Several Important Modules Of The Distributed Switch Software Systems

The paper introduces the general situation of the Ethernet and Ethernet switch firstly, and the classes of Ethernet switch. Based on these contents, it gives the basic architecture of the switch, and the frame of main control board, interface board and the back board. The emphasis of the paper is the software system of the switch, especially the important models named out-band channel, board management system, hot plug-hot pull and hot backup. The out-band channel is a mechanism which combine software and hardware. The low level of it is 82559, which is a Ethernet switch chip, the upper one are two protocols. The paper demonstrates the device driver of 82559 in detail, then it introduces the two protocols----SRTP (Simple Reliable Transport Protocol) and UTP (unreliable transport protocol). At the end of this part, the paper tells us the synchronization invoke mechanism of SRTP and the usage of it. Board management system includes some sub-models, they are election, register, hot plug-hot pull, hot backup. In this part, the paper mainly discusses the election and the register. Election is an important process of distributed system, and the paper discusses how to implemented election arithmetic. The following two chapters are hot plug-hot pull (HPHP) and hot backup (HB). The first one is a good mechanism which can be used by the other models to process the plug and pull events, it guarantee maintainability and extensibility of the system. HB model is the core model of data backup, just like HPHP model, it also affords a well designed mechanism which can be used by other models in data backup process, and it ensure the standby control board can soon take over the job of the original active control board when the character of the two control boards is exchanged, so it ensures the redundancy. In the end, the paper makes a prospect about the future of the Ethernet switch.