4.9.4.1 TCP/IP Flashcards
Application
Layer the user interfaces with
Selects appropriate protocols for transmission
Use appropriate protocols
Interface with user
Transport
Splits the data into packets
Numbers the packets into header e.g ⅔
Establishes and maintains connection, e.g handshaking protocol, end-to-end principle states how the sender and receiver will communicate
Deals with errors, resends packets
Reorders packets
Packet requests / responses
Network
Looks at destination IP address
Adds destination / source IP
Router decides upon next appropriate hop after looking at IP address
Can split / combine / resize packets if required
Error checking / detection
Encryption for wireless
Tunnelling through firewalls
Remove IP addresses
Link
Adds sender and receiver MAC addresses
Transmit the data, convert data into electronic signal or radio wave, completed by NIC
responsible for network drivers // physical connection // changing from one medium to another
Remove MAC addresses
Receive transmitted data
What are sockets?
A socket is the combination of IP address plus port, e.g 192.168.0.3:80
A connection between two computers uses a socket.
What is a MAC address?
A unique address assigned to a network card so that Each piece of networking hardware has a unique identifier
Whitelist MAC addresses that are trustworthy
Blacklist MAC addresses you don’t want to connect
Explain what the well-known ports and client ports
are used for and the differences between them.
53 - DNS (Domain Name System)
80 - HTTP (HyperText Transfer Protocol) - used for transferring web pages
Why is TCP/IP structured in layers?
People developing only have to understand the layer they are operating on.
What layer does the router operate on?
the network layer - when receiving data it doesn’t go further than checking the ip addresses and forwarding it
