COMP 2057 Lecture Notes - Lecture 3: Telnet, Plaintext, Hypermedia
27 Jun 2018
School
Department
Course
Professor
1
60-205 – INTRODUCTION TO THE INTERNET
WEEK #3 – INTERNET PROTOCOLS & HTML
Contents
Dr. Stephanos Mavromoustakos
find more resources at oneclass.com
find more resources at oneclass.com
2
WEEK #3 – INTERNET PROTOCOLS & HTML
Learning Objectives
This week, students should be able to:
Explain Internet Protocols
Discuss internetworking concepts related to Internet
Apply HTML code for designing basic HTML pages
THEORY – INTERNET PROTOCOLS
In life, protocols define the way we interact with other people - for example, the way we behave in a
public place. In computer science, protocols are formal sets of rules that dictate the ways in which
computers communicate with one another over a network medium. Protocols constitute the backbone
of networking. The standard model for networking protocols and distributed applications is the
International Standard Organization's Open System Interconnect (ISO/OSI) model. The Internet
protocol stack TCP/IP (Transmission Control Protocol/Internet Protocol) model presents a group of
protocols optimized for inter-computer communications and in particular for communications between
multiple applications that may run on one computer. Last week we briefly introduced both models. This
unit provides an overview of the TCP/IP stack and its different layers, identifies the function of each
layer, introduces the basics of how computers talk to one another in cyberspace using TCP/IP protocols,
describes the techniques for wide area networks, and discusses common transmission media for the
Internet.
TCP/IP Model – Transmission Control Protocol / Internet Protocol
Last week we briefly explained the 2 models as shown below.
OSI Model The TCP/IP Model
Layer 7 - Application Application Layer
Layer 6 - Presentation
Layer 5 - Session
Layer 4 - Transport Transport Layer
Layer 3 – Network Internetwork Layer
Layer 2 – Data Link Physical Layer
Layer 1 – Physical
Dr. Stephanos Mavromoustakos
find more resources at oneclass.com
find more resources at oneclass.com
3
The TCP/IP Model
TCP/IP Layer Function Example Protocols
Application
Layer
Represents data to the user and controls
dialogue
DNS, Telnet, SMTP, POP3, IMAP,
HTTP, FTP, SSH, SNMP, DHCP
Transport Layer Supports communication between diverse
devices across diverse networks
TCP, UDP
Internetwork
Layer
Determines the best path through the
network
IP, ARP, ICMP
Physical Layer Controls the hardware devices and media
that make up the network
Ethernet, DSL, Frame Relay
Below, we explain some of the above protocols:
DNS
The Domain Name System (DNS) is a hierarchical decentralized naming system for computers, services,
or other resources connected to the Internet or a private network. It associates various information
with domain names (e.g. www.uwindsor.ca) assigned to each of the participating entities. Most
prominently, it translates more readily memorized domain names to the numerical IP addresses needed
for locating and identifying computer services and devices with the underlying network protocols.
An often-used analogy to explain the Domain Name System is that it serves as the phone book for the
Internet by translating human-friendly computer hostnames into IP addresses. For example, the domain
name www.example.com translates to the addresses 93.184.216.119. Unlike a phone book, DNS can be
quickly updated, allowing a service's location on the network to change without affecting the end users,
who continue to use the same host name. Users take advantage of this when they use meaningful
Uniform Resource Locators (URLs), and e-mail addresses without having to know how the computer
actually locates the services. [ Ref. https://en.wikipedia.org/wiki/Domain_Name_System ]
Uniform Resource Locator (URL)
URL is an identifier for the location of a document on a web site.
An example of a basic URL:
http://www.aw-bc.com/info/regesstepp/index.html
~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~
protocol host path
upon entering this URL into the browser, it would:
oask the DNS server for the IP address of www.aw-bc.com
oconnect to that IP address at port 80
oask the server to GET /info/regesstepp/index.html
Dr. Stephanos Mavromoustakos
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Apply html code for designing basic html pages. In life, protocols define the way we interact with other people - for example, the way we behave in a public place. In computer science, protocols are formal sets of rules that dictate the ways in which computers communicate with one another over a network medium. The standard model for networking protocols and distributed applications is the. International standard organization"s open system interconnect (iso/osi) model. The internet protocol stack tcp/ip (transmission control protocol/internet protocol) model presents a group of protocols optimized for inter-computer communications and in particular for communications between multiple applications that may run on one computer. Tcp/ip model transmission control protocol / internet protocol. Last week we briefly explained the 2 models as shown below. Represents data to the user and controls dialogue. Supports communication between diverse devices across diverse networks. Controls the hardware devices and media that make up the network. Below, we explain some of the above protocols:
