CCNA新版全套PPT（xixismile）13_21-EIGRP理论.ppt

1、-EIGRP路由协议,CCNA (640-802),讲解 By xixismile,作者BLOG：,灵活的网络设计 组播和单播代替广播更新 在网络中任何地方实现手动汇总 100% 无环路的无类路由 支持 WANs and LANs 等价和非等价负载均衡,高级距离矢量协议 快速收敛 支持 VLSM 和不连续的子网 局部更新 支持多种网络层协议,EIGRP 特征,EIGRP 关键技术,邻居发现 使用hello包发现邻居 可靠传输协议 (RTP) 保证EIGRP的包到达所有的邻居 DUAL 弥散更新算法 Selects lowest-cost, loop free, paths to each de

2、stination 协议独立模块 (PDMs) EIGRP 支持 IP, AppleTalk和 Novell NetWare. 每一种网络协议支持EIGRP都有自己独立的模块,EIGRP Neighbor Table,EIGRP Topology Table,EIGRP IP Routing Table,Example: EIGRP Tables,Router C Tables:,DUAL Terminology,对于每个目标网段选择一条最低开销并且无环路的路径 AD =下一条路由器到目标网段的COST FD = 本地路由器的开销 = 下一跳路由器的AD + 本地路由器到下一跳路由器的COST

3、 Lowest-cost = 最低的 FD (Current) successor = COST值最低并且五环路的下一跳路由器 Feasible successor = 无环路的备用路由器 (feasible successor 的AD必须小于当前的successor的FD),Example: DUAL of EIGRP,100,10,20,10,100,100,100,20,10,10,20,A,B,E,J,C,F,G,D,H,I,EIGRP Packets,Hello: 建立邻居关系. Update: 发送路由更新信息. Query: 向邻居发送的请求查询信息. Reply: 用来响应Qu

4、ery信息. ACK: 确认一个可靠的报文.,Initial Route Discovery,EIGRP Metric,Same metric components as IGRP: Bandwidth（带宽） Delay（延迟） Reliability（可靠性） Loading（负载） MTU（最大传输单元） EIGRP metric is IGRP metric multiplied by 256.,EIGRP Metric Calculation,By default, EIGRP metric: Metric = bandwidth (slowest link) + delay (su

5、m of delays) Delay = sum of the delays in the path, in tens of microseconds, multiplied by 256 Bandwidth = 107 / (minimum bandwidth link along the path, in kilobits per second) * 256 Formula with default K values (K1 = 1, K2 = 0, K3 = 1, K4 = 0, K5 = 0): Metric = K1 * BW + (K2 * BW) / (256 load) + K

6、3 * delay If K5 not equal to 0: Metric = metric * K5 / (reliability + K4):,A B C D Least bandwidth 64 kbps Total delay 6,000 A X Y Z D Least bandwidth 256 kbps Total delay 8,000,Delay is the sum of all the delays of the links along the paths:Delay = delay in tens of microseconds x 256 Bandwidth is the lowest bandwidth of the links along the paths:Bandwidth = 10,000,000 / (bandwidt