Net: Ch1-8

Question 1

List the Basic Purposes of Computer Networks

Answer 1

• Communication network: Enabling all types of communication, e.g. e-mail
• Data network: Access to geographically distributed data, e.g. customer database
• Functional network Extension of the possibilities by including special ones
• Computer and hardware components, e.g. color laser
• Load sharing: Distribution of loads at peak times
• Availability network: Ensuring availability even if a computer fails
• or systems
• Performance network: computationally intensive problems are distributed over several computers

Question 2

Define and Explain Topology

Answer 2

The physical topology is the configuration of the network nodes and connections. the
possible logical connections of network nodes is referred to as logical topology. In doing so
specifies which pairs of nodes can communicate with each other and whether they are directly physically connected to each other
are connected. The physical and logical topologies do not have to be identical in networks.
Performance and stability parameters can already be derived from the network topology:
Possibilities and behavior for or when scaling the network as well as the costs incurred,
Network reaction to the failure of stations or lines,
Number of lines that are allowed to fail without removing a station from the network connection
is completed
Methods for path finding (routing),
Necessary protocol overhead for error-free communication.

Question 3

Types of topology and examples:

Answer 3

• Bus CLAN) half - duplex
• Token-Ring CLAN) half-duplex
• Star (LAN) full duplex
• Tree (WAN)
• Mesh-Network CWAN)

Question 4

What is a Bus network? What are the advantages and disadvantages?

Answer 4

• Bus CLAN) half – duplex
  With the bus structure, all subscriber stations are connected to a common transmission medium
  connected. Stations can be added or removed at will. The transfer takes place
  with this topology directly from the source to the destination. The advantages of the bus topology are that it is light
  Expandability, modularity, easy implementation and decentralized control. disadvantageous
  are the susceptibility to failure of the medium, the lack of security against eavesdropping and possible
  unpredictable waiting times.
  Advantages:
  ➢ No routing necessary (path search).
  ➢ Easily expandable as it can be coupled passively.
  ➢ If a node is added, the cabling effort is low.
  Disadvantage :
  ➢ The length of the bus is limited

Question 5

What is a token ring? Advantages? Disadvantages?

Answer 5

• Token-Ring CLAN) half-duplex
  The information is transmitted in a specified transmission direction. Typically, the
  Access to the transmission medium sequentially from station to station. The message gets to everyone
  Stations serially over. Ring topologies are easily expandable and have a low number of lines.
  Disadvantages arise with line or station failure and with the duration of the message transmission
  proportional to the number of stations connected.
  Advantage:
  ➢ No routing necessary (path search).
  ➢ Each node (N) is connected to a neighboring node.
  ➢ If a node is added, the cabling effort is low.
  Disadvantage :
  ➢ If a connection is lost, communication in the ring is no longer possible.

Question 6

What is a Star Network? Advantages Disadvantages?

Answer 6

• Star (LAN) full duplex
  In the star topology, the transmission stations are star-shaped to a central node
  connected. The data can only be exchanged indirectly via the central node.
  A distinction is made between active and passive star systems. In active star systems, the mean
  Node a computer that takes over the forwarding of the messages. Its efficiency
  determines the performance of the network. Passive star systems have only one node in the middle, which
  ways summarized. This node does not take over any switching tasks, but only serves
  the signal regeneration.
  Advantage:
  ➢ No routing necessary (path search).
  ➢ Each node (N) is directly connected to the central station.
  Disadvantage :
  ➢ If the central station fails, communication is no longer possible

Question 7

What is a Tree network? Advantages? Disadvantages?

Answer 7

• Tree (WAN)
  The tree topology is characterized in that, starting from a root, a set of
  Branches to other nodes exist, which again are the same except for the last level (“leaves”)
  build up a basic structure with further branches. Previous broadband networks had one
  Tree structure because you could attach a central converter/amplifier to the root. modular
  modern networks, based on structured cabling with a hub hierarchy, also have
  a tree structure. This structure is well suited for cabling across the board or for networks in
  multi-storey buildings. Tree topologies are used in broadband networks (IEEE 802.4) and in Metropolitan
  Area Networks (MAN IEEE 802.6) used.
  Advantage:
  ➢ Easily expandable.
  ➢ No routing necessary (path search).
  Disadvantage :
  ➢ none

Question 8

What is a Mesh Network? Advantages? Disadvantages?

Answer 8

• Mesh CWAN)
  Wide area networks are designed for voice or data transmission over long distances. these nets
  are set up across the board in all industrialized countries and can be used without restriction for business
  and private communication can be used. The internet is meshed
  Sectional networks, their switching computer, also called node computer, with several others
  node computers are connected. In this network structure, the data in the form of data packets
  passed on from one node computer to the next node computer through the network.
  Network structure
  The physical topology is the configuration of the network nodes and connections. the
  possible logical connections of network nodes is referred to as logical topology. In doing so
  specifies which pairs of nodes can communicate with each other and whether they are directly physically connected to each other
  are connected. The physical and logical topologies do not have to be identical in networks.
  Performance and stability parameters can already be derived from the network topology:
  Possibilities and behavior for or when scaling the network as well as the costs incurred,
  Network reaction to the failure of stations or lines,
  Number of lines that are allowed to fail without removing a station from the network connection
  is completed
  Methods for path finding (routing),
  Necessary protocol overhead for error-free communication.
  Advantage:
  ➢ Easily expandable.
  Disadvantage :
  ➢ Routing necessary (path search).

Question 9

Transmission Techniques: What are they? Where are they used? Examples?

Answer 9

Parallel data transfer -all 8 bits are transmitted with one clock.
Typical parallel interfaces:
➢ LPT
➢ SCSI
➢ PCI
➢ AGP
➢ Data, address and control bus
Advantages:
 Fast data transfer
Disadvantage:
 high cable expenditure

Serial data transmission -1 bit is transmitted with one cycle.
Typical serial interfaces:
➢ USB
➢ PS2
➢ COM
➢ FireWire
➢ serial ATA
Advantages:
 low cabling costs
Disadvantage:
 slow data transfer