LAN,+WAN,+virtual+LAN,+wireless+WLAN,+home+network

= 3.3 NETWORKS Local Area Network = § A local area network (LAN) is a computer network covering a small physical area like a home, office, a small group of buildings, like a school or an airport. § As larger universities and research labs obtained more computers during the late 1960s, there was an increasing pressure to provide quick and fast interconnections meaning a connection between the internet. An example, the Cambridge Ring was developed at Cambridge University in 1974 but failed and was never developed into a successful commercial product. § Many companies around the 1980s used cabling which had always been based on various grades of co-axial cable, but IBM's Token Ring used shielded twisted pair cabling of their own design. § 1984 the company StarLAN showed the potential of simple Cat3 //unshielded// twisted pair—the same simple cable used for telephone systems. This led to the development of 10Base-T (and its successors) and structured cabling which is still the backbone of most LANs today. Now increasingly, fiber-optic cabling is being used more often.

§ A wide area network (WAN) is a computer network that covers a broad/large area, any network whose communications links cross metropolitan, regional, or national boundaries. § WANs are used to connect LANs and other types of networks together, so that users and computers in one location can communicate with users and computers in other areas. § Many WANs are built for one particular organization/company and are private. Others, built by Internet service providers, provide connections from an organization's LAN to the Internet. § WANs are often built using leased lines. At each end of the leased line, a router connects to the LAN on one side and a hub within the WAN on the other. Leased lines can be very expensive. Instead of using leased lines, WANs can also be built using less costly circuit switching or packet switching methods. § Academic research into wide area networks can be broken down into three areas: Mathematical models, network emulation and network simulation.
 * Wide Area Network **

§ A virtual LAN, commonly known as a VLAN, is a group of hosts with a common set of requirements that communicate as if they were attached to the same broadcast system, regardless of their physical location. § A VLAN has the same attributes as a physical LAN, but it allows for end stations to be grouped together even if they are not located on the same network. Network repairing can be done through software instead of physically devices. § VLAN’s are to provide the segmentation services traditionally provided by routers in LAN systems § The issues VLAN’s face are its, scalability, scarce, security and network management. § Routers in VLAN provide broadcast filtering, security, address summarization, and traffic flow management. By definition, switches may not bridge Internet Protocol traffic between VLANs as it would violate the integrity of the VLAN broadcast domain/system. § By using VLAN’s, one can control traffic patterns and react quickly to relocate cars. VLAN’s provide the flexibility to adapt to changes in network requirements and allow for simplified administration.
 * Virtual Local Area Network **

** Wireless local area network ** § A wireless local area network (WLAN) links devices to a wireless method (typically spread-spectrum or OFDM radio), and usually provides a connection through an access point to the wider internet. This gives users the mobility to move around within a local coverage area and still be connected to the network. § Wireless Networks have become popular in homes due to its easy setup and an increasingly interest in popularity in Laptop computers. § Some local businesses like coffee shops provide wireless networks sometimes for free so that it brings more people in so they can buy more coffee so the business can make a profit. § Large wireless network projects are being put up in many major cities: New York City, for instance, has begun a pilot program to cover all five boroughs of the city with wireless Internet access which is a major profit gain for that company.

§ A home network or home area network (HAN) is a residential local area network (RLAN) § It is used for communication between digital devices typically setup in the home, usually a small number of personal computers (PC) and accessories, such as printers and mobile computing devices like blackberries. § An important function is the sharing of Internet access, often a broadband service through a cable TV or Digital Subscriber Line (DSL) provider like skyband and to add this, a home server may be added for increased functionality and internet speed. § More recently telephone companies have been using home networking to provide triple play services (voice, video and data) to customers. A home network may consist of the following components: § A broadband modem for connection to the internet (either a DSL modem using the phone line, or cable modem using the cable internet connection). § A residential gateway (sometimes called a router) connected between the broadband modem and the rest of the network. This allows multiple devices to connect to the internet at the same time. Residential gateways, hubs/switches, DSL modems, and wireless access points are often combined. § A PC or multiple PCs including desktops and laptops.
 * Home Network **

= =