VLAN Trunking Protocol
VLAN Trunking Protocol is a Cisco proprietary protocol that propagates the definition of Virtual Local Area Networks on the whole local area network. To do this, VTP carries VLAN information to all the switches in a VTP domain. VTP advertisements can be sent over 802.1Q, and ISL trunks. VTP is available on most of the Cisco Catalyst Family products. Using VTP, each Catalyst Family Switch advertises …
What is VLAN pruning in Cisco switch?
VLAN Trunking Protocol (VTP) pruning is a feature in Cisco switches, which stops VLAN update information traffic from being sent down trunk links if the updates are not needed. If the VLAN traffic is needed later, VLAN Trunking Protocol (VTP) will dynamically add the VLAN back to the trunk link.
Which VLANs are eligible for VTP pruning?
VTP pruning should only be enabled on VTP servers, all the clients in the VTP domain will automatically enable VTP pruning. By default, VLANs 2 – 1001 are pruning eligible, but VLAN 1 can’t be pruned because it’s an administrative VLAN. Both VTP versions 1 and 2 support pruning.
What is the use of VLAN Trunking Protocol?
VLAN Trunking Protocol (VTP) is used to communicate VLAN information between switches in the same VTP domain. VLAN Trunking Protocol (VTP) pruning is a feature in Cisco switches, which stops VLAN update information traffic from being sent down trunk links if the updates are not needed.
What is the purpose of VTP pruning?
VTP pruning helps improve proper allocation and use of network bandwidth by reducing unnecessary flooded traffic, such as broadcast, multicast, unknown, and flooded unicast packets. VTP pruning is disabled by default in Cisco switches.
What does VLAN pruning mean?
VLAN Trunking Protocol (VTP) pruning is a feature in Cisco switches, which stops VLAN update information traffic from being sent down trunk links if the updates are not needed. If the VLAN traffic is needed later, VLAN Trunking Protocol (VTP) will dynamically add the VLAN back to the trunk link.
What does pruning mean in networking?
Pruning is the process of deleting irrelevant parts of a belief network before invoking inference. Consider the network in Figure 9(a) for an example, where is an evidence variable and is a query variable. One can prune node from the network, leading to the network in Figure 9(b).
What is the use of VTP pruning?
VTP pruning optimizes the usage of network bandwidth by restricting the flooded traffic to only those trunk ports that can reach all the active network devices.
How do I enable VLAN pruning?
Note: VTP Pruning is disabled by default on all Cisco Catalyst switches and can be enabled by issuing the "set vtp pruning enable" command. If this command is issued on the VTP Server(s) of your network, then pruning is enabled for the entire management domain.
What is the difference between pruning and dropout?
Dropout drops certain activations stochastically (i.e. a new random subset of them for any data passing through the model). Typically this is undone after training (although there is a whole theory about test-time-dropout). Pruning drops certain weights, i.e. permanently drops some parts deemed “uninteresting”.
How do I enable pruning on a Cisco switch?
To enable VTP pruning on a Cisco IOS switch, you use the vtp pruning VLAN configuration command. Once VTP pruning is enabled, you can optionally configure a prune eligible list if you want to limit the VLANs that can be pruned.
How do I know if VTP is pruning?
– Verify that VTP Pruning is functioning properly by viewing the pruning list on SW1. As shown above from the SW3 show interface trunk output you can see that on port Fa1/13 the VLAN's that are forwarding and not pruned on that trunk link are VLAN's 1 and 10.
What is native VLAN?
A native VLAN is a special VLAN whose traffic traverses on the 802.1Q trunk without any VLAN tag. A native VLAN is defined in 802.1Q (it supports untagged traffic while inter-switch link doesn't support untagged traffic.)
How is VLAN configured?
You configure VLANs in vlan global configuration command by entering a VLAN ID. Enter a new VLAN ID to create a VLAN, or enter an existing VLAN ID to modify that VLAN. When you have finished the configuration, you must exit VLAN configuration mode for the configuration to take effect.
What is Switchport trunk pruning?
VTP pruning allows the switch to not forward user traffic for VLANs that are not active on a remote switch. This feature dynamically prunes unneeded traffic across trunk links. If the VLAN traffic is needed at a later date, VTP will dynamically add the VLAN back to the trunk.
How does DTP work?
The Dynamic Trunking Protocol (DTP) is a proprietary networking protocol developed by Cisco Systems for the purpose of negotiating trunking on a link between two VLAN-aware switches, and for negotiating the type of trunking encapsulation to be used. It works on Layer 2 of the OSI model.
How do I know if VTP is pruning?
– Verify that VTP Pruning is functioning properly by viewing the pruning list on SW1. As shown above from the SW3 show interface trunk output you can see that on port Fa1/13 the VLAN's that are forwarding and not pruned on that trunk link are VLAN's 1 and 10.
What are the different types of pruning?
In pruning, there are three primary types of pruning cuts, thinning cuts, reduction cuts, and heading cuts, each giving different results in growth and appearance.
Why can't VLAN 1 be pruned?
VLAN 1 can’t be pruned because it’s an administrative VLAN. All the version of VTP i.e. VTP version 1, VTP version 2 and VTP version 3 support VTP pruning. To enable VTP pruning on a Cisco IOS switch, use the VTP VLAN pruning configuration command.
Does SW3 forward to VLAN 10?
SW3 received the broadcast and forwards to a connected Access port on Vlan 10. SW4 received the broadcast on trunk port but does not forward to access port since no access port with Vlan 10 membership. Now, after enabling VTP pruning on all the switches, let’s see what change happens from the previous scenario.
Is Vlan 10 relayed to SW1?
Once it is enabled, the broadcast on Vlan 10 from SW2 is forwarded to SW1 however, it is not relayed to all trunk ports. Seeing that no Access port membership is there on SW4, the Broadcast of Vlan pruning is only relayed to trunk port of SW3 and not towards SW4.
What is VTP pruning?
VTP pruning helps improve proper allocation and use of network bandwidth by reducing unnecessary flooded traffic, such as broadcast , multicast, unknown, and flooded unicast packets. VTP pruning is disabled by default in Cisco switches. VTP pruning helps to send broadcasts only to those trunk links that actually needs the information.
How to enable VTP pruning on Cisco switch?
To enable VTP pruning on a Cisco IOS switch, you use the vtp pruning VLAN configuration command. Once VTP pruning is enabled, you can optionally configure a prune eligible list if you want to limit the VLANs that can be pruned. The Example below demonstrates how to enable VTP pruning on Switch.
Does VTP pruning work on VLAN 7?
For example, if switch A does not have a port configured for VLAN 7, and broadcast is sent throughout VLAN 7, that broadcast or traffic will not pass through the trunk link to switch A. VTP pruning should only be enabled on VTP servers, all the clients in the VTP domain will automatically enable VT P pruning.