What is the internet?
interconnected group of computing devices that uses open protocols to standardize how information is sent and received across our planet
What is the relationship between servers and clients?
clients request information that exist on servers
What is defined by protocols?
form of the client request, and how it is sent through the network
What is a server?
computer connected to internet that responds to requests – machine that ‘serves’ content
What lives in server?
HTML (or other website info)
Server Example
canvas.ubc.ca
NO ‘WWW’
What is a file server?
machine that serves up files
ie. machine www.cs.ubc.ca lives in ICICS/CS building
this machine is networked with a file server, which allows different machines on cs.ubc.ca network to access same files
What do most interactions over the internet use?
client/server interaction protocol
What is the client/server interaction protocol?
What is synchronous communication?
both sender and receiver are active at same time (ie. talking on telephone)
What is asynchronous communication?
sending and receiving occur at different times (ie. email, answering machine)
Can servers handle many clients at a time?
yes – server is busy only for as long as it takes to perform your request
ie. between two consecutive client requests from your browser (getting page, and asking for another), that server could have serviced hundreds of other clients
What is data transmitted via?
open protocols
What do protocols do?
standardize communication, so all data is sent by same rules for sending and receiving data
What are open protocols?
protocols available for use by anyone to ensure that anyone can build systems that connect to internet
What are two of the most important protocols?
- internet protocol (IP)
TCP/IP
How do packets travel?
TCP/IP
What information do packets hold?
TCP/IP
Why is each packet independent?
because each packet can take different route – congestion and service interruptions do not delay transmissions
How does TCP/IP protocol work under adverse conditions?
if traffic is heavy and pack progress is slow, protocol allows packet to be thrown away
What do routers do?
perform traffic directing functions on internet
In what form is data sent through internet (such as webpage or email)?
data packets
Where do packets travel?
forwarded from one router to another router through networks that constitute an internetwork until it reaches its destination node – routers direct the packet through the network to the server with the given IP address