互联网应用技术互联网技术Internet体系结构和-Read.PPT

互联网应用技术第二节 互联网技术第六章 Internet地址 冯健文 Fengjw@ 内容安排 Internet地址结构 Internet地址类型 Internet地址的缺陷 什么是地址 Internet技术目的是统一不同的物理技术，首要解决问题就是地址的统一。 地址的作用：标识对象在哪里 两种地址： 1、无位置地址：如局域网 2、有位置地址：如广域网，Internet ARPANET地址 主机地址如（P,N），P代表分组交换节点（PSN）号，N代表与该PSN相连的某主机号。 这是一种层次型的地址结构 物理地址与Internet地址 物理地址的特点： 1、物理网络不同，物理地址也不同； 2、同一类型不同的网络上可能有相同的物理地址； Internet采用在物理地址上建立IP地址，来实现地址的统一。 IP地址=网络号+主机号 IP地址层次保证了： IP地址的两层结构设计使得寻径很有效 地址的唯一性。虽然网络号分配必须全球一致，但主机号可本地分配，不需全球一致 IP 地址编码 IP地址编码 IP 地址类型 Class A: Class B: Class C: Class D: For Multicast Class E: For Research IP Address Bit Patterns IP Address Bit Patterns IP Address Bit Patterns Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes Exercise: IP Address Classes IP地址标识的是网络接口，而非计算机。 路由器连接多个网络，因此路由器有多个IP地址，一个IP地址标识一个网络接口。 多穴主机：一个主机连接多个网络，没有路由的功能，增加灵活性和可靠性。 Internet地址的缺陷 缺陷1：C类向B类地址升级时，会“休克” 缺陷2：进行多穴主机的分组路径跟使用的地址相关。 缺陷3：对多穴主机的寻径，不能只知道一个地址。 网络1 网络3 网络2 G1 G2 H1 The IP address is 32 bits in length and is made up of two parts: Host number Network number The address format is known as dotted decimal notation. Example address: 0 Each bit in the octet has a binary weight, such as (128,...4,2,1). The minimum value for an octet is 0; contains all 0s. The maximum value for an octet is 255; contains all 1s. The allocation of addresses is managed by a central authority. Network numbers are administered by the Internet Network Information Center (InterNIC). The NIC also is the main RFC repository. The IP address is 32 bits in length and is made up of two parts: Host number Network number The address format is known as dotted decimal notation. Example address: 0 Each bit in the octet has a binary weight, such as (128,...4,2,1). The minimum value for an octet is 0; contains all 0s. The maximum