What is subinterface VLAN?
VLANs enable a device to carry multiple discrete broadcast domains, allowing a single switch to function as if it were multiple switches.
What is meant by a native VLAN?
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.
What is the native VLAN used for?
Conclusion. Finally, we can conclude that the basic purpose of native VLAN is to serve it as a common identifier on opposing ends of a trunk link. To carry untagged traffic which is generated by a computer device attached to a switch port, which is configured with the native VLAN.
What is default native VLAN?
The default VLAN for Cisco switches is VLAN 1. VLAN 1 has all the features of any VLAN, except that you cannot rename it and you cannot delete it. Layer 2 control traffic, such as CDP and spanning tree protocol traffic, will always be associated with VLAN 1 – this cannot be changed.
What is a subinterface used for?
A subinterface is a virtual interface created by dividing one physical interface into multiple logical interfaces. A sub-interface in a Cisco Router uses the parent physical interface for sending and receiving data.
How do I enable subinterface?
To configure additional IP interfaces over the VLAN major interface:
- Create a new VLAN subinterface by adding a unique subinterface number to the interface identification command. host1(config-if)#interface fastEthernet 4/1.2.
- Assign a VLAN ID for the subinterface.
- Assign an IP address and mask.
Is VLAN 1 Native VLAN?
Default VLAN is VLAN 1 which cannot be shut down in any case and also it carries controlling traffic. In the case of Cisco (and most vendors), the Default Native VLAN is VLAN 1.
Is native VLAN tagged or untagged?
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 the difference between VLAN and native VLAN?
When frames traverse a Trunk port, a VLAN tag is added to distinguish which frames belong to which VLANs. Access ports do not require a VLAN tag, since all incoming and outgoing frames belong to a single VLAN. The Native VLAN is simply the one VLAN which traverses a Trunk port without a VLAN tag.
Which VLAN should be native?
VLAN 1
As VLAN 1 is the default native VLAN, it is used for untagged traffic. If you need to pass frames tagged VLAN 1, you will not be able to, by default. The solution is to change the default VLAN to another value. Once this is done, VLAN 1 can be passed across the trunk just the same as any other VLAN.
What is native VLAN and normal VLAN?
An Access port (or “untagged port” in the non Cisco world) is a switch port which carries traffic for only one VLAN. Access ports do not require a VLAN tag, since all incoming and outgoing frames belong to a single VLAN. The Native VLAN is simply the one VLAN which traverses a Trunk port without a VLAN tag.
How do you assign a VLAN to a subinterface?
To assign a VLAN ID to a subinterface (or to modify the VLAN ID that is currently assigned to a subinterface), use the dot1q vlan command in subinterface configuration mode. To remove the VLAN ID assigned to a subinterface, use the no form of this command.
Can a native VLAN be configured on a subinterface?
” The native Vlan (usually Vlan1) cant be configured on a subinterface for IOS earlier than 12.1 (3)T, so need to be configured on the physical interface…”
Is the L3 interface a switchport or a VLAN?
If the interface is acting as a default gw for a subnet, then it has an IP address and is no longer a “switchport” as such, it is a L3 interface. A L3 interface (which is an Interface with an IP address) has only 1 vlan “attached” to it. This vlan is “untagged”, in Cisco language this means native.
What does the native VLAN on a Cisco switch do?
The Native VLAN essentially carries all traffic that does not have a specific VLAN tag associated with it. For instance, let’s say you are using a cisco switch and only issue the following commands: At that point, this specific interface is not assigned to a specific VLAN (e.g., switchport access vlan 13).
What does a subinterface do on a router?
On a router, sub-interfaces can be defined to allow different VLAN IDs over a trunk from a connected switch to communicate, each VLAN ID will be on different subnet, the sub-interfaces act as default gateways and have nothing to do with trunking.