Which two protocols can detect native vlan mismatch errors?

2 thoughts on “Which two protocols can detect native vlan mismatch errors?”

1. Agree, A & B

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2. Should be CDP and STP not VTP.

   Explanation for CDP
   Oct 5 23:29:16: %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on GigabitEthernet11/43 (512),
   with WS-C2950-12 FastEthernet0/6 (1)

   Explanation for STP
   Case 1: Change the native VLAN on SW1 connection to R3:
   SW1:
   interface FastEthernet 1/3
   switchport trunk native vlan 2
   Rack1SW2#
   %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer vlan id 2 on FastEthernet1/3 VLAN1.
   %SPANTREE-2-BLOCK_PVID_PEER: Blocking FastEthernet1/3 on VLAN2. Inconsistent peer vlan.PVST+: restarted the
   forward delay timer for FastEthernet1/3
   %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet1/3 on VLAN1. Inconsistent local vlan.PVST+: restarted the
   forward delay timer for FastEthernet1/3
   Note that SW2 detects untagged packet with VLAN ID 2, which does not correspond to the locally configured default native
   VLAN 1. The corresponding port is put in «inconsistent» state. The reason SW2 detects this condition (and not SW1) is
   because SW1 sending SSTP BPDUs and SW2 is not (it receives superios BPDUs). As soon as native VLAN is converted back
   to «1» on SW1, consistency is restored:

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