The Research And Optimization Of The ZESR Protocol Based On Ethernet Automatic Protection Technology

ABSTRACT:With the popularity of the Internet application and development, network’s bandwidth and stability as an important measure of morden computer network’s performance indicator, has become the focus of computer network’s performance inprovement. Convergence time refers to the time from the network topology changing to the information of changing synchronized to the router, and it is one of the most important indicators of the stability of the network. The convergence time of the initial spanning tree protocol, caused by the changing of the network topology, is about30s to50s, which is far away from achieving the requirement of the network now, and then the Rapid Spanning Tree Protocol and the Multi-instances Spanning Tree Protocol appeared. The recovery time of those protocols is difficult to contain less than Is, while the requirement of telecommunication Ethernet’s self-healing time is no more than50ms. So people begin to pay close attention to the EAPS, whose convergence time grade is millisecond. ZESR is based on EAPS Ethernet ring protection protocol and its convergence time can be within50ms. But ZESR is not yet perfect, there are a lot of loopholes and deficiencies in it.This article studied the protocols related spanning tree in the perspective of the stability of the network, which mainly analyzed and researched the ZESR protocol and found its serious problems on loop state detection and compatibility with MSTP. The paper is mainly divided into four parts:The first part mainly introduces the basic knowledge of the VLAN protocol, the development and characteristics of the spanning tree protocol, which contains the STP protocol RSTP protocol and MSTP protocol, and the principle of the EAPS.The second part researched and analyzed the business process and the handling process of the ZESR protocol, and put forward the ZESR’s two serious defects. The traditional Ethernet’s self-healing speed is too slow, which needs calculating in minutes or seconds, unable to meet the business requirement. ZESR-ZTE Ethernet Switch Ring network protection technology is improved based on the principle of EAPS rfc3619protocol, which makes the convergence time within50ms. However, after analysis, we found its serious problems on its loop state detection and compatibility with MSTP.The third part put forward Link-hello protocol as the solution of ZESR’s defection of loop state detection mode. It mainly described the design principle and the results of modifying.The last part of this article is the solution of the problem of excessive long convergence time, which caused by the incompatibility between ZESR and MSTP appeared in the testing. By making ZRSR forcefully sends a message mandatory to MSTP when network topology changes to achieve rapid convergence, and the results were tested.