ATM交换机信令适配层的设计与实现

The design and implementation of SALL in a ATM switch

在详细分析消化ＢＩＳＤＮⅠ系列建议基础上，文中简述了ＢＩＳＤＮ协议参考模型（ＢＩＳＤＮ／ＰＲＭ）和ＡＴＭ交换机组成与功能。在给出信令适配层（ＳＡＡＬ）分层结构的前提下，分析了各子层功能块的功能，较详细地介绍了特定服务面向连接协议ＳＳＣＯＰ（ＳｅｒｖｉｃｅＳｐｅｃｉｆｉｃＣｏｎｎｅｃｔｉｏｎＯｒｉｅｎｔｅｄＰｒｏｔｏｃｏｌ）的功能及其优点。在分析ＡＴＭ交换机中ＳＡＡＬ总体功能要求的基础上，设计并实现了ＳＡＡＬ软硬件，并且对ＳＡＡＬ功能的增强，ＣＲＣ－３２的软硬件计算，进程优先级的设置等关键技术进行了探讨，这对ＳＡＡＬ及其类似协议的实现有较大的意义。最后指出了ＳＡＡＬ在其它方面可能的应用。

Based on the international recommendation of BISDN,a brief introduction to its protocolreference model(BISDN/PRM)and ATM switch is given. The software and hardware ofSAAL(Signalling ATM Adaptation Layer)are designed and implemented after a detailedfunctional description and the analysis on the requirements of SALL-Finally,severat key is-sues such as function enhancement,fast calcutation of CRC-32(Cyclic Redundancy Check of32 bits),selection of different process priorities,are studied,which are of important signfi-cance for the implementation of SALL and relevant protocols.