CCNA新版PPT 第15章 ISDN.ppt

* 上图表明2600和3600系列的一些型号的设备可以配置的拨号端口数目 异步：表明选择的是不带内置Modem的异步或同步/异步网络模块(一个模块上最多32个异步口 模拟Modem：表明选择的是内置模拟Modem的网络模块(一个模块上最多16个模拟Modem) 数字Modem：表明选择的是内置数字Modem的网络模块(一个模块上最多30个数字Modem) * Many companies have begun to use the Internet to provide network access to business partners, employees, and even remote branch offices. With support for data encryption, tunneling, QoS, and user authentication, the Cisco 2600 provides the ideal solution for connecting to both dial and Dedicated Virtual Private Networks or VPNs. The Cisco 2600 provides the processing power necessary to terminate Layer 2 Forwarding (L2F) and Layer 2 Tunneling Protocol (L2TP) or IPSec sessions, allowing a customer to outsource dial services to a service provider while maintaining control of security and reducing costs associated with maintaining a large bank of dial in modems. VPNs can be based either on IP or other protocols (such as IPX.) When used with the Cisco IOS Firewall feature set, the Cisco 2600 and 3600 series provide enhanced security for VPN access. For maximum strength encryption, the Cisco 2600 supports 3DES Ipsec encryption (triple 56 bit or 168 bit encryption) which is also available for most Cisco IOS supported platforms providing a scaled end to end solution from small to corporate to backbone deployments. * 综合业务数字网 CCNA经典课件 网络技术交流QQ群：196267207 （Intergrated Services Digital Network,ISDN) 一 、ISDN的起源和优点 ISDN起源于1968年当时人们预测它将访问集成到广泛的服务的范围（语音、网络互联、报文交换和有线电视） ISDN基于模拟通信的优点1、连接建立极快2、比租用线路价格低 3、比模拟线路的传输速度更快 什么是 ISDN Providernetwork Digital PBX Small office Home office ISDN 能够提供声音、视频、数据等传输服务 Telecommuter Central site ISDN的两种服务方式 ISDN服务根据不同的信道数目分为： 1、BRI(Basi Rate Interface) 应用于小型企业或家庭 典型的ISDN BRI服务提供两个B信道和一个D信道 （2B+D） 2、主速率接口（PRI,Primary Rate Interface）应用于大型企业 [北美和日本]ISDN PRI提供（23B+D）信道 ，速率可达1.544Mbps [欧洲]提供的ISDN PRI提供（30B+D）信道， 速率可达2.048Mbps T1:1.544Mb/s E1:2.048Mb/s BRI 和 PRI 是ISDN的两种常见访问方式 Channel Mostly Used for B 传递所有的语音/数据通信(HDLC, PPP) Capacity 64 kbps D