TCPIP协议族期末总复习

TCP/IP协议族期末总复习 第一章 Protocols：语法，语义，同步（三要素） Standards：事实标准，法律标准 Internet Society (ISOC)，因特网协会 Internet Architecture Board (IAB)，因特网体系结构研究委员会 Internet Engineering Task Force (IETF)，因特网 工程 路基工程安全技术交底工程项目施工成本控制工程量增项单年度零星工程技术标正投影法基本原理 部 Internet Research Task Force (IRTF)，因特网研究部 Internet Assigned Numbers Authority (IANA)，因特网赋号管理局 Names and Numbers (ICANN)，名字与号码指派公司 Network Information Center (NIC)，网络信息中心 ISO:国际标准化组织 ITU-T：国际电信联盟-电信标准部 ANSI：美国国家标准化局 IEEE：电气和电子工程师学会 EIA：电子工业协会 Figure 1.4    Internet administration Figure 1.3    Requirement levels of an RFC 第二章 ISO is the organization. 国际标准化组织(ISO) 开放系统互连 (OSI) OSI is the model Figure 2.1    The OSI model The physical layer is responsible for the movement of individual bits from one hop (node) to the next. The data link layer is responsible for moving frames from one hop (node) to the next. The network layer is responsible for the delivery of individual packets from the source host to the destination host. Figure 2.10    Reliable process-to-process delivery of a message The transport layer is responsible for the delivery of a message from one process to another. 会话层负责对话的控制和同步 应用层负责向用户提供服务 Figure 2.14  Summary of layers* Figure 2.17    Relationship of layers and addresses in TCP/IP 例 题 快递公司问题件快递公司问题件货款处理关于圆的周长面积重点题型关于解方程组的题及答案关于南海问题 ：（不是绿色的，仅供参考）参照课本31--34页 Example 1 In Figure 2.18 a node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link. At the data link level this frame contains physical (link) addresses in the header. These are the only addresses needed. The rest of the header contains other information needed at this level. The trailer usually contains extra bits needed for error detection. Example 2 As we will see in Chapter 3, most local area networks use a 48-bit (6 bytes) physical address written as 12 hexadecimal digits, with every 2 bytes separated by a colon as shown below: 07:01:02:01:2C:4B A 6-byte (12 hexadecimal digits) physical address. Example 3 In Figure 2.19 we want to send data from a node with network address A and physical address 10, located on one LAN, to a node with a network address P and physical address 95, located on another LAN. Because the two devices are located on different networks, we cannot use link addresses only; the link addresses have only local jurisdiction. What we need here are universal addresses that can pass through the LAN boundaries. The network (logical) addresses have this characteristic. Example 3 (Continued) The packet at the network layer contains the logical addresses, which remain the same from the original source to the final destination (A and P, respectively, in the figure). They will not change when we go from network to network. However, the physical addresses will change as the packet moves from one network to another. The boxes labeled routers are internetworking devices, which we will discuss in Chapter 3. Example 4 As we will see in Chapter 4, an Internet address (in IPv4) is 32 bits in length, normally written as four decimal numbers, with each number representing 1 byte. The numbers are separated by a dot. Below is an example of such an address.          132.24.75.9 An internet address in IPv4 in decimal numbers Example 5 Figure 2.20 shows an example of transport layer communication. Data coming from the upperlayers have port addresses j and k ( j is the address of the sending process, and k is the address of the receiving process). Since the data size is larger than the network layer can handle, the data are split into two packets, each packet retaining the service-point addresses ( j and k). Then in the network layer, network addresses (A and P) are added to each packet. Example 5 (Continued) The packets can travel on different paths and arrive at the destination either in order or out of order. The two packets are delivered to the destination transport layer, which is responsible for removing the network layer headers and combining the two pieces of data for delivery to the upper layers. Example 6 As we will see in Chapters 11, 12, and 13, a port address is a 16-bit address represented by one decimal number as shown below.                  753 A 16-bit port address represented as one single number. 第三章 Figure 3.1    Internet model local area network (LAN) 局域网 Figure 3.2    CSMA/CD 带碰撞检测的载波侦听多点接入 Three factors  of  CSMA/CD: l the minumum frame length l The data transmission rate l The collision domain The time the station needs to wait to be sure that there is no data on the line is the minimum frame length divided by the transmission rate( the time required to send out the minimum frame length).This time is proportional to the time needed for the first bit to travel the maximum network distance(collision domain).