Accurate estimation of capacities and cross-traffic of all links in a path using ICMP timestamps

The estimation of the link capacity and its available bandwidth in an end-to-end path is crucial for network management, admission control and flow control for adaptive applications. This paper introduces an estimation mechanism able to accurately estimate the available bandwidth of all links in an end-to-end path, through its capacity and cross-traffic estimation. The estimation procedures resort to the dispersions of packet pairs and trains using the concepts of ICMP Timestamp and Traceroute that, efficiently used together, enable the measurement of the dispersions in all links in the path. These mechanisms were evaluated through simulation experiments, where we analyzed the influence of the several network parameters on each estimation mechanism. The results show that these estimation methods are able to accurately estimate both the capacity and the cross-traffic of all links in a path with moderate length and with low overhead.     

IPv6在QoS上的三项重要改进

本文主要分析了IPv6相对于IPv4在QoS上所做的基本报头、ICMP控制机制及基本报头中的QoS元素三项改进,从而为有效支持QoS提供理论支持。     

混合SVM结合信息熵检测ICMP隐通道*

攻击者可以将生成的任意信息隐藏在ICMP的有效负载中传递出去,构成了ICMP负载隐通道。在分析ICMP数据流熵标准差和熵值分布特性的基础上,提出了基于信息熵的样本集缩减策略。为提高采用标准支持向量机(SVM)的学习能力与推广能力,建立了若干选取规则,构造出一种有效的混合核函数。最后采用混合SVM结合信息熵的方法检测ICMP隐通道,取得了较快的分类速度和较高的检测率。实验结果表明,采用混合SVM结合信息熵检测ICMP隐通道的方法,是有效的、可行的。     

Development and Verification of Simulation Model Based on Real MANET Experiments for Transport Layer Protocols （UDP and TCP）

There is a lack of appropriate guidelines for realistic user traces, mobility models, routing protocols, considerations of real-life challenges, etc. for general-purpose mobile ad hoc networks (MANET). In this paper, four laptops are used in an open field environment in four scenarios to evaluate the performances of Internet control message protocol (ICMP) based ping and transmission control protocol (TCP) based streaming video applications using optimised link state routing (OLSR) implementation in an IEEE 802.11g wireless network. Corresponding simulations are developed in Network Simulator ns-2 by setting simulation parameters according to the real experiments. Difficulties faced to regenerate real-life scenarios have been discussed and the gaps between reality and simulation are identified. A setup guideline to produce realistic simulation results has been established.     

网络拓扑自动发现系统设计与实现

摘要：设计基于SNMP和其它协议的网络拓扑发现算法,实现三层交换机和路由器为网关的网络拓扑的快速发现,尽可能地发现完整的网络,且对网络带来的额外负栽和开销尽可能小。     

浅谈博州气象局网络实时监控系统的设计

随着网络技术的迅猛发展,对网络运行状态的实时监控显得十分重要。通过综合分析我局整个网络拓扑结构,开发了基于delphi语言环境的实时网络监控系统,介绍了该系统的实现必要性、功能、设计原理和实现流程。投入业务应用的实践表明,该系统实用性强,对网络系统实时监控效果很好,大大提高了网络的有效性和可靠性。     

NetBsd操作系统网络部分ICMP缺陷的修正

NetBsd是Unix的变种,作为控制部分的操作系统广泛应用于网络设备中,该文报告在使用过程中发现的网络部分的缺陷及其修正方法。     

对Ping命令的代码级分析研究

Ping是一个经常被使用在TCP/IP网络的检测工具,一般网络错误都可以用Ping检测出来.通过对FreeBSD系统下的Ping源代码的详细分析,说明Ping利用了什么网络原理和协议,并且利用哪些具体网络编程采实现各种功能的,也说明了Ping一般检测网络的结果是怎么实现的.     

基于IP协议TTL的网络拓扑搜索算法

常用的网络拓扑搜索算法,并对一种基于IP协议TTL的网络拓扑搜索算法进行了详细的介绍.     

一种基于ICMP报文的IPv6隧道机制

ＩＰｖ６研究中,一个重要的问题是如何实现从ＩＰｖ６的迁移。目前的自动隧道机制都是依赖ＩＰｖ４－兼容的ＩＰｖ６地址。本文提出了一种基于ＩＣＭＰ报文的迁移机制,能够对任意配置的ＩＰｖ６／Ｉｐｖ４,节点实现自动隧道配置。