Which two protocol can detect native vlan mismatch errors? (Choose two.)

IT Questions BankWhich two protocol can detect native vlan mismatch errors? (Choose two.)
Which two protocol can detect native vlan mismatch errors? (Choose two.) 1ITExamAnswers Staff asked 6 months ago
Question:
Which two protocol can detect native vlan mismatch errors? (Choose two.)

  • CDP
  • VTP
  • DTP
  • STP
  • PAGP

Explanation:

A
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)

D
http://blog.ine.com/2008/07/17/pvst-explained/

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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