What is Switchport trunk native VLAN?
The switchport trunk native vlan command specifies the native (untagged) VLAN for a Layer 2 interface operating in trunk mode on a Cisco IOS device. This command only takes effect for interfaces that are operating in trunk mode.
Which VLAN are by default enabled on a trunk port?
VLAN 1
A trunk port configured with IEEE 802.1Q tagging can receive both tagged and untagged traffic. By default, the switch forwards untagged traffic in the native VLAN configured for the port. The native VLAN is VLAN 1 by default. The native VLAN can be assigned any VLAN ID.
Is native VLAN needed?
Native VLAN does not carry a tag in the network so older devices easily understand when trunk links are sent. The switches can be configured using dot IQ concept that is 802.1Q tunneling frame. Native VLANs are recognized if they are not tagged to any trunks. It is not necessary to have native VLAN on the trunk.
Does native VLAN need to be tagged?
In Cisco LAN switch environments the native VLAN is typically untagged on 802.1Q trunk ports. This can lead to a security vulnerability in your network environment. It is a best practice to explicitly tag the native VLAN in order to prevent against crafted 802.1Q double-tagged packets from traversing VLANs.
What is native VLAN in Cisco?
Native VLAN: The native VLAN is the one into which untagged traffic will be put when it’s received on a trunk port. This makes it possible for your VLAN to support legacy devices or devices that don’t tag their traffic like some wireless access points and simply network attached devices.
How many trunk VLANs can trunk link carry?
All VLAN IDs, 1 to 4094, are allowed on each trunk. However, you can remove VLANs from the allowed list, preventing traffic from those VLANs from passing over the trunk.
What is a native VLAN?
What is the native VLAN on a Cisco switch?
Summary. An Access port (or “untagged port” in the non Cisco world) is a switch port which carries traffic for only one VLAN. The Native VLAN is simply the one VLAN which traverses a Trunk port without a VLAN tag.