T3 - LANs and WANs: Flashcards
Internet
- is a collection of inter-connected networks
Largest WAN
WAN
- Any network in which the computers communicate using resources supplied by a ‘third party carrier’ such as BT
-Covers a large geographical area
wans use
uses cables, telephone lines, satellites or radio waves to connect two or more remote locations
IPv4 addresses are
four 8-bit numbers (0-255) separated by dots
Newer IPv6 addresses are
128-bit numbers represented in hex
WAN stands for
– Wide Area Network (large geographical area)
Packet –
one unit of data sent through an IP network
Routing –
directing IP packets to their destinations
DNS stands for
– Domain Name System
IP address –
Internet Protocol address. Where packets of data are sent to or received from
MAC address
– Media Access Control address. The unique identifier of each device (or network interface card)
Packet switching:
file is broken up into data ‘packets’
packets contain info on
The IP address it is going to
The IP address it has come from
The sequence number of the packet
The number of packets in the
whole communication
Error checking data
Data Packets:
contain the same number of bytes
packets may flow through the Internet via different routes
marked with the packet number = can be reordered and checked for errors
Routers
- any node that can route packets from one place to another
IP address: dynamic IP address
- IP addresses will change when the router reconnects to the Internet.
actual geographical location of a networked device can be determined by this
Network interface card
- built into every networked device
Domain Name System (DNS) description
made up of domain names
Refers to IP address
A DNS server translates
a web address into an IP address
13 DNS root servers worldwide which
keep a complete database of all domain names and IP addresses
how many DNS root servers
13
When a DNS server receives a request not in its database,
it will pass the request on to another server until it reaches one with the matching name and IP address