Types of VLANs

“Hello, i am getting difficulty in the types of VLAN?? Please explain the following: How many types of VLAN are existing? Explain each type? Types of traffic VLAN can carry?”

There are different types of VLANs. The type of network traffic they carry defines a particular type of VLAN and others derive their names due to the type or a specific function the VLAN performs. The following describes common VLAN:

Default VLAN

All switch ports become a member of the default VLAN after the initial boot up of the switch. Having all the switch ports participate in the default VLAN makes them all part of the same broadcast domain. This allows any device connected to any switch port to communicate with other devices on other switch ports. 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. In the figure, VLAN 1 traffic is forwarded over the VLAN trunks connecting the S1, S2, and S3 switches. It is a security best practice to change the default VLAN to a VLAN other than VLAN 1; this entails configuring all the ports on the switch to be associated with a default VLAN other than VLAN 1. VLAN trunks support the transmission of traffic from more than one VLAN. Although VLAN trunks are mentioned throughout this section, they are explained in the next section on VLAN trunking.

Note: Some network administrators use the term “default VLAN” to mean a VLAN other than VLAN 1 defined by the network administrator as the VLAN that all ports are assigned to when they are not in use. In this case, the only role that VLAN 1 plays is that of handling Layer 2 control traffic for the network.


VLAN Types

A data VLAN is a VLAN that is configured to carry only user-generated traffic. A VLAN could carry voice-based traffic or traffic used to manage the switch, but this traffic would not be part of a data VLAN. It is common practice to separate voice and management traffic from data traffic. The importance of separating user data from switch management control data and voice traffic is highlighted by the use of a special term used to identify VLANs that only carry user data – a “data VLAN”. A data VLAN is sometimes referred to as a user VLAN.

Native VLAN

A native VLAN is assigned to an 802.1Q trunk port. An 802.1Q trunk port supports traffic coming from many VLANs as well as traffic that do not come from a VLAN. The 802.1Q trunk port places untagged traffic (traffic that does not come from a VLAN) on the native VLAN. In summary, the native VLAN observes and identifies traffic coming from each end of a trunk link.

Management VLAN

A management VLAN is any VLAN you configure to access the management capabilities of a switch. Your configured management VLAN is to be assign with an IP address and subnet mask. Any of a switch VLAN could be configured as the management VLAN if you has not configured or define a unique VLAN to serve as the management VLAN. In some cases, a network administrator proactively defines VLAN 1 as the management VLAN; this enables a loophole for an unauthorized connection to a switch.

Voice VLAN

Types of VLANs

Voice VLAN is configured to carry voice traffic. Voice VLANs are mostly given transmission priority over other types of network traffic. Communication over the network is not complete without phone calls. More calls are made over the network than other forms of s message transmission. Sending emails and text messages are also forms of inter-relations but listening to a real voice provides legitimacy and assurance.

It is considered among network administrators to design a network that supports VoIP with an assured bandwidth to ensure voice quality, and capability to be routed around congested areas on the network with minimal delays (150-180 milliseconds).


More Related Networking Tips:

‘What Happens in the VLAN Stays in the VLAN?’

How Private VLANs Work?

How to Configure Private VLANs on Cisco 3560 Switches?

VLAN Trunking Protocol (VTP) & VTP Modes

Types of Networks

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