chapter笔记.docVIP

1. Cisco 也推出了面向大型网络的 IGRP（内部网关路由协议）和 EIGRP（增强型 IGRP)协议。 此外，不同网际网络之间的互联也提出对网间路由的需求。现在，各 ISP 之间以及 ISP 与其大型专有客户之间采用 BGP（边界网关路由）协议来交换路由信息。 2. dynamic routing protocols require less administrative overhead. However, the expense of using dynamic routing protocols is dedicating part of a routers resources for protocol operation including CPU time and network link bandwidth. 3. A routing protocol is a set of processes, algorithms, and messages that are used to exchange routing information and populate the routing table with the routing protocols choice of best paths. The purpose of a routing protocol includes: Discovery of remote networks Maintaining up-to-date routing information 维护必威体育精装版路由信息 Choosing the best path to destination networks Ability to find a new best path if the current path is no longer available当前路径无法使用时找出新的??佳路径 4. What are the components of a routing protocol? Data structures, Algorithm, Routing protocol messages(路由协议消息: 路由协议使用各种消息找出邻近的路由器，交换路由信息，并通过其它一些任务来获取和维护准确的网络信息。). 5. Dynamic Routing Advantages and Disadvantages Dynamic routing advantages: Administrator has less work maintaining the configuration when adding or deleting networks. Protocols automatically react to the topology changes. Configuration is less error-prone. More scalable, growing the network usually does not present a problem. Dynamic routing disadvantages: Router resources are used (CPU cycles, memory and link bandwidth). More administrator knowledge is required for configuration, verification, and troubleshooting. 6. 7. Interior Gateway Protocols (IGP) are used for intra-autonomous system routing - routing inside an autonomous system Exterior Gateway Protocols (EGP) are used for inter-autonomous system routing - routing between autonomous systems 8. The metric used by the routing protocol RIP is hop count, which is the number of routers that a packet must traverse in reaching another network. OSPF uses bandwidth to determine the shortest path. RIP 路由协议使用的度量是跳数，即一个数据包在到达另一个网络过程中必须经过的路由器