2022年 华为 lab 3.0

题目： AR27,AR28,AR32和AR33运行OSPF，AR28,AR30,AR31和AR34运行ISIS 在AR28上做了双向路由引入，全SITE路由可达。 诊断5：AR34没有学习到两条等价默认路由，只从AR30学习到一条。 一、故障根因判断 1、AR31配置了错误的区域ID，导致AR31与AR34无法建立ISIS 邻居关系 二、故障分析 2.1 在AR34上查看路由表，是否存在两条缺省路由，测试及结果如下所示： <AR34>dis ip routing-table protocol isis Route Flags: R - relay, D - download to fib ------------------------------------------------------------------------------ Public routing table : ISIS Destinations : 3 Routes : 3 ISIS routing table status : <Active> Destinations : 3 Routes : 3 Destination/Mask Proto Pre Cost Flags NextHop Interface 0.0.0.0/0 ISIS-L1 15 10 D 10.5.34.30 GigabitEthernet0 /0/0 10.5.1.30/32 ISIS-L1 15 10 D 10.5.34.30 GigabitEthernet0 /0/0 10.5.129.0/24 ISIS-L1 15 20 D 10.5.34.30 GigabitEthernet0 /0/0 ISIS routing table status : <Inactive> Destinations : 0 Routes : 0 如上测试结果所示，AR34确实只存在一条缺省路由，下一跳指向AR30，缺少一条指向AR31的默认路由， 由拓扑可知AR34需要与AR30和AR31建立了ISIS邻居关系，所以需要进一步检查ISIS邻居关系是否正常。 2.2 在AR34上采用display isis peer命令检查ISIS邻居关系是否正常，测试及结果如下所示： <AR34>display isis peer Peer information for ISIS(1) System Id Interface Circuit Id State HoldTime Type PRI ------------------------------------------------------------------------------- 0000.0000.0030 GE0/0/1 0000.0000.0031.01 Up 8s L1 64 Total Peer(s): 1 如上测试及输出结果所示，AR34只与AR30建立了ISIS邻居关系，与AR31没有建立ISIS邻居关系，需要进一步排查邻居无法建立的原因。 2.3 在AR34上查看ISIS相关参数 <AR34>display isis brief ISIS Protocol Information for ISIS(1) ------------------------------------- SystemId: 0000.0000.0034 System Level: L1 Area-Authentication-mode: NULL Domain-Authentication-mode: NULL Ipv6 is not enabled ISIS is in invalid restart status ISIS is in protocol hot standby state: Real-Time Backup Interface: 10.5.34.34(GE0/0/0) Cost: L1 10 L2 10 Ipv6 Cost: L1 10 L2 10 State: IPV4 Up IPV6 Down Type: BROADCAST MTU: 1497 Priority: L1 64 L2 64 Timers: Csnp: L1 10 L2 10 ,Retransmit: L12 5 , Hello: L1 10 L2 10 , Hello Multiplier: L1 3 L2 3 , LSP-Throttle Timer: L12 50 Interface: 10.5.14.34(GE0/0/1) Cost: L1 10 L2 10 Ipv6 Cost: L1 10 L2 10 State: IPV4 Up IPV6 Down Type: BROADCAST MTU: 1497 Priority: L1 64 L2 64 Timers: Csnp: L1 10 L2 10 ,Retransmit: L12 5 , Hello: L1 10 L2 10 , Hello Multiplier: L1 3 L2 3 , LSP-Throttle Timer: L12 50 ......... -------------------------------------------------------------------------------------------- 通过命令输出所示，AR34是level-1类型的ISIS路由器，并且接口G0/0/0和G0/0/1发布在ISIS中，链路cost相同为10，接口类型为Broadcast. 进一步检测AR34和AR31直连的联通性。 2.4 在AR34上Ping AR31的G0/0/1接口IP。 <AR34>ping 10.5.14.31 PING 10.5.14.31: 56 data bytes, press CTRL_C to break Reply from 10.5.14.31: bytes=56 Sequence=1 ttl=255 time=40 ms Reply from 10.5.14.31: bytes=56 Sequence=2 ttl=255 time=20 ms Reply from 10.5.14.31: bytes=56 Sequence=3 ttl=255 time=10 ms Reply from 10.5.14.31: bytes=56 Sequence=4 ttl=255 time=20 ms Reply from 10.5.14.31: bytes=56 Sequence=5 ttl=255 time=20 ms --- 10.5.14.31 ping statistics --- 5 packet(s) transmitted 5 packet(s) received 0.00% packet loss round-trip min/avg/max = 10/22/40 ms ---------------------------------------------------------------------------------------- 通过命令输出所示，直连链路连通性正常。 2.5 在AR31上查看ISIS邻居状态。 [AR31]dis isis peer Peer information for ISIS(1) System Id Interface Circuit Id State HoldTime Type PRI ------------------------------------------------------------------------------- 0000.0000.0028 GE0/0/2 0000.0000.0031.02 Up 25s L2 64 Total Peer(s): 1 -------------------------------------------------------------------------------------- 通过命令输出所示，AR31只与AR28形成level2的邻居关系，没有和AR34形成邻居关系。 2.6 查看AR31的ISIS相关参数。 <AR31>dis isis brief ISIS Protocol Information for ISIS(1) ------------------------------------- SystemId: 0000.0000.0031 System Level: L12 Area-Authentication-mode: NULL Domain-Authentication-mode: NULL Ipv6 is not enabled ISIS is in invalid restart status ISIS is in protocol hot standby state: Real-Time Backup Interface: 10.5.14.31(GE0/0/1) Cost: L1 10 L2 10 Ipv6 Cost: L1 10 L2 10 State: IPV4 Up IPV6 Down Type: BROADCAST MTU: 1497 Priority: L1 64 L2 64 Timers: Csnp: L1 10 L2 10 ,Retransmit: L12 5 , Hello: L1 10 L2 10 , Hello Multiplier: L1 3 L2 3 , LSP-Throttle Timer: L12 50 Interface: 10.5.130.31(GE0/0/2) Cost: L1 10 L2 10 Ipv6 Cost: L1 10 L2 10 State: IPV4 Up IPV6 Down Type: BROADCAST MTU: 1497 Priority: L1 64 L2 64 Timers: Csnp: L1 10 L2 10 ,Retransmit: L12 5 , Hello: L1 10 L2 10 , Hello Multiplier: L1 3 L2 3 , LSP-Throttle Timer: L12 50 ....... ----------------------- 通过命令输出所示，AR31各相关接口都以加入到ISIS进程中，并且为level1-2路由器。 2.7 查看AR31上ISIS 接口的相关信息。 <AR31>dis isis interface Interface information for ISIS(1) --------------------------------- Interface Id IPV4.State IPV6.State MTU Type DIS GE0/0/1 001 Up Down 1497 L1/L2 No/No GE0/0/2 002 Up Down 1497 L1/L2 No/Yes Loop0 001 Up Down 1500 L1/L2 -- ------------------------------------------------------------------------------------ 通过命令输出所示,AR31的G0/0/1接口为level1-2,接口类型为Broadcast,并发布在ISIS中。AR31和AR34无ISIS邻居关系怀疑是协议配置问题。 2.8 在AR34使用dispaly isis error interface g0/0/1查看是否存在错误计数。 <AR34>dis isis error interface g0/0/1 Statistics of errored packets for GE0/0/1: -------------------------------------------------------------------- LSP packet errors: Longer LSP : 0 Smaller LSP : 0 Mismatched Level : 0 Invalid Sysid : 0 Zero Sequence Number : 0 Illegal IS Type : 0 Zero Checksum : 0 Incorrect Checksum : 0 Bad Authentication : 0 Bad Auth Count : 0 More Protocol TLV : 0 Bad Nbr TLV : 0 Bad Extended IS TLV : 0 Bad IF Addr TLV : 0 Bad Reach TLV : 0 Bad Inter Domain TLV : 0 Mismatched Area Id(L1) : 0 Bad TLV Length : 0 Bad Alias TLV : 0 Bad Area TLV : 0 Bad SRLG TLV : 0 Unknown Adjacency : 0 Bad Protocol ID : 0 Bad Version : 0 Zero Lifetime : 0 Bad Ext Reach TLV : 0 Bad TE Router ID TLV : 0 Bad TE Sub TLV : 0 Hello packet errors: