Mumbai University > Information Technology > Sem4 > Computer Networks

Marks: 5M

Year: May 2014

There are different types of Networks such as point to point, broadcast, multicast, unicast. Apart from this, networks can be broadly classified as PAN, LAN, MAN, WAN, Wireless Networks, Home Networks, Intranetworks and Internetworks.

• Local Area Networks (LAN)

  • These are privately-owned networks within a single building or campus of up to a few kilometer in size.

  • They are widely used to connect personal computers and workstations in company offices and factories to share resources (e.g., printers) and exchange information.

  • LANs are distinguished from other kinds of networks by three characteristics:

    (1) their size (2) their transmission technology and (3) their topology.

  • LANs are restricted in size.

  • LANs may use a transmission technology consisting of a cable to which all the machines are attached, like the telephone company party lines once used in rural areas. Traditional LANs run at speeds of 10 Mbps to 100 Mbps, have low delay (microseconds or nanoseconds), and make very few errors. Newer LANs operate at up to 10 Gbps.

  • Various topologies are possible for broadcast LANs.

• Metropolitan Area Networks (MAN)

  A metropolitan area network, or MAN, covers a city.

  Example of a MAN: The cable television network available in many cities.

  Cable television is not the only MAN. Recent developments in high-speed wireless Internet access resulted in another MAN, which has been standardized as IEEE 802.16.

• Wide Area Networks (WAN)

  • A wide area network, or WAN, spans a large geographical area, often a country or continent. It contains a collection of machines intended for running user (i.e., application) programs.

  • The hosts are owned by the customers (e.g., people's personal computers), whereas the communication subnet is typically owned and operated by a telephone company or Internet service provider. The job of the subnet is to carry messages from host to host, just as the telephone system carries words from speaker to listener.

  • Wireless Networks

  Wireless networks can be divided into three main categories:

  • System interconnection.
  • Wireless LANs.
  • Wireless WANs.

• Home Networks

  • The fundamental idea is that in the future most homes will be set up for networking. Every device in the home will be capable of communicating with every other device, and all of them will be accessible over the Internet.

  • Many networks exist in the world, often with different hardware and software. People connected to one network often want to communicate with people attached to a different one. The fulfillment of this desire requires that different, and frequently incompatible networks, be connected, sometimes by means of machines called gateways to make the connection and provide the necessary translation, both in terms of hardware and software. A collection of interconnected networks is called an internetwork or internet.