Stephen Nowell
L01: Prof. Whit Smith
Women’s Shelter Group
Technical Review
Components of Computer Networking (LAN)
Introduction
Computer networks are classified by scale, components, and connection method.
LANs (Local Area Network) are a relatively small network that connects computers in
the same physical location, usually within a building or a campus. As oppose to WAN
(Wide Area Networks) that consist of multiple LANs and can connect different countries
together. How a LAN is connected and what components it uses will determine how fast,
reliable, and accessible the network is.
Commercial Applications of LANs
LANs make up the larger Network configurations that are used today. These
networks are focus on handling the 1st, 2nd, and 3rd Layer of the Open Systems
Interconnection (OSI) standards. They are connected with category 5 (Cat5) cable and
run IEEE 802.3 protocol to manage packets and frame size. Wireless LANs run IEEE
802.1X protocol because of “vulnerability to over-the-air signal interception” [1].
Network speeds can range from 10 Mbps with IEEE 802.3 to 10 Gbps with IEEE
802.3ae. Network topologies that are used include Bus, Ring, and Star. The most
common topology in use is a combination of star and bus. The bus makes up the
backbone of the network with star networks branching out [2]. Switches, routers,
hubs/wireless hubs, and servers are components that a LAN can contain.
Underlying Technology - Components
Router
Routers make the connection to the Internet for LANs. They use a configuration
table to decide where packets should go. This table keeps track of which connections
lead where, priorities for connections, and rules for handling traffic. They keep
unnecessary packets from using up all the bandwidth and makes sure information meets
its destination [3]. Routers mainly deal with Layer 3 of the OSI protocol.
Hubs/Wireless Hubs
A hub is used to connect basic networks together. They are good for very small
networks and for shortening up distances packets have to travel. Hubs can be wireless
and allow wireless users to connect to the network. When transferring data between
points, hubs have to follow the Ethernet process called CSMA/CD as part of the IEEE
standards [4]. This process is used to communicate across the network in order to avoid
collisions of packets. The result is that hubs have the share the bandwidth with all the
devices connected to it. If too many hubs are connected to together then this will cause
problems for the network when large files are being transferred.
Switches
Switches connect the network and give the device connected to the switch port the
full bandwidth. A fully switched network completely replaces all the hubs and allows the
network to maintain full duplex. There are not too many people who use fully switched
networks because switches are much more expensive then hubs. LAN switches use
spanning-tree protocol (STP) that is part of the IEEE 802.1d specification to determine
the best path for data to take [2]. Three widely used configurations of LAN switches are
shared memory, matrix, and bus architecture. Switches are focus on layer 2 of the OSI
standard.
Servers
In order for a network to manage a large number of users it become necessary to
implement a server. A server is a high-powered computer connected to the network that
serves a special function for the network. For most LAN purposes a server serves as a
central point of information storage, file distribution and network managing [5]. A web
server connected to a LAN could allow users to login from the Internet to access files.
Small LANs do not necessary need a server because a router can handle managing a
small network.
Conclusions
A LAN consists of a group of computers and devices connected by switches and
hubs. For this LAN to gain access to the Internet it must contain a router. The speed of
the network greatly depends on the configuration of the switches and hubs. Servers can
provide specialized functions for the LAN network. There are other components that
LANs can contain like repeaters, buses, and gateways that help better connect networks
and solve other networking problems.
References
[1]
Neal Leavitt. (2008, March). Will IEEE 802.1X Finally Take Off in 2008?
Computer. [Online]. 41(4), pp. 12-13.
[2]
M. Palmer and R. B. Sinclair, Guide to Designing and Implementing Local and
Wide Area Networks, 2nd ed. Boston, Course Technology, 2003.
[3]
Jeff Tyson. (2001, 24 January). How LAN Switches Work. [Online]
HowStuffWorks.com. Available: http://computer.howstuffworks.com/lanswitch.htm
[4]
IEEE Standard for Information technology: CSMA/CD, IEEE Standard 802.3,
2005
[5]
Behrouz A. Forouzan, Data Communications and Networking, 3rd ed. New York,
McGraw-Hill, 2004.
[6]
S. Rose and A Nakassis. (2008, March-April) Minimizing information leakage in
the DNS. Network, IEEE. [Online]. 22(2), pp 22 – 25.