TCP/IP

Question 1

What are the 4 layers?

Answer 1

1) network access
2) internet
3) transport
4) application

Question 2

What does the Network access layer do?

Answer 2

• deals with pure hardware (wires, satellite links, network interface cards)
• access methods such as CSMA/CD ( carried sensed multiple access with collision detection)
• ethernet exists at the network access layer, its hardware operates at the physical layer and its medium access control method operates at the datalink layer.

Question 3

What does the internet layer do?

Answer 3

• responsible for the routing and delivery of data across networks.
• allows communication across networks of the same and different types.
• carries out translations to deal with dissimilar data addressing schemes
• IP and ARP are both to be found at the internet layer.

Question 4

What does the transport layer do?

Answer 4

• TCP: reliable, connection-oriented protocol that provides error checking and flow control through a virtual link that it establishes and finally terminates
• Examples include FTP and email.
  -UDP (user datagram protocol): unreliable, connectionless protocol that doesn’t error check or offer any flow control. Examples include SNMP.

Question 5

What does the application layer do?

Answer 5

• If it gives an application access to the communication environment.
• e.g. Telnet, HTTP, SMTP