A network administrator is diagnosing Layer 2 operational issues across several switch ports in an enterprise campus network. Match each observed switch log message or diagnostic symptom on the left to its correct underlying root cause on the right.
- %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on interface GigabitEthernet0/1 (10), with Switch-B GigabitEthernet0/1 (20).Inconsistent 802.1Q untagged traffic configurations between interconnected switch trunk interfaces.
- %SPANTREE-2-BLOCK_BPDUGUARD: Received BPDU on port FastEthernet0/24 with BPDU Guard enabled. Disabling port.An unauthorized switch or device sending Bridge Protocol Data Units was connected to an edge access port.
- Interface FastEthernet0/5 statistics display an abnormally high count of late collisions, FCS errors, and deferred transmissions under high traffic load.Speed/duplex autonegotiation failure where one side operates in half-duplex mode and the other in full-duplex mode.
- Interface GigabitEthernet0/2 status displays 'down/down (not-connect)' after trunking failed to form, with DTP set to 'desirable' on Switch-A and 'nonegotiate' on Switch-B.Dynamic Trunking Protocol negotiation suppressed on one end while expecting dynamic trunking signals from the peer.
Cevap
1. CDP native VLAN mismatch log pairs with inconsistent 802.1Q untagged traffic configurations.
2. SPANTREE BPDU Guard error log pairs with an unauthorized switch or device sending BPDUs on an edge access port.
3. Late collisions and FCS errors statistics pair with speed/duplex autonegotiation failure (half/full mismatch).
4. DTP desirable vs nonegotiate failure pairs with Dynamic Trunking Protocol negotiation suppressed on one end.
2. SPANTREE BPDU Guard error log pairs with an unauthorized switch or device sending BPDUs on an edge access port.
3. Late collisions and FCS errors statistics pair with speed/duplex autonegotiation failure (half/full mismatch).
4. DTP desirable vs nonegotiate failure pairs with Dynamic Trunking Protocol negotiation suppressed on one end.
Each diagnostic log or symptom matches its precise root cause based on standard Layer 2 operation: CDP mismatch logs match native VLAN discrepancies; BPDU Guard err-disable events match rogue switch detection on edge ports; late collisions match duplex autonegotiation failures; and DTP dynamic trunking failure matches a nonegotiate command suppressing DTP frame generation.
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Anahtar Kavram
Troubleshooting Layer 2 switching, VLAN trunking, STP port security, and physical interface negotiation issues