Datakommunikasjon

Question 1

What is a host?

Answer 1

A host is a device that is connected through the internet, also known as end-systems.

Question 2

What is a packet switch?

Answer 2

A router or switch that forward packets through the internet.

Question 3

What is a packet?

Answer 3

A chunk of data.

Question 4

How does devices communicate through the internet?

Answer 4

Through communications links, i.e. fiberoptics or copper cables, radio and satelite communications.

Question 5

How is the internet structured?

Answer 5

A collection of devices routers and switches are linked through local networks to local and/or regional ISP’s, that are again linked to content provides and datacenter networks. A network of networks.

Question 6

What are Internet Protocols, and why are they important?

Answer 6

Internet Protocols are a set of standardized rules that enable communication between devices on a network. They define how data is formatted, transmitted, routed, and received to ensure reliable and efficient communication over the Internet.

Question 7

How are Internet Protocols layered, and what are the key layers?

Answer 7

1. Application Layer: Interfaces with applications and provides protocols like HTTP, FTP, DNS, and SMTP for user services.
2. Transport Layer: Ensures reliable communication (TCP) or faster, connectionless communication (UDP).
3. Internet Layer: Handles addressing and routing of data using protocols like IP, ICMP, and ARP.
4. Network Access Layer: Manages the physical transmission of data over network hardware (e.g., Ethernet, Wi-Fi).

Question 8

What happens when a host sends a packet over the Internet?

Answer 8

Application Layer: The host’s application generates data (e.g., an HTTP request).
Transport Layer: The transport protocol (TCP/UDP) adds a header with port numbers and, in the case of TCP, additional information for reliable delivery.
Internet Layer: The IP protocol adds an IP header containing source and destination IP addresses.
Network Access Layer: The data is encapsulated into frames, which include hardware (MAC) addresses, and sent over the physical network.
Routing: Routers use the destination IP address to forward the packet toward its target.
Delivery: At the destination, the process is reversed to extract the original data.