用P2P技术改进网格信息服务

本文根据网格资源信息的特点阐述了由高度分布式的信息提供者和集合目录组成的网格信息服务基本框架。并分析了它的基础LDAP（Lightweight Directory Access Protocol）协议，指出LDAP目录本质是一种分布式的数据库。由于网格信息系统中LDAP目录信息树的动态刷新与复制的频繁发生，我们已提出用环形扩展和线形扩展策略来大幅度提高系统效率；在此基础上，本文进一步提出了文件分块复制法的思想把LDAP数据库文件分成若干块，在多个LDAP服务器端点间并行复制，最后实践证明，它大幅度提高了以LDAP目录分布式数据库为基础与核心的网格信息服务系统的并行效率。

Improved Grid Information Service Using the Technology of P2P

The infrastructure of grid information service constituted with highly distributed information providers and aggregate directory is brought forward on the basis of the characteristic of grid information resources in the paper.The Grid Information Protocol (GRIP) makes both discovery and enquiry for entity information repeatedly by sorts of flexi- ble measures and the Grid Registration Protocol (GRRP) keeps the resources available by the continuous and periodic updating from the information providers in the infrastructure.The Lightweight Directory Access Protocol (LDAP) that is one of the base protocols is also analyzed.It is put forward that LDAP is a distributed database that has the charac- teristic of spanning flat and accessing according to the register.The server-to-server communication mode of LDAP de- fines how to share the LDAP directory and how to update and replicate the information between servers.The dynamic updating and replication of LDAP directory tree would happen frequently for grid information system is distributed widely,highly fault-tolerant,dynamic and diversiform.It has been put forward that the strategy of annular spread and line-form spread can boost the efficiency of grid information service system that regards the distributed database of LDAP as the foundation and core.What's more,we use the viewpoint of file parted replication to divide the LDAP da- tabase file into several blocks that are replicated parallel between LDAP sever points then.In such a way,the system efficiency of parallel processing can be boosted by margin.And based on the idea forenamed,we put forward the tech- nique infrastructure and block arithmetic,both of which are proved to be available in improving the system efficiency.