Chapter 13: Networks Flashcards
What protocol does the internet layer use?
IP
What protocol does the transport layer use?
TCP
What is the 4 layers in order (Network/Data link access, Internet layer, application layer, transport layer)
- Network/ Data link access
- Internet layer
- Transport layer
- Application layer
What does the TCP do?
Sending: Divides data into packets, adds sequence numbers and sends any errors
Receiving: Checks for missing packets and asks them to be resent. Checks for errors in packets and asks for them to be reset, using sequence numbers to reassemble data
What does the IP do?
Sending: adds destination address to packets, adds
source address
Receiving: Accepts packets with its own address attached, ignores packets without it
What are the advantages of packet switching
- If there are errors the whole message does not have to be resent
- Data can be sent even if there is a lot of traffic
- Always picks the least congested path
- If one router is broken another route can be found
What are some threats to network security?
- Social engineering: Going to a human and convincing them to allow access threats, bribes etc.
- Malware: Software designed to harm the network
- DDoS: Distributed Denial of Service. Attackers send packets that make no sense to a server. The server is forced to try and understand this which slows down or crashes the server
- SQL injections: Inputting special code that can reveal confidential information.
- Brute Force: Trying every letter and number combination to guess a password
What information do packets store?
Source Address - Where it’s from
Destination Address - Where it’s going
Sequence number - So it can reassemble in order
What is a WAN?
WAN: Wide area network (connects several LANs over a large geographic area)
What is a LAN?
LAN: Local area network (Connects sites such as schools and offices)
What is a PAN?
PAN: Private area network (connects devices that are up to 10 metres away from each other, Bluetooth is an example)
What are the two network TYPES?
Client server: 2 types of computers, server (Where all the data is stored and keeps the network secure) and clients (the computers used to work or whatever you are doing)
Peer to Peer (p2p): All computers are connected to each other and no one has authority. Each computer acts as both a client and a server.
What is a NIC?
Network interface card: Formats data in into the required format specified by the network protocols
What are the advantages and disadvantages of a Star Topology
Advantages:
- Adding and removing devices are easy
- If one link fails the others will still work
- Data can be sent to the intended node without having to go through any other devices
Disadvantages:
- If the central point fails the whole system fails
- Requires a lot of wiring
