Computer communications and networking Flashcards
What is a network?
A collection of connected computers plus their peripherals
What is a device on a network called?
Node
What is a LAN?
Local area network
What is a WAN?
Wide area network
Advantages of a LAN
- Makes data sharing easier
- Makes backups easier
- Computers are easily updated/reconfigured
- Computers can be monitored easily
- Users can communicate with each other
Disadvantages of a LAN
- Specialist staff needed for maintenance
- Network problems could affect all users
- Security may be a problem because data is accessible from many places
Differences between a LAN and WAN
- A LAN is confined to one site
- A LAN is owned and maintained by a single organisation but a WAN may not
What is a network interface controller (NIC)?
A device that generates and receives suitable electrical signals. It holds the MAC address of each node.
What is a MAC address?
Media access control address.
Allows a node on a network to be identified.
What are fibre-optic cables?
Cables that transmit data using light waves
What is a network hub?
Hardware that connects many network devices together into a single network segment.
A signal arriving at one is transmitted to all others
What are switches? (No, not the lightbulb switches)
Devices that connect multiple network segments or devices.
Messages are only sent to the intended device
What is the difference between hubs and switches?
Hubs transmit a message to all devices connected to it
However
Switches transmit a message to an intended device
What are bridges?
Devices that connect more than one network together
What are wireless access points?
Devices often connected to a router which allow a connection to a LAN without the need for cables
What features do wireless access points have to protect them from security risks?
- encryption
- hiding their broadcast identities
- allowing access to only certain MAC addresses
What is a router?
A device that receives data in the form of packets and forwards them to their destination.
What is a client-server network?
Where one or more servers provide services to many client machines where the users work
What is a server?
Computers that handle network functions
Types of servers
- database server
- file server
- mail server
- print server
- web server
- gaming server
What is a peer-to-peer network?
Where each computer in the network carries out the needs of the user as well as carrying out network functions
Disadvantages of peer-to-peer networks
- maintenance is more difficult than with a client-server network
- security is poor
- tend to be slow due to the amount of multitasking
Advantages of a peer-to-peer networks
- easy to set up
- files can be shared directly between users without the need to go through web servers
What is the advantage of a client-server network?
The network functions are handled by dedicated machines and clients can provide for the immediate needs of the users
What is a network topology?
The layout of the network components; cabling and position of the nodes
What does a bus topology look like?
The computers and other devices are attached to a single backbone.
[INSERT BUS TOPOLOGY DIAGRAM]
Advantages of a bus topology
- easy to set up
- cheap
Disadvantages of a bus topology
- problems with the backbone can bring the whole network down
- can only cover a limited distance
- many data collisions can slow the network down
What does a star topology look like?
Client machines are connected to a central hub or switch which is usually connected to a server.
[INSERT STAR TOPOLOGY DIAGRAM]
Advantages of a star topology
- robust - problems with a connection do not affect the whole network
- fewer data collisions than bus so faster
Disadvantages of a star topology
- needs more expertise to maintain
- can be expensive to set up - more network hardware and software needed
What does a ring topology look like?
Data passes through each node, carried in data units called tokens
Advantages of a ring topology
- very fast - no collisions
Disadvantages of a ring topology
- problems with the backbone can bring the whole network down
- data passes through every node - network vulnerable to malfunctions
What is a protocol?
A set of rules that covers data communications
Allows different networks and devices to talk to each other
What is the de facto standard for data transmission over the Internet?
Transmission Control Protocol/Internet Protocol
TCP/IP
What is a host?
A computer system that is accessed remotely and holds data or other facilities such as web servers
What are packets?
Collections of data forming part of a message
What is IP concerned with?
The construction of packets
What is TCP concerned with?
The connection of hosts
What is packet switching?
Packets from a particular message may take different routes according to availability and traffic conditions, and form a complete message at the receiving end
What is the advantage of packet switching?
It improves the reliability of sending messages because of one route is down or congested, another can be found
What is an IP (Internet Protocol) address?
A 32-bit number so computers can be identified on a network
What is static addressing?
Permanently allocated IP addresses
What is dynamic addressing?
IP addresses that can be changed- a computer may not always have the same IP address
What is a MAC (Media Access Control) address?
A unique number number stored in each NIC so it can be used to inset icy a device on a network
