一种基于树的Whois文档解析方法*

从分析信息收集的关键问题入手,针对该类信息的表示特点,提出了一种基于树的文本解析策略.该方法对于解决半结构化的文本信息解析具有一定的普遍意义.     

Techniques for Determining the Geographic Location of IP Addresses in ISP Topology Measurement

A brief survey on the state-of-the-art research of determining geographic location of IP addresses is presented. The problem of determining the geographic location of routers in Internet Service Provider （ISP） topology measurement is discussed when there is inadequate information such as domain names that could be used. Nine empirical inference rules are provided, and they are respectively （1） rule of mutual inference, （2） rule of locality, （3） rule of ping-pong assignment, （4） rule of bounding from both sides, （5） rule of preferential exit deny, （6） rule of uureachable/timeout, （7） rule of relay hop assignment, （8） rule of following majority, and （9） rule of validity checking based on interface-finding. In totally 2,563 discovered router interfaces of a national ISP topology, only 6.4% of them can be located by their corresponding domain names. In contrast, after exercising these nine empirical inference rules, 38% of them have been located. Two methods have mainly been employed to evaluate the effectiveness of these inference rules. One is to compare the measured topology graph with the graph published by the corresponding ISP. The other is to contact the administrator of the corresponding ISP for the verification of IP address locations of some key routers. The conformity between the locations inferred by the rules and those determined by domain names as well as those determined by whois information is also examined. Experimental results show that these empirical inference rules play an important role in determining the geographic location of routers in ISP topology measurement.     

边界路由服务网关的分析与设计

本文通过分析目前多出口网络因边界路由器的功能局限而不能很好地解决内外相互访问的情况,提出边界路由服务网关的概念,并设计了边界路由服务网关的模型功能、体系结构与处理流程;最后通过实例验证了边界路由服务网关设计的正确性。     

X.500目录服务概述

Ｘ．５００目录服务协议的原理概述，与现存目录系统的比较，以及Ｘ．５００上前的发展情况。