5. 6. 7. The Internet Flashcards
What is the internet?
A network of networks
A centralised system would guarantee unique identifiers, why is this not appropriate?
Single point of failure and isn’t scalable
Describe a MAC Address
A name rather than an address
Unique name for each device in a network
48 bit number (24 bit unique identifier, 24 network interface controller)
Establishes local network
Hidden
Used to differentiate between machines on same LAN
How are MAC addresses generated?
Distributed to device providers
Describe an IP address
Internet Protocol Address
32 bit number AA.BB.CC.BB
Hierarchical
Gives physical address- mechanism for routing data
identifies a server of service on the internet
What is DNS?
Domain name space. The domain name system is a DS built on top of the internet. Used to create associations between human-readable names and IP addresses.
A hierarchy of servers.
What is the difference between DNS and MAC/IP?
DNS is a live piece of internet infrastructure. A hierarchy of servers with the most authoritative at the top.
How does DNS behave as a cache?
we ask ISP for a web address, if it doesn’t know its DNS server communicates with next level up in the hierarchy.
Bottom layer remembers the answer for future.