4.1 Fundamentals of Computer Networks Flashcards
Explain how TCP/IP layers help to fulfil the purpose of the TCP/IP model.
The TCP/IP model is a suite of communication protocols that dictate how devices exchange data with one another in a network. The TCP/IP model is broken down into TCP/IP layers for specialisation so that the complexity of the TCP/IP model can be simplified.
What is the purpose of the application layer?
The application layer defines the format of the data that is to be transmitted.
What is the purpose of the transport layer?
The transport layer determines the mode of data transmission.
At the transport layer, the OS breaks up the data into segments and encapsulates each segment into a TCP or UDP packet. The source and destination port are added to the packet header.
Waht is the purpose of the internet layer?
At the internet layer, the OS adds the source and destination IP addresses to the IP header.
Describe the use of switch and router in the TCP/IP network.
At the Network Access layer, the switch sends the ethernet frame to the designated machine in the local network based on the MAC address.
At the Internet layer, the router sends the IP packet to the designated host in the network based on the IP address.
Describe how data is transmitted in a packet switching network.
Data will be broken up into packets before the data is sent into the network. The data packets move from one node to another in a network as each packet may go by a different route to its destination.
Explain two advantages of packet switching over circuit switching network.
If any segments of the network is disrupted, data packets can be routed around the disruption to other segments of the network since there is no dedicated path of transmission unlike in a circuit-switching network where data cannot be routed out of its dedicated path of transmission to other segments of the network.
A packet-switching network is more secured since it will be harder to attack all the transmission paths available instead of one dedicated path of transmission in a circuit-switching network.
Describe how a digital signature can be used to give confidence that a received message has not been altered.
The sender uses a hash algorithm to create a hashed version of the received message.
The sender then uses its private key to encrypt the hash to the digital signature.
Both the message and digital signature is sent to the receiver.
The receiver uses the sender’s public key to decrypt the digital signature back to the sender’s version of the hash.
The receiver then uses the same hash algorithm to create a new hash from the received message.
If the two hashes match, it means that the received message has not been altered.
