SLR 11/ Networks Flashcards
Define Peer-to-Peer networks
Each PC on the network has equal responsibility
No single point of failure
PCs not reliant on each other for resources
Generally easier to maintain and set up
Define Client-Server networks
One central server controls the network
Central point of failure
Network access centrally controlled
Generally more complex to manage
Many tasks can be handled by the server
Define Authentication
Require a username and password to log on
Multiple credentials
Smart cards
Define Proxies
Physical computers
Placed between the network and outside world
Traffic must pass through
Define Firewalls
Software and hardware
Isolate network traffic
Configured to allow or deny traffic in or out
Stateful packet inspection
Define Encryption
Encrypts traffic so it can’t be read without being decrypted. Data is encrypted and decrypted using a set of
keys.
Name the 4 methods of securing a network
Authentication
Proxies
Firewalls
Encryption
Factors for Dedicated Servers
There for Server farms in professional data centres.
Costly to set up and maintain.
Extremely reliable.
Low Latency
High performance
Factors for Listen Servers
Half-way between dedicated client-server and peer-to-peer. One client acts as a temporary server.
Dependent on speed of host internet connection.
Host advantage requires lag compensation.
Host migration if host leaves.
Factors for Peer-to-peer
All data is sent as raw streams to all other computers in the game.
No specialist infrastructure required.
Number of connections and players is limited.
Same latency for all players.
What are 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.
HTTP and POP3 are types of Protocols.
Name the Layers of the TCP/IP stack and protocol layering.
Stage 1 - Application Layer
Stage 2 - Transport Layer
Stage 3 - Network Layer
Stage 4 - Link Layer
What is Stage1 - Application Layer
The application layer is based at the top of the stack. It specifies what
protocol needs to be used in order to relate the application that’s being sent
What is Stage 2 - Transport Layer
The transport layer uses TCP to establish an end-to-end connection
between the source and recipient computer.
The transport layer splits data up into packets and labels these packets with
their packet number
The total number of packets the original data was split
up into and the port number being used for communication.
What is Stage 3 - Network Layer
The network layer adds the source and destination IP addresses. The
combination of the IP address and the port number is called a socket
address
What is Stage 4 - Link Layer
The link layer is the connection between the network devices, it adds the
MAC address identifying the Network Interface Cards of the source and
destination computers
What is LAN
Local Area Network. A LAN is a network spread over a small geographical area. Hardware usually owned by the person/business
What is WAN
Wide Area Network. a WAN is typically spread
over a large geographical area. Usually, a WAN will require extra telecommunication
hardware. Infrastructure used in WANs is owned by third-parties.
What is the DNS
Domain Name Server (DNS) is the system used to name and organize internet
resources. It is a hierarchy, in which each smaller domain is separated from the larger
domain by a full stop.
What is a Data Packet
Packets are segments of data
Explain the process of a data packet.
- Header. Contains the sender and recipient IP addresses
- Protocols Being used. Allows the recipient to understand the packet
- Order of packets. Packets reconstructed in order
- Time to Live. Tells the packet when to expire so it doesn’t travel forever
What is the Payload
Raw data to be transmitted
What is Packet Switching
Packet switching is a method of communication in which data is communicated using
packets across a network. In this method of communication, packets are sent across the
most efficient route, which can vary for each packet.
Advantages and Disadvantages of Packet Switching
Advantages: Multiple methods to ensure data arrives intact. Multiple routes can be used between
devices, so if one path breaks, another
can be used
Disadvantages: Time is spent deconstructing and
reconstructing the data packets. Must wait for all packets to arrive before
data can be received.
What is Circuit Switching
Circuit switching is a method of communication where a direct link is created between two devices. This direct link is maintained for the duration of the entire conversation between devices. Circuit switching requires the two devices to transfer and receive data at the same rate.
Advantages and Disadvantages of Circuit Switching.
Advantages: Data arrives in a logical order which results in a quicker reconstruction of the data. Enables two users to hold a call without delay in speech.
Disadvantages: Bandwidth is wasted during periods of
time in which no data is being sent. Devices must transfer and receive data at
the same rate. Using switches means electrical
interference may be produced which can
corrupt or destroy data.
What are Proxy servers
A proxy server acts as an intermediary, collecting and sending data on behalf of the user.
There are several benefits of using proxies:
1. The privacy of the user is protected and they remain anonymous
2. The proxy server can cache frequently used website data making it faster to load
3. Proxies can reduce overall web traffic
