft real-time traffics without any modification of the Ethernet hardware. Hard real-time communication management is handled by thin RT layer added between Ethernet protocol and TCP/IP Internet suite in the end-nodes. In addition, this paper also considers the guarantee to connect several switches into a system that can support hard real-time traffic. Moreover, this paper compares our suggested protocol to existing hard real-time protocols. The Ethernet switch adopts the EDF (earliest deadline first) that is a dynamic-priority scheduling algorithm to verify the scheduling feasibly and dispatch the coming packets. We also implement the AQC (active queue control) to solve the high network traffic load problem. Consequently, the QoS is improved.