1.3.3 Networks Flashcards
(9 cards)
Network
The name given to two or more computers connected together with the ability to transmit data between each other.
There are two main types of networks:
-Local area network
-Wide area network
Local Area Network (LAN)
The name given to a network which is spread over a small geographical area or a single site.
Wide Area Network (WAN)
A network which is spread over a large geographical area.
Two types of network
Physical topology - the physical layout of the wires and components which form the network. (bus, star and mesh)
Logical topology - the layout which shows how data flows.
Physical Bus topology
In a bus topology all terminals (devices) are connected to a backbone cable , the ends which are plugged into a terminator which absorbs the signals when they reach the end, to prevent interference.
Advantages:
-Relatively inexpensive to setup
-does not require any additional hardware
Disadvantages:
- If backbone cable fails all the terminals(devices) get disconnected. The entire network gets disconnected
- As traffic increases performance decreases
-All computers can see the data transmitted making it not secure..
Physical Star topology
Star topology uses a central node usually a switch to direct data through the network. MAC address which are unique to each device are used to identify each device on the network.
Advantages:
-Performance stays consistent even with heavy network traffic
-If one cable fails only the terminal that was connect to it will disconnect to the network
-Transmits data faster giving better performance than bus topology.
-Easy to add new stations(devices to the network by adding cable)
-No data collisions
Disadvantages:
-Expensive due to switch and cabling
-If the central switch fails the rest of the network fails.
Physical mesh topology
In a mesh topology every node is connected to every other node. Mesh topology is usually found in wireless technology such as wi-fi.
Advantages:
-If using a wireless network there is no cable cost
-As the number of nodes increases the reliability and speed of network becomes better.
-Nodes are automatically incorporated
-Nodes do not go through a central node which increases the speed.
Disadvantage:
-If using a wireless network, devices
with wireless capability (which
increases cost) must be purchased
-If using a wired network, a large
quantity of cable is required
compared to other network
topologies like bus and star. This is
expensive
-Maintaining the network is difficult
Protocols
A protocol is a set of rules defining how two computers communicate with each other.
Protocols are standard so that all devices have a designated method of communicating
with each other, regardless of manufacturer.