大型企业网络设计及VPN技术的应用 the design of business network and application of VPN
摘 要 计算机的广泛应用和网络的普及改变着人们的生活，越来越多企业的业务也向网络转型，网络承载的业务种类越来越多，计算机网络已经逐渐成为了一种生产资料，网络的运行状况是否良好关系着企业的业务是否能正常运转。所以，构建一个具有良好可用性、稳定性、安全性、开放性 和扩展性的网络对于当今的企业来说尤为重要。本次设计以波司登集团为原型设计一个大型的企业内联网，实现集团总部和位于全国各地的分支机构的互联，在企业组网中运用专线组网技术和VPN组网的技术。本次设计主要实现以下三个任务。
分析企业网络背景和需求，设计出双星型的企业网络拓扑结构。遵循网络设计原则：连通性，可靠性，安全性，开放性，可扩展性等设计出波司登集团整体网络结构，实现集团总部和各个分支机构的互联，总部与大型分支机构的互联选择专线，总部跟规模较小的分支机构的互联使用VPN技术。
模拟整个网络，测试网络的连通性及可靠性、安全性等等的。搭建出设计好的网络机构，根据层次化配置方法将规划好的地址、路由生、生成树和VPN配置好，并对每一个要实现的功能进行测试。本次设计采用CiscoDynamips模拟器来实现仿真。
分析整个网络方案存在的不足，讨论现今企业网络的高端需求。本次设计能模拟的只是基础网络的部分，其实企业网络还存在许多基础网络之外的需求，比如上网行为管理，服务器的负载均衡，流量控制，网络优化等等，这些是凌驾于基础网络之上的，只有解决网络的连通性才会考虑这些问题。
关键词：OSPF协议； STP协议； IPSEC VPN；GRE VPN
Abstract
The widely use of computers and the popularization of the Internet changing our lives ，more and more business transform to network ，more kinds of business loading upon the network，The computer network has gradually become a kind of production material ， Whether the operation status of the network is well relations to business of the enterprise.So, it is very important to construct a good usability, stability, security, openness and expansive network for today's enterprise .This design is base on BoSiDeng and design a large enterprise's Intranet, achieve interconnected of the headquarter of Enterprise and branches which located in other cities in the country, using line technology and VPN network technology.
Analysis the requirements of enterprise networks, and design the whole topological graph of enterprise networks. We design the whole network abiding by the network design principle：connectivity, reliability, security, openness, expandability and so on ,and realize the connection between the group headquarters and affiliated group combine with practical situation. The headquarter and umbrella affiliated group is connected by special line, and connected with small-scale affiliated group by VPN technology to cost saving.
detailed IP address planning and VLAN planning is designed for the whole network.
Simulation the whole network by simulator, and proceed the test and data analysis. Engineering IP address partition is contributing to proceed route summary, and route manager. Scientific VLAN partition can divide departments with different duty, realize business partition, and effectively reduce the boundary of wide-area domain .CiscoDynamips simulator is used for realize simulate in this design process. Analysis the shortage exist in the whole system, and discuss the requirement of current enterprise network .Just the fundamental part of the network is simulated in this design, many equipments out of the fundamental network exists in the enterprise network in fact, such as Employee Internet Management, Load Balancing of the server, bandwidth management , Network Optimization and so on. All of these is outmatch the fundamental network, but will consider after the connection is solved.
Keywords ：OSPF protocol；STP protocol； IPSEC VPN；GRE VPN
引言 1
1. 绪论 2
1.1 项目背景 2
1.2 需求分析 3
1.3 主要技术 4
1.3.1DHCP技术 4
1.3.2HSRP（Hot Standby Route Protocol） 5
1.3.3生成树协议 6
1.3.4OSPF 协议 6
1.3.5 VPN 介绍 8
1.3.6防火墙技术 11
2. 工程设计 12
2.1 仿真拓扑图说明 14
3. 工程仿真与测试 14
3.1 IP地址、VLAN 规划 14
3.2 工程拓扑机构的搭建 15
3.3 基础信息配置 15
3.4 VLAN 的配置和IP地址的配置 16
3.5 生成树配置和HSRP主备网关配置 17
3.6 OSPF配置与测试 19
3.6.1OSPF邻居状态 19
3.6.2路由备份与切换的设计 20
3.7 VPN配置与测试 22
3.7.1NAT的配置 22
3.8 本章小结 24
4. 方案不足和现今网络高端需求分析 25
4.1 方案的不足 25
4.2 现今各行业网络高端需求 25
4.2.1管理审计的需求 25
4.2.2服务器负载均衡和链路负载均衡需求 26
4.2.3流量控制需求 27
4.2.4传输加速、数据优化 27
4.2.5应用性能监控 27
4.2.6商业
