Lan And Wan Connectivity

ASSIGNMENT NO. 01 LAN AND WAN CONNECTIVITY

Submitted By: SUKANNYA CHETRY (BA/08/EC/002) ANKITA RAJ (BA/08/EC/003) KRITHIKA SUNDARESAN (BA/08/EC/004) SANGEETA BURAGOHAIN (BA/08/EC/005) POWLOMI ROY (BA/08/EC/010) SARBARI CHAKRABORTY (BA/08/EC/012) RIMA KAUSHIK (BA/08/EC/015)

COURSE NAME: FUNDAMENTALS OF TELECOMMUNICATION ENGINEERING COURSE CODE: EC-2101 SUBMISSION DATE: 28-10-2009 SESSION: JULY-DECEMBER, 2009.

NORTH EASTERN REGIONAL INSTITUTE OF SCIENCE AND TECHNOLOGY (DEEMED UNIVERSITY) Under the Ministry of Human Resource Development, Govt. of India Itanagar, Arunachal Pradesh, India, Nirjuli-791109

0

CONTENTS: 1. Computer networking 1.1 Categories

2. LAN-Local Area Network 2.1 Examples 2.2 History 2.3 Features 2.4 Technology 2.5 Networking equipment 2.6 Cabling

3. WAN-Wide Area Network 3.1 Examples of WAN 3.2 Features 3.3 WAN technology 3.4 Components of WAN 3.5 Networking equipment

4. LAN versus WAN

5. Recent trends 5.1 LAN 5.2 WAN

1

1. Computer networking: Computer networking is the engineering discipline concerned with communication between computer systems or devices. Computer networking is sometimes considered a sub-discipline of telecommunications, computer science, information technology and computer engineering. A computer network is any set of computers or devices connected to each other with the ability to exchange data. All devices are interconnected to allow communication with a variety of different kinds of media, including twisted pair copper wire cable, coaxial cable, optical fiber, power lines and various wireless technologies. The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the internet).

1.1 Categories: Networks can be categorized in several different ways viz. by scale, by network design, network protocols, etc. One way to categorize the different types of computer networks is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:        

LAN - Local Area Network WLAN - Wireless Local Area Network WAN - Wide Area Network MAN - Metropolitan Area Network SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network PAN - Personal Area Network DAN - Desk Area Network

LAN and WAN were the original categories of area networks, while the others have gradually emerged over many years of technology evolution.

2. LAN - Local Area Network: A computer network established within a building or a campus or a small geographical area is called local area network or LAN. In other words, “a LAN is a group of

2

computers and associated devices that share a common communication line or a wireless link” (i.e. microwave link or satellite link).

Fig 1: LAN connectivity

2.1 Examples of LAN: 1. A LAN may be established on a University campus or between office blocks in an office park. 2. A big corporate perhaps like Anglo American, could generally have a LAN that might span several buildings.

2.2 History: As larger universities and research labs obtained more computers during the late 1960s, there was increasing pressure to provide high-speed interconnections. A report in 1970 from the Lawrence Radiation Laboratory detailing the growth of their "Octopus" network gives a good indication of the situation. Cambridge Ring was developed at Cambridge University in 1974 but was never developed into a successful commercial product. Ethernet was developed at Xerox PARC in 1973–1975, and filed as U.S. Patent 4,063,220. In 1976, after the system was deployed at PARC, Metcalfe and Boggs 3

published their seminal paper, "Ethernet: D:WAN technology distributed PacketSwitching For Local Computer Networks." ARCNET was developed by Datapoint Corporation in 1976 and announced in 1977. It had the first commercial installation in December 1977 at Chase Manhattan Bank in New York.

2.3 Features: 

LANs operate in a limited space, usually up to 1 km range.



The smallest home LAN can have exactly two computers; a large LAN can accommodate many thousands of computers.



LANs are typically owned, controlled, and managed by a single person or organization.



A LAN is useful for sharing resources other applications. A LAN in turn often connects to other LANs, and to the Internet or other WAN.



Individual users can share data or files on a LAN as if the data or files resided on their respective computers; a central computer used for this purpose is called a server. Laser printers and other peripheral equipment can be connected to a LAN for common use.



Coaxial and fiber-optic cables are popular communication lines for LANs because they provide fast data transmission and are easy to install.



Many LANs are divided into logical groups called subnets. An Internet Protocol (IP) "Class A" LAN can in theory accommodate more than 16 million devices organized into subnets.

2.4 Technology: Main LAN technologies: 

Ethernet: It is the most popular LAN technology today.



Token ring: The data is transmitted in tokens.



FDDI: Fiber Distributed Data Interface is a fiber optic token ring LAN. 4



ARCNET: Attached resources Computer Network was first LAN based networking system.

Switched Ethernet is the most common Data Link Layer implementation on local area networks. At the Network Layer, the Internet Protocol has become the standard. However, many different options have been used in the history of LAN development and some continue to be popular in niche applications. Smaller LANs generally consist of one or more switches linked to each other—often at least one is connected to a router, cable modem, or ADSL modem for Internet access. Larger LANs are characterized by their use of redundant links with switches using the spanning tree protocol to prevent loops, their ability to manage differing traffic types via quality of service (QoS), and to segregate traffic with VLANs. Larger LANS also contain a wide variety of network devices such as switches, firewalls, routers, load balancers, sensors. LANs may have connections with other LANs via leased lines, leased services, or by tunneling across the Internet using virtual private network technologies. ARCNET, Token Ring and many other technologies have been used in the past, and G.hn may be used in the future, but Ethernet over twisted pair cabling, and Wi-Fi are the two most common technologies currently in use.

2.5 Networking equipment: Most local area networks are built with relatively inexpensive hardware such as Ethernet cables, network adapters, and hubs. Wireless LAN and other more advanced LAN hardware options also exist. Specialized operating system software may be used to configure a local area network. For example, most flavors of Microsoft Windows provide a software package called Internet Connection Sharing (ICS) that supports controlled access to LAN resources.

2.6 Cabling: Early LAN cabling 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, and in 1984 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 basis of most LANs today. In addition, fiber-optic cabling is increasingly used. 5

3. WAN - Wide Area Network: A WAN or wide area network is a geographically-dispersed collection of LAN’s. As the term implies, a WAN spans a large physical distance. Thus a WAN may be defined as “a data communication network that spans large geographic area, such as a state, province or country”.

Fig 2: WAN connection over the earth

Fig 3: Interconnectivity of LAN and WAN

6

3.1 Examples of WAN: 

Internet: It is a worldwide public WAN.



ARPANET: It is a WAN network established by Advance Research Project Agency of U.S.A. for its own use, connecting about 40 universities and research institutions throughout U.S.A. and Europe.



INDONET: It is a WAN established by CMC( Computer Maintenance Corporation) India to link 3 IBM/4361 systems each at Mumbai, Kolkata and Chennai and a DPD 11/44 system at New Delhi.

3.2 Features: 

WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs).



The medium used for WANs are telephone lines, microwave links and satellite links.



Transmission rate usually range from 1200 bps to 6 Mbps, although some connections such as ATM and Leased lines can reach speeds greater than 156 Mbps.



The cost to transmit data in WAN may be high because the transmission media are eased or paid lines or links.



A WAN may not be owned by a single organization but it operated under collective ownership and management.



WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

3.3 WAN technology: 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.

7

Network protocols deliver transport and addressing functions. Protocols are “pre-defined rules, procedures and agreements for the exchange of data/information through WAN”. Protocols including Packet over SONET/SDH, MPLS, ATM and Frame relay are often used by service providers to deliver the links that are used in WANs. X.25 was an important early WAN protocol, and is often considered to \ be the "grandfather" of Frame Relay as many of the underlying protocols and functions of X.25 are still in use today (with upgrades) by Frame Relay. The protocol applicable presently is known as TCP/IP (Transmission Control Protocol/ Internet Protocol). The world's most popular WAN is the Internet. Some segments of the Internet, like VPNbased extranets, are also WANs in themselves. Finally, many WANs are corporate or research networks that utilize leased lines.

3.4 Components of WAN: 1. Access routers: These are the gateway devices connected to the local area networks (LAN) . The access router connects to a switch or hub on the local network and serves as a gateway to the WAN. The access routers establish LANto-LAN connections and forward network traffic between users at the remote sites.

2. WAN connections: These are the actual connectivity between sites. Common WAN links are public networks like the Internet, private networks such as lines leased from service providers, and the public phone system. The speed of a WAN connection depends on its capacity and characteristics. Analog and ISDN (Integrated Services Digital Network) links are common and inexpensive, but lack the performance of faster technologies and require a dial-up connection between sites. In other words, the link is temporary and must be reestablished every time information is sent. DSL (digital subscriber line) and cable modem links are much faster and always on; these links are permanent and don’t require one modem to dial into another. 3. Security strategies: These prevent any unauthorized people from accessing communications between sites, particularly when they travel over public networks like the Internet.

8

3.5 Networking equipments: WANs generally utilize different and much more expensive networking equipment than do LANs. Key technologies often found in WANs include SONET, Frame Relay, and ATM.

4. LAN versus WAN: 

Whereas a LAN (local area network) is a network that links computers, printers and other devices located in an office, a building or even a campus , a WAN (wide area network) is a system that extends for greater distances and is used to connect LANs (local area networks) together.



A LAN is generally referred to a network contained within a building or an office or a campus. A WAN is a network that connects campuses.



To set up a LAN -relatively speaking- is cheap. WAN's are expensive.



WAN is generally slower than LAN. The data transmission speed in LAN may be up to 10 Mbps, whereas in WAN it is generally about 1/10th of that in LAN.

5. Recent trends: 5.1 LAN: An Ethernet is the most popular LAN technology in use today, which provides a data transmission speed of up to 10 Mbps. For high transmission speed of data, Fast Ethernet IEEE has been established, which raises the data transfer speed to 100 Mbps with minor changes in cable structure. Gigabit internet connections with a speed of 1000 Mbps are also available. The most common protocols in use today are TCP/IP, IPX, DECnet, Apple Talk etc. 5.2 WAN: WANs are moving towards higher bandwidth which can only be delivered by technology at speeds high enough to satisfy the need for bandwidth. 9

Wi-Fi is the technology for connecting clients remotely and is the fastest growing technology offered by all the major players in this market. Wi-Fi or 802.11g is wireless connectivity offering to connect between 11 and 56Mbps and even higher. The advantage of wireless technology is it’s lack of the need of physical wire/copper or Fiber to connect to the client. Another means of connecting is Asynchronous Transfer Mode (ATM) and this certainly offers the fastest Wide Area Connection available today. Speeds start at 155Mbps and running to approx 622Mbps, although with recent technology, we can expect speeds to be significantly higher.

10