路由自环-CCNA中文版PPT下载

路由自环 到达10.4.0.0的包在B和C之间来回传输. 10.4.0.0Down,C在下一个更新周期告诉B,但B可能在C通知他之前将10.4.0.0告诉C,C就认为通过B可到10.4.0.0,B又认为通过C可到10.4.0.0,因此包在B和C之间来回传输 * Slide 4 of 4 Emphasize: In Layer 4, router A receives the new routing table from router B, detects the modified distance vector to network 10.4.0.0, and recalculates its own distance vector to network 10.4.0.0 as 3. If all routers in an internetwork do not have up-to-date, accurate information about the state of the internetwork, they might use incorrect routing information to make a routing decision. The use of incorrect information might cause packets to take less-than-optimum paths or paths that return packets to routers that they have already visited.