ARCNET与ETHERNET互连网桥设计

The Design of Bridge between ARCNET and ETHERNET

网桥是一种在链路层实现局域网互连的存储转发设备，网桥分透明网桥和源选径网桥两种，本文采用透明网桥算法实现了ＡＲＣＮＥＴ与ＥＴＨＥＲＮＥＴ的互连。为了使网桥软件具有良好的可移植性，在设计上采用模块化结构，本软件包含ＡＲＣ－ＭＡＣ，ＥＴＨ－ＭＡＣ和ＢＫＥＲＮＡＬ三个模块，其中ＭＡＣ模块负责对网络硬件的操作，并为网桥核心模块提供统一的接口界面，通过ＭＡＣ模块替换，可实现ＡＲＣＮＥＴ－ＥＴＨＥＲＮＥＴ和ＥＴＨＥＲＮＥＴ－ＥＴＨＥＲＮＥＴ互连。由于ＡＲ－ＣＮＥＴ帧格式及ＡＲＣＮＥＴ硬件设计上的特点，所以在透明同桥设计时需要考虑ＡＲＣＮＥＴ的特殊性，本网桥在ＡＲＣ－ＭＡＣ模块中进行了相应处现，从而实现了ＡＲＣＮＥＴ与ＥＴＨＥＲＮＥＴ之间的透明互连。

Network bridge is an internet connecting device which works in the data link layer for storing and resending. There are two kinds of network bridge:the transparent bridge and source selecting path bridge. In this paper,the former is used to connect the ARCNET and the ETHERNET. To bring about good transplantability of the bridge software,we use a modulized structure, in which are involved three modules: the ARC MAC, the ETH MAC, and the BKERNAL. The MAC moduls are used to operate the network hardware, and to give the unique interface to the hemal rnodul of the bridge. Interconnection of ARCNET-ETHERNET and ETHERNET-ETHERNET can be brought about by the replacement of MAC modul. In designing the transparent bridge, special consideration should be given to the ARCNET for its particularities in its frame format and in the hardware design. Transparent interconnection is brought about between the ARCNET and the ETHERNET by corresponding treatment ofARC MAC modules.