CCNA LAB 81: Debugging OSPF Adjacencies
本帖最后由 小乔 于 2022-12-29 11:34 编辑Lab Objective:
The objective of this lab exercise is for you to learn and understand how to debug OSPF adjacencies.
Lab Purpose:
Debugging OSPF adjacencies is a fundamental troubleshooting skill. Using debugging, you can identify issues that may be causing OSPF to stop operating. As a Cisco engineer, as well as in the Cisco CCNA exam, you will be expected to know how to decipher OSPF adjacency debugging messages.
Certification Level:
This lab is suitable for ICND2 and CCNA certification exam preparation.
Lab Difficulty:
This lab has a difficulty rating of 7/10.
Readiness Assessment:
When you are ready for your certification exam, you should complete this lab in no more than 10 minutes.
Lab Topology:
Please use the following topology to complete this lab exercise:
Task 1:
Configure hostnames on R1, R2, and Sw1 as illustrated in the topology.
Task 2:
Configure VLAN4010 on Sw1 and name it OSPF_VLAN. Assign ports FastEthernet0/2 and FastEthernet0/3 to this VLAN as access ports. Configure IP addressing on R1 and R2 FastEthernet0/0 interfaces.
Task 3:
Enable OSPF in area 0 between R1 and R2. For R1, use OSPF process ID 1, and for R2, use OSPF process ID 2. Verify that your OSPF adjacency has formed between R1 and R2. Also verify that the default network type for the Ethernet link between R1 and R2 is broadcast.
Task 4:
Enable OSPF adjacency debugging on R1 using the debug ip ospf adj command. Reset the OSPF process on R2. As the OSPF adjacency re-establishes, verify that you can see the different states that OSPF transitions through as it moves to the FULL state.
Configuration and Verification
Task 1:
For reference information on configuring hostnames, please refer to earlier labs.
Task 2:
For reference information on configuring VLANs and IP addressing, please refer to earlier labs.
Task 3:
For reference information on configuring OSPF, please refer to earlier labs.
Task 4:
R2#debug ip ospf adj
OSPF adjacency events debugging is on
R2#clear ip ospf process
Reset ALL OSPF processes? : yes
*Mar1 02:13:21.660: OSPF: Elect BDR 0.0.0.0
*Mar1 02:13:21.660: OSPF: Elect DR 0.0.0.0
*Mar1 02:13:21.660: DR: none BDR: none
*Mar1 02:13:21.660: OSPF: Remember old DR 192.168.20.1 (id)
*Mar1 02:13:21.721: OSPF: Interface FastEthernet0/0 going Up
*Mar1 02:13:21.721: OSPF: i_up : interface is down
*Mar1 02:13:21.725: OSPF: 2 Way Communication to 192.168.20.1 on FastEthernet0/0, state 2WAY
*Mar1 02:13:21.725: OSPF: Backup seen Event before WAIT timer on FastEthernet0/0
*Mar1 02:13:21.725: OSPF: DR/BDR election on FastEthernet0/0
*Mar1 02:13:21.725: OSPF: Elect BDR 10.1.1.2
*Mar1 02:13:21.729: OSPF: Elect DR 192.168.20.1
*Mar1 02:13:21.729: OSPF: Elect BDR 10.1.1.2
*Mar1 02:13:21.729: OSPF: Elect DR 192.168.20.1
*Mar1 02:13:21.729: DR: 192.168.20.1 (Id) BDR: 10.1.1.2 (Id)
*Mar1 02:13:21.729: OSPF: Send DBD to 192.168.20.1 on FastEthernet0/0 seq 0x1614 opt 0x52 flag 0x7 len 32
*Mar1 02:13:21.733: OSPF: Rcv DBD from 192.168.20.1 on Ethernet0/0 seq 0xEB3 opt 0x52 flag 0x7 len 32mtu 1500 state EXSTART
*Mar1 02:13:21.737: OSPF: NBR Negotiation Done. We are the SLAVE
*Mar1 02:13:21.737: OSPF: Send DBD to 192.168.20.1 on FastEthernet0/0 seq 0xEB3 opt 0x52 flag 0x0 len 32
*Mar1 02:13:21.741: OSPF: Rcv DBD from 192.168.20.1 on FastEthernet0/0 seq 0xEB4 opt 0x52 flag 0x3 len 172mtu 1500 state EXCHANGE
*Mar1 02:13:21.741: OSPF: Send DBD to 192.168.20.1 on FastEthernet0/0 seq 0xEB4 opt 0x52 flag 0x0 len 32
*Mar1 02:13:21.749: OSPF: Rcv DBD from 192.168.20.1 on FastEthernet0/0 seq 0xEB5 opt 0x52 flag 0x1 len 32mtu 1500 state EXCHANGE
*Mar1 02:13:21.749: OSPF: Exchange Done with 192.168.20.1 on FastEthernet0/0
*Mar1 02:13:21.749: OSPF: Send LS REQ to 192.168.20.1 length 84 LSA count 7
*Mar1 02:13:21.749: OSPF: Send DBD to 192.168.20.1 on FastEthernet0/0 seq 0xEB5 opt 0x52 flag 0x0 len 32
*Mar1 02:13:21.753: OSPF: Rcv LS UPD from 192.168.20.1 on FastEthernet0/0 length 332 LSA count 7
*Mar1 02:13:21.757: OSPF: Synchronized with 192.168.20.1 on FastEthernet0/0, state FULL
*Mar1 02:13:21.757: %OSPF-5-ADJCHG: Process 2, Nbr 192.168.20.1 on FastEthernet0/0 from LOADING to FULL, Loading Done
*Mar1 02:13:26.544: OSPF: Rcv LS UPD from 192.168.20.1 on FastEthernet0/0 length 64 LSA count 1
*Mar1 02:13:27.001: OSPF: Rcv LS UPD from 192.168.20.1 on FastEthernet0/0 length 64 LSA count 1R2#undebug all
All possible debugging has been turned off
R2#
NOTE: From the output above, you can clearly see OSPF transition from the 2WAY state to the EXSTART state to the EXCHANGE state and, finally, to the FULL state. Because this is a broadcast network type, a DR and BDR router are also elected. If this were a point-to-point or point-to-multipoint network type, you would not see the DR and BDR election taking place.
来源: CCNA LAB 69: Assigning Multiple Instances to a VLAN Simultaneously
来源: CCNA LAB 70: Configuring Spanning Tree Protocol for Access Ports (PortFast)
来源: CCNA LAB 71: Enabling Rapid Per-VLAN Spanning Tree
来源: CCNA LAB 72: Configure, Verify, and Troubleshoot EtherChannels (Static/PAgP/L...
来源: CCNA LAB 73: Configuring 802.1X Security
来源: CCNA LAB 74: Configuring DHCP Snooping
来源: CCNA LAB75: Configuring OSPF on Point-to-Point Networks
来源: CCNA LAB76: Configuring OSPF on Broadcast Networks
来源: CCNA LAB 77: Configuring the OSPF Router ID Manually
来源: CCNA LAB 78: Configuring the OSPF Passive Interface Manually
来源: CCNA LAB79: Configuring Single-Area OSPFv3
来源: CCNA LAB80: Configuring Multi-Area OSPF {:6_267:}{:6_267:}{:6_267:}{:6_267:}
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