WIDE AREA NETWORKS AND VIRTUAL PRIVATE NETWORKS
In today's world, business is becoming more scattered across the globe. Yet it is more imperative than ever that business can communicate efficiently, regardless of physical location. To communicate securely and effectively, companies are increasingly employing a WAN (wide area network), or a VPN (virtual private network).
 
Why Wide Area Networks?

A WAN provides reliable, fast and secure communications between two or more points (nodes). Primary applications of a WAN are:

Internet Applications - for Internet access and e-mail
Traditional WAN - LAN-to-LAN connections for e-mail, data transfer and network applications between business sites
Remote LAN Access - for home and mobile users
Extranet - limited access to an intranet for customers and suppliers

Implementing a WAN provides authorised users with seamless access to network resources. This offers excellent efficiencies. Hotels planning onward accommodation for departing guests can access reservation data from their sister hotel's server. Car dealerships can check vehicle availability at their associated dealership. During a company emergency, a Managing Director on holiday in Fiji can access important information from the network securely and efficiently.

A WAN removes the restrictions associated with being absent from the office. Users view and use resources as though they were physically in the office. This capability brings companies excellent efficiencies and conveniences, and opportunities to offer better customer service.
 

What is a Wide Area Network?

A WAN is a network that spans a large geographical area, from across a suburb to worldwide. The link between the sites is provided by a communications carrier, in contrast to the coax, fibre optic or twisted pair cable used in a LAN. Diagrams of WANs typically include a grey cloud, representing the telcommunications provider's responsibility. Beyond nominating the service your organisation requires, your involvement in the processes in this cloud will be minimal, unlike the complete control and ownership you have over your LAN.

Dial-up WAN

As the name suggests, the WAN connection is dialed up each time it is required. Dial-up WANS are appropriate only for organisations where traffic is infrequent and/or minimal, as continual reconnections can prove to be expensive.

In the illustration scenario:

  • office B wants to send data to office D
  • office B dials up to office D
  • data is sent directly to office D

Dial-up WANs are quite flexible, allowing new sites to be added, and an additional destination option offered to existing sites.

Dial-up WANs will typically be connected by ISDN or ADSL. These technologies offer transmissions at speeds far beyond the standard 56Kbps utilised by many organisations.

Permanent WAN

A permanent WAN involves permanent links, leased from a communications carrier, connecting offices. The lines are reserved for use by the company, guaranteeing high performance and optimum speeds.

In the illustration scenario:

  • office A is the main office
  • all permanent links are connected to office A
  • office C wants to send data to office D
  • data is sent to office D via office A

The illustration highlights the most common scenario, where all sites are linked to a common site, and data passes through that site. Alternatively, it is possible to have permanent links from site to site (Office C would have a direct connection to offices A, B, D, E and F), where the data is transferred directly. However, this scenario can be extremely expensive, and escalate the costs of connecting a new site. For example, in the above diagram, if an additional site was added, only one new connection would be required. If each site was directly connected to all sites, an additional 6 connections would be required. The cost and complexity of the latter scenario limits its implementation.

Permanent WANs are ideal for organisations transferring significant amounts of data. With today's ISDN, ADSL, frame relay and ATM technologies, your business data will transfer and the most efficient speeds possible. It will ehance your employee productivity and business performance.
 
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