4.9.3 The Internet Flashcards
What is the internet?
A network of interconnected computer networks which uses an end to end communication protocol.
What is a protocol?
Set of rules that allows for communication between devices.
What kind of network is the internet?
A wired network.
What is an internet service provider?
A company that provides its customers with access to the internet.
What are national companies?
The largest internet service providers.
National internet service providers.
What do national internet service providers do?
National internet service providers provide internet access to smaller regional and local ISPs, from whom homes and businesses can buy access to the internet.
What is a packet?
A container in which data is transmitted over networks.
What are packets labelled with?
Addresses for their sender and recipient and contain information intended for the recipient.
What is a packet switched network?
- One in which data is sent in packets.
- One message is frequently split into multiple packets, each of which is sent to its recipient via the best possible route before being reassembled with other packets by its recipient.
What happens when a packet is sent through a network?
• It usually has to pass through a number of routers before reaching its destination.
How does the router use the address?
• It uses the recipient address on a packet to determine where to send the packet.
What is a hop?
Every time that a packet passes through a router.
What is a packets time to live?
• Each packet can only pass through a finite number of hops.
A packets time to live is a number that indicates how many hops the packet can partake in.
How is the packets TTL affected by hops?
A packets TTL is reduced by one with each hop.
What happens when a packets TTL expires?
- When a packets TTL expires, the packet is said to be dropped. The packet is deleted.
- The recipient will notice a missing packet and request that the sender transmits the missing packet again.
