Cisco CCNA mock exam questions sample test – Question 349

.A new switch is added to the network, and several production VLANs are shut down.
Which of the following is a probable cause for this scenario? (Choose two.)

A. The new switch has a lower configuration revision number than existing switches.
B. The new switch has a higher configuration revision number than existing switches.
C. The new switch is operating in transparent mode.
D. The new switch is operating in server mode.


Correct Answer: BD

Explanation:
The VLAN database of the new switch will overwrite the VLAN databases of the production switches because it is operating in server mode and has a higher VLAN configuration
revision number. The VLAN Trunking Protocol (VTP) is used to synchronize VLANs between different switches. The VTP configuration revision number is used to determine which
VTP switch has the most current version of the VLAN database, and is incremented whenever a VLAN change is made on a VTP server switch. The show vtp status command is
used to view the configuration revision number, as shown in this sample output:
Switch# show vtp status
VTP Version : 2
Configuration Revision : 62
Maximum VLANs supported locally : 1005
Number of existing VLANs : 24
VTP Operating Mode : Server
VTP Domain Name : Corporate
VTP Pruning Mode : Enabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x45 0x52 0xB6 0xFD 0x63 0xC8 0x49 0x80
This switch has a configuration revision number of 62, which will be compared to other switches in the same VTP domain. If the production switches have a lower configuration
revision number than the new switch, their VLAN databases will be replaced with the VLAN database of the new switch. This could mean that VLANs that formerly existed on those
production switches may be deleted. Any switch ports that had been assigned to VLANs that become deleted will be disabled, possibly resulting in catastrophic network failure. All VTP
switches in the same VTP domain should have a domain password defined, which will protect against a rogue switch being added to the network and causing VLAN database
corruption.
The new switch does not have a lower configuration revision number, since this would cause the new switch to have its VLAN database replaced with the existing production VLANs.
This would not cause the problem described in the scenario.
The new switch is not operating in transparent VTP mode because a switch operating in transparent VTP mode will never synchronize its VLAN database with other switches.
Objective:
LAN Switching Fundamentals
Sub-Objective:
Configure, verify, and troubleshoot VLANs (normal/extended range) spanning multiple switches
References:
Cisco > Support > LAN Switching > Virtual LANS / VLAN Trunking Protocol (VLANS/VTP) > Configure > Configuration Examples and Technotes > Configuring VLAN Trunk Protocol
(VTP) > Document ID: 98154
Cisco > Catalyst 4500 Series Switch Cisco IOS Software Configuration Guide, 12.2(25) > Understanding and Configuring VLANs, VTP, and VMPS