Section 10 Chapter 57 - Packet switching and routers

Question 1

Packet switching

Answer 1

The method of communicating packets of data across a network where other communications are happening simultaneously

Question 2

Structure of a packet

Answer 2

Header - Payload - Trailer

Question 3

Contents of the header (5)

Answer 3

• Senders IP address
• Recipients IP address
• Protocol
• Packet number
• Time to live (time before it expires)

Question 4

How packets are routed through the internet

Answer 4

Each packet will be sent along the path that is at that moment the least congested. Packets may arrive out of order and some may be missing, but the receiver can put them in order and request any that were lost

Question 5

Router

Answer 5

A device that is used to connect networks

Question 6

Hop

Answer 6

A traversal between two routers

Question 7

Job of the router

Answer 7

Read the recipients IP address of a packet and send the packet along the least congested route do its destination

Question 8

Why routers that are connected to the internet have to be registered

Answer 8

Because the IP address will have to be unique over the whole internet

Question 9

Gateway

Answer 9

Performs the same task as a router but is used if the network it is receiving from uses a different protocol to the network it is about to traverse through. The gateway strips away the header and replaces it with one according to the new protocol