Which IOS command enables the VTP feature that eliminates unnecessary trunk traffic being flooded to switches that do not have memberships in particular VLANs?
A. vtp mode client
B. no vtp mode
C. vtp v1-mode
D. vtp pruning
Correct Answer: D
Explanation/Reference:
Answer:
To enable pruning on a switch operating in VLAN Trunk Protocol (VTP) server mode, enter the vtp pruning command at the global configuration prompt.
switch(config)# vtp pruning
VTP pruning enhances network bandwidth usage by restricting unnecessary flooded traffic on trunk links. If a trunk link does not have devices in the VLAN attached, flooded traffic on that VLAN is blocked. VTP pruning can reduce broadcasts, multicasts, unknown traffic, and flooded unicast packets.
Enabling VTP pruning on a switch in VTP server mode enables pruning for the entire domain.
Multicast and unicast traffic are not blocked for the VLANs that are not being pruned.
There are three modes in VTP: server, client, and transparent. The main differentiator among the three modes is whether a switch can create, modify, or delete VLANs. A Catalyst switch can create, modify, and delete VLANs in server or transparent mode, but not in client mode. However, VLANs created on a switch in transparent mode apply only to that switch, and information about these VLANs is not propagated throughout the VTP domain.
The VTP server mode sends or forwards VTP advertisements, synchronizes VLAN configuration information with other switches, and saves the VLAN in NVRAM.
The VTP transparent mode forwards VTP advertisements and saves the VLAN configuration in NVRAM. It does not synchronize VLAN configuration information. A switch in transparent mode can create, delete, and modify VLANs, but changes are not transmitted to other switches in the domain. They only affect the local switch.
The VTP client mode sends or forwards VTP advertisements and synchronizes VLAN configuration information with other switches. It does not save VLAN information in NVRAM. In client mode, VTP clients only can receive VLAN information from VTP servers.
The command vtp mode client sets the switch to client mode. It does not eliminate unnecessary trunk traffic.
The no vtp mode command reverts the VTP mode back to its default state, which is server mode. To set the VTP mode of a VTP client back to server mode, you can use either the no vtp mode command or the vtp server command.
The vtp v1-mode command reverts the VTP version to version 1 (the default version). Use the vtp v2-mode command to set the VTP mode to version 2.
Objective:
Layer 2 Technologies Sub-Objective:
Configure and verify trunking
References:
Cisco > Home > Support > Technology Support > LAN Switching > Virtual LANS/VLAN Trunking Protocol (VLANS/VTP) > Design > Design Technotes > Understanding VLAN Trunk Protocol (VTP)
Cisco > Cisco IOS LAN Switching Command Reference > udld through vtp v2-mode > vtp
Explanation/Reference:
Answer:
To enable pruning on a switch operating in VLAN Trunk Protocol (VTP) server mode, enter the vtp pruning command at the global configuration prompt.
switch(config)# vtp pruning
VTP pruning enhances network bandwidth usage by restricting unnecessary flooded traffic on trunk links. If a trunk link does not have devices in the VLAN attached, flooded traffic on that VLAN is blocked. VTP pruning can reduce broadcasts, multicasts, unknown traffic, and flooded unicast packets.
Enabling VTP pruning on a switch in VTP server mode enables pruning for the entire domain.
Multicast and unicast traffic are not blocked for the VLANs that are not being pruned.
There are three modes in VTP: server, client, and transparent. The main differentiator among the three modes is whether a switch can create, modify, or delete VLANs. A Catalyst switch can create, modify, and delete VLANs in server or transparent mode, but not in client mode. However, VLANs created on a switch in transparent mode apply only to that switch, and information about these VLANs is not propagated throughout the VTP domain.
The VTP server mode sends or forwards VTP advertisements, synchronizes VLAN configuration information with other switches, and saves the VLAN in NVRAM.
The VTP transparent mode forwards VTP advertisements and saves the VLAN configuration in NVRAM. It does not synchronize VLAN configuration information. A switch in transparent mode can create, delete, and modify VLANs, but changes are not transmitted to other switches in the domain. They only affect the local switch.
The VTP client mode sends or forwards VTP advertisements and synchronizes VLAN configuration information with other switches. It does not save VLAN information in NVRAM. In client mode, VTP clients only can receive VLAN information from VTP servers.
The command vtp mode client sets the switch to client mode. It does not eliminate unnecessary trunk traffic.
The no vtp mode command reverts the VTP mode back to its default state, which is server mode. To set the VTP mode of a VTP client back to server mode, you can use either the no vtp mode command or the vtp server command.
The vtp v1-mode command reverts the VTP version to version 1 (the default version). Use the vtp v2-mode command to set the VTP mode to version 2.
Objective:
Layer 2 Technologies Sub-Objective:
Configure and verify trunking
References:
Cisco > Home > Support > Technology Support > LAN Switching > Virtual LANS/VLAN Trunking Protocol (VLANS/VTP) > Design > Design Technotes > Understanding VLAN Trunk Protocol (VTP)
Cisco > Cisco IOS LAN Switching Command Reference > udld through vtp v2-mode > vtp
