Virtual Local Area Network (VLAN)

Published: 01st June 2009
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Virtual Local Area Network (VLAN)

It is important to have a working understanding of VLAN's underlying technology to fully grasp its idea. Essentially, a LAN (Local Area Network) describes a physical interconnection of computer systems and peripherals (switches, hubs, routers, or bridges) lying within the same segment or connection. This network provides a communication framework to allow the exchange of data and sharing of resources among connected machines.

Normally, the network relies on a Server machine that delivers the communication, sharing, and security resources required by the connected computer systems (Clients). The idea behind a VLAN is that it supports a group of systems and devices situated on different physical LAN environments. This technology provides the communication layer for these segmented network facilities to mimic LAN functions as if they were located in a single, interconnected, physical network, hence the term "Virtual".

The origin of this technology or how it evolved is somewhat vague. According to some network specialists, the idea came mostly from network hardware device manufacturers. Supposedly, it was inspired by the growing implementation of LAN technology in computing environments and was seen as a way to extend the influence their devices had on these networks.

Presumably, the Virtual Local Area Network (VLAN) technology was adopted sometime in 1985 based on the multi-tree Bridge concept. It provided networks with expanded capabilities by removing the limitations set forth by the single spanning tree function. It also enabled the arbitrary implementation of LAN environments.

The emergence of this technology provided network managers with the ability to logically segment networks into varying broadcast domains. These domains may be defined simply with the implementation of bridging programs rather than deploying router devices. The role of the router in this scheme is relegated to providing the communication link among interconnecting VLAN environments.

The vast benefits derived from the implementation of this technology have brought about a drastic increase in the number of possible usage of networking environments. By late November, 2008, a proposal to adopt an Ethernet standard called the HVLAN (Hierarchical VLAN) was being pushed. This evolution in VLAN technology supposedly will extend the use of enterprise-based Ethernet VLAN to various carrier networks.

According to industry experts, this is part of a continuing trend to merge the cost-efficient packet transport mechanism with the VLAN technology. This proposal presumably builds on previous developments like the 802.1ad (Q-in-Q), PBB-TE, 802.1ah (PBB), and Provider Backbone Transport (PBT) among others. These presumably were intended to upgrade the feature sets of traditional Ethernet-based networks.

The adoption of the new VLAN-based technology allegedly attempts to retain core Ethernet features while attempting to anticipate future growths in multipoint network applications like gaming, IPTV, Private LANs, and others.

HVLAN incorporates the hierarchical addressing scheme concept into VLAN tags, similar to the service provided by classless subnets to the IP (Internet Protocol) addressing. It will allow the use of the best match approach when forwarding to nodes, which will considerably reduce the required forwarding entries in core switches.

From an end user point of view, the introduction and implementation of VLAN technology in general is a welcome improvement to legacy network protocols. Considering that in older network environments, the use of geographical locations substantially limited the distance and type of topologies that can be implemented.

With the use of VLAN, physical locations become almost a non-issue and support what may be truly called as a global computing community. The developments in this field of technology have also brought about drastic improvements in the way the Internet has evolved and how communication layers and protocols are adopted.

VLAN has made computing resources available to the user from almost any location reached by the network broadcast. Some of the notable technologies, which directly benefit users from the emergence of this concept, include:

• 10 Gigabit Ethernet;

• ATM (Asynchronous Transfer Mode);

• Ethernet;

• Fast Ethernet;

• FDDI (Fiber Distributed Data Interface);

• Gigabit Ethernet;

• and HiperSockets.

In addition, some of the features introduced into the computer industry by the adoption of VLAN technology are:

• increased network flexibility;

• better security protocol implementations;

• virtual elimination of the impact of physical locations;

• and increase in the number of supported broadcast domains while reducing its size.Angela Catina is a freelance writer who the author of articles such as vLAN, What is VLAN, and How to Buy VLAN Visit Virtual Local Area Network (VLAN).

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