Saturday, 7 April 2012

Week 4- Typology, Protocol and Architecture

Today, we learn about typology, protocol and architecture. Typology can be classified into two; 
Physical and Logical typology.

Physical Typology- mapping of links and notes into a geometrical     shape.

Logical Typology- mapping of the flow of data.

Physical typology can be classified into five types

  • linear bus
  • ring
  • star
  • star -wired ring 
  • tree
Linear bus typology consist of a main cable and terminator at both end. All notes is connected to the main cable. Linear bus typology is easy to be connected and need less wire but may the whole system may malfunction if the main cable is broken. Ethernet and local talk uses linear bus typology.

Ring typology is similar to linear bus in many aspects. The only difference is that bus typology do not have terminator as all notes is interconnected with each other. 

Star typology is designed so that each nodes is connected to a hub/concentraterEthernet and local talk uses linear bus typology . Star typology is easy to add new nodes and will not malfunction if one of the nodes breaks down. However, it need more cable length and cost more compare to linear bus. 

Star-wired is externally same as star typology. Internally, the MAU (multiststion access unit) allows the information to pass from a device to a ring or circle. The Token Ring uses star- wired typology.

A tree topology combines characteristics of linear bus and star topologies. It consists of groups of star-configured workstations connected to a linear bus backbone cable. Tree typology allows point to point wiring for each nodes but  the overall length of each segment is limited by the types of cable used. 

In this lesson, we also learn about protocols. Protocols is a set of rules that governs the communication the computers in a network. It can be divided into
  1. Ethernet
  2.  Localtalk
  3. Token Ring
  4.  Fiber Distributed Data Interface (FDDI )

We also learn about the types of architecture:
  • Peer to peer 
  • client/server

In peer to peer, all computers are considered equal and have the same tendency to share information . Peer to peer network lacks security as there is no central computer to control the network.

In client/ server network, there are a central network that governs the transfer of data between the computers. The server is the heart of the system , providing security and access to information.  

Lastly, our homework of the day is to find out the definition of Asynchronous Transfer Mode (ATM)  . It encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that use variable sized packets or frames.  

That's all from me this lesson. Thanks 4 spending time to read it ^^


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