Design And Implementation Of ISSU System Base On Stacking System

As the rapid development of network technology and sustained expanding of valueadded service, the steps of versions update on network communication equipmentsbecome more and more frequent.Online-upgrade and maintenance of Software versionhas become the most realistic demand to provide new features or modify thedefects,since users not only expect to obtain more services but also the service is alwaysrunning.In addition, the update of version about network equipments is executed onlyone every time, and the update version must be compatible.However, the stackingsystem based on virtual technology has been used widely. The traditional upgrademechanism may not only generate the servicesinterrupt with long time, but also lead tothe process of update out of control, resulting in the mix versions after upgrading.Therefore, this paper designed online-upgrade system without interruption of serviceabout a stack system on the Platform of H3C Company. The system can update allmembers under the unified control and support incompatible updates. Following by themain work:①This paper studies work-mechanismof the current stacking system, analysisdetailed the high reliability technology on stacking system, especially the theory of1: Nredundancy mode, fault detection and recovery mechanisms, simultaneously, introducesthe categories of current stacking system;②Studying ISSU(In-Service Software Upgrade) technology which describes thecomposition of the package, the decision-making process of upgrade mode, focuses onthe principle of serial upgrade modes and technology of None Stop Forwarding;③This paper introduces the platform and internal modules the author of this paperparticipates in on upgrade system. In the design section, this upgrade system focuses thedesign of several important internal module: The design about state machine controlmodule fully shows the upgrade process as well as state transition process of the entiresystem for users; Upgrade detection module checks the legality on user`s upgradecommand and upgraded version to guardant the reliability of upgrade.Decision controlmodule not only completes the control of policy process with upgrade equipments ateach stage of upgrade, but also optimizes all upgrade modes in order to ensure theservices will be not interrupted or o try to do business on the business interruptionimpact as low as possible, during the upgrade; Taking various schedule or non-schedule exceptions into account, the exception fallback module will fall back to a stable statebefore the upgrade once an exception occurs.④This article takes centralized stacking system of lateral stacking for instance,testing the incremental upgrade, soft reboot upgrade, compatible reboot upgrade,incompatible reboot upgrade. And the test results show that the upgrade system has metthe upgrade requirement of stacking system.