『Troubleshooting的系统方法』 STEP1: Define the PRoblem you are eXPeriencing
STEP2: Gather relevant facts about the situation
STEP3: Consider the possibilities.Use the information you have and your knowledge of Cisco prodUCts to isolate the problem
STEP4: Formulate an action plan to solve this problem
STEP5: Implement your action plan and attempt to fix the problem
STEP6: What were the resuls of your implementation?Did it fix the problem?List your results and observations below
STEP7: If you solution did not fix the problem,repeat the process again.If your solution did fix the problem,ducoment your fix below
请牢记上面的系统排错程序,进行下面的TroubleShooting练习。
CASE Ⅰ: 实验拓扑:
描述: 某公司核心运行的是OSPF路由协议。如上述实验拓扑所示,核心路由CORE的所有端口都属于OSPF Area 0。公司的两个分支机构Branch1、Branch2,由于设备陈旧,只能运行Rip路由协议,并最终接入公司核心网络。(每个分支机构下,还有多个部门,因此有多个网段,在实验中我们使用loopback端口来模拟这些网段。)
下面以CASE Ⅰ为例,用cisco的TroubleingShooting的系统方法进行排错。 步骤一. 经验判定(Define the problem you are experiencing) 公司总部的用户不能连接两个分支机构的任何一台服务器及主机,由此判定这不是工作站出现故障造成的。
步骤二.
收集路由相关信息(Gather relevant facts about the situation.) 登陆CORE路由器,测试基本的连通性。 1.Ping命令检查Branch的WAN、LAN接口: 2.检查CORE的路由表 CORE#show ip route 发现没有任何RIP网段的路由信息。 步骤三. 故障定位(Consider the possibilities.Use the information you haveyou’re your knowledge of Cisco products to isolate the problem.) 故障与routing protocol有关,可能是RIP路由信息没有被重发布到OSPF域中。
步骤四. 提出解决方案(Formulate an action plan to solve this problem) 获得更多其它路由信息,检查重发布是否正确配置
步骤五. 实施方案,记录所有的更改(Implement your action plan and attempt to fix the problem.Log all changes made.remember!) 使用show ip interface brief show ip route show ip protocols show ip ospf database 发现是由于RIP网络的子网信息没有发布到OSPF域中,因为在ospf redistribute命令行中少了subnets的要害字。 修改路由配置: Branch1(config)#router ospf 1 Branch1(config-router)#redistribute rip subnets
步骤六. 检查修改配置后的结果是否解决故障(What were the resuls of your implementation?Did it fix the problem?List your results and observations below) 使用show ip route Ping