CMPT 165 Lecture Notes - Lecture 3: Simple Mail Transfer Protocol, Hypertext Transfer Protocol, Https
18 Oct 2018
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Lecture 3
Structure of internet
• Some connections are faster and choose faster routes than others
• Gateway can be thought of as a more powerful network device
• Servers are just another computer equipped with more powerful hardware and software
(deals with lots of requests coming in for web files)
o Need more sophisticated software to deal with high requests
• To make requests you open your browser (software)
o You are looking for a file stored on another more powerful computer
o The request is made and the router finds the best path to relay the request to the
destination
o It may travel through other computers before it gets to your computer
o The server retrieves the file on it’s hard drive and sends it off
Protocols:
• A set of rules - can be anywhere (work rules, etc.) - equivalent to rules
• IP = Internet protocol - helps relay data between computers - essentially an address
o When mailing something you need an address for the destination of the mail
▪ Internet uses IP as the address for data to be sent to
▪ Which path to take to your computer/server
Other protocols
• TCP/IP
o Helps devices communicate (not really necessary to know)
• HTTP - hypertest transfer protocol
• HTTPS - secured version of HTTP
• FTP - file transfer protocol
o For transfer of files
• SFTP: Secured file transfer protocol
o Might involve asking for passwords to log in/transfer data
o Some sort of authentication process for security reasons
• SMTP: Simple mail transport protocol
o Used by email clients
How to identify the right computer
• IP address comes is sections of 8 bits
o 4 8-bit numbers
Document Summary
It may travel through other computers before it gets to your computer: the server retrieves the file on it"s hard drive and sends it off. Protocols: a set of rules - can be anywhere (work rules, etc. ) Ip = internet protocol - helps relay data between computers - essentially an address: when mailing something you need an address for the destination of the mail. Internet uses ip as the address for data to be sent to: which path to take to your computer/server. Url: uniform resource locator: when you type in a url you are really asking for a resource - a file (an html page, under www. sfu. ca (an ip address of a sfu server) Markup: web documents need to have structure in the document. Important elements: content, meaningful to audience, good grammar, etc, structure, gives a way to navigate your document, gives meaning to each element, markup, i. e. xhtml.
