Match each switch log message or port status indicator on the left with its corresponding root cause on the right.
- %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet0/1 (10), with Switch-B GigabitEthernet0/1 (20).Mismatched untagged VLAN IDs configured on opposing trunk interface endpoints
- Interface GigabitEthernet0/2 status shows increasing late collisions and FCS frame check sequence errors under high load.Duplex mismatch caused by hardcoding one end to full-duplex while auto-negotiation fails on the other
- %SPAN-4-PORT_BLOCKING: Port GigabitEthernet0/24 blocked by Spanning Tree Protocol due to receiving a superior BPDU.STP root bridge priority misconfiguration or introduction of a rogue switch with a lower priority value
- Access port FastEthernet0/5 is assigned to VLAN 40, but connected hosts cannot communicate and show interface down/line protocol down (inactive VLAN).Missing VLAN entry in the switch local VLAN database (vlan.dat)
Cevap
The CDP native VLAN mismatch log corresponds to mismatched untagged VLAN IDs across a trunk link. Increasing late collisions and FCS errors correspond to a duplex mismatch between connected interfaces. The STP superior BPDU blocked port log corresponds to an unexpected switch advertising a lower STP priority. The inactive access port condition corresponds to a missing VLAN definition in the local switch VLAN database.
Each switch log or status symptom maps directly to a distinct Layer 2 misconfiguration: CDP warning logs pinpoint native VLAN mismatches, late collisions indicate duplex mismatches, superior BPDU logs indicate STP priority conflicts, and inactive port assignments indicate uncreated local VLANs.
Adım Adım Çözüm
Anahtar Kavram
Troubleshooting Layer 2 switching issues including native VLAN mismatches, duplex misconfigurations, STP topology dynamics, and missing VLAN database entries.