OSI/MMS系统中ASN.1编/解码器的设计与实现

DESIGN AND IMPLEMENTATION OF AN ASN.1 ENCODER/DECODER IN THE OSI/MMS SYSTEM

ＡＳＮ．１是一种标准的抽象语法定义描述语言，它提供了定义复杂数据类型以及确定这些数据类型值的方法．许多ＯＳＩ应用协议标准都采用ＡＳＮ．１作为数据结构定义描述工具，尤其用来定义各种应用协议数据单元（ＡＰＤＵ）的结构．本文首先介绍ＡＳＮ．１数据类型和基本编码规则，接着详细讨论ＭＭＳ通信系统中ＡＳＮ．１编／解码器的设计与实现．此编／解码器用于ＭＭＳ协议数据单元（ＰＤＵ）的ＡＳＮ．１抽象语法和传送语法之间的转换，以实现ＭＭＳ在异种机、异种操作系统环境下的互操作．最后。

ASN.1 is a standard definition and description language for abstract syntaxes.It offers a method of defining complex data types and specifying the values of these data types.ASN.1 is used as a means of defining and describing data structures by many OSI application standards,especially for defining the structures of various Application Protocol Data Units(APDU).ASN.1 data types and basic encoding rules are introduced in this paper.The design and implementation of ASN.1 encoder/decoder in an MMS messaging system are discussed in detail.This encoder/decoder is used for the conversion between ASN.1 abstract syntax and transfer syntax of MMS Protocol Data Units(PDU),helping to achieve MMS interoperability in a different machines and different operating systems environment.Finally,concrete improvement methods of raising encoding/decoding efficiency are also presented.