BIT 3554 Exam 1
Protocol
the language used by applications to communicate with one another · Each application needs to develop its own ________________ to be able to communicate on the network
Early Resource Sharing
- 1960s - Department of Defense for Advanced Research Projects Agency (ARPA) became interested in finding ways to share resources o Need to interconnect all computers o Allow a researcher to use the best suitable computer to perform a given task o Everything was all on one network - They are pushing for a more distributed network so that if one piece is attacked, the rest can still work. Diversify and get all eggs out of one basket. o ARPANET § ARPANET was the prototype of the internet
Overview of global internet use
- 4.66 billion people on internet - 59.5% of global population - This means about 3 billion people do not have internet connection yet - Many organizations in the government are helping to reach those who do not have internet
user interface; shared
- Each application offers a specific service with its own form of _________________, but all applications can communicate over a single, __________ network
digital; analog
- Network only carries ________________ and _____________ signals - Two broad categories of physical media are ____________ and __________
• Advantages of resource sharing
- Resource availability - Concurrency - Possible cost reduction - Possible security enhancements
ping
- Sometimes site may reject ______________ packets to avoid Denial of Service (DOS) attacks • Heavily used as a diagnostic tool
Network Interface Layer / Data Link (Layer 2)
- Specifications about ▪ network addresses - MAC address ▪ maximum packet size that a network can support ▪ protocols used to access the underlying medium ▪ and hardware addressing
Telecommunications
- _____________________ is really people using devices to communicate across long distances
Circuit switch
- _______________________ - a line is dedicated to just A and B: This is not efficient for the new network because of the amount of users
Department of Defense for Advanced Research Projects Agency (ARPA)
1960s - ___________________________________________________________________ became interested in finding ways to share resources ➢Need to interconnect all computers ➢Allow a researcher to use the best suitable computer to perform a given task
OSI vs TCP/IP Model
7 layers vs 5 layers: Presentation, Session, & Application combine to form just the 5th layer which is called Application in IP Model
public; subscribers
A ___________ network provides services to ___________________
service provider
A company that offers network service is known as a ________________________
Possible security enhancements
Advantages of resource sharing - easier to secure a machine to make it more manageable
Resource Availability
Advantages of resource sharing - more people can access information, 24/7 - now if we want to check books online, it is more available and accessible than a physical library
Concurrency
Advantages of resource sharing - multiple people can use information at the same time, or can perform as task at the same time
exchange; procedures
Application Layer (Layer 5) ➢ specifies details about ▪ the format and the meaning of messages that applications can _______________ ▪ the ____________ to be followed
all function over the same network
As an application designer you don't have to worry about creating a network or understand how the network works because they ____________________________________________
Timeline of the Internet
Check Slides or notes o Introduction of FTP and TCP/IP changed the way we were able - gives flexibility and ability to handle data - provides the base for internet o Facebook was not the first social media - MySpace and others came before it § Facebook was requiring people to verify their identity o Web 2.0 - people can post their own content, user generate a lot of content on the internet o Web 3.0 - users will be involved even more in the virtual world
physical media
Data communication Involves the transmission of information over ____________________
o Network has made telecommuting available to individuals o It has changed business communication o An entire industry emerged that develops networking technologies, products, and services
Dramatic economic shifts from computer networking
protocols
Each layer has _____________ that are particular to that layer and only interacts with items in that layer
Ping and Traceroute
Example of simple network tools
Dramatic economic shifts
Growth of computer networking has led to ____________________
Analog and Digital Signals
How do we represent info/data?
§ Internet is made up of a large amount of independently operated networks
How does the internet work?
Protocol Suites and Layering Models
Instead of creating a protocol to cover all aspects simultaneously, YOU DIVIDE THE DATA INTO _____________________________ THAT FOCUS ON INDIVIDUAL ASPECTS OF THE ENTIRE PIECE OF DATA
public/private
Internet is based on _________________ ownership on networks
the hardware/software technologies
It is possible to design network applications, without understanding ________________________________
resource sharing
Main motivation of early networks was ______________________________
packet
Network Interface Layer / Data Link (Layer 2) - Specifications about --> maximum ____________ size that a network can support
addresses - MAC address
Network Interface Layer / Data Link (Layer 2) - Specifications about --> network _______________________
medium
Network Interface Layer / Data Link (Layer 2) - Specifications about --> protocols used to access the underlying _____________
services; application software(s)
Network _______________ are provided by __________________________
Ethernet
Network interface type
dedicated circuit
Old Time - Telephone systems use a physical pair of wires between two parties to form a ________________ --> Then came packet switching - is called point-to-point connection
share
Packet Switching - Allows multiple users to ___________ a network
reach; destination
Packet Switching - Devices throughout the network each have information about how to _________ each possible _______________
packets
Packet Switching - Divides data into small blocks, called ____________
big piece; PACKETS
Packet Switching - Instead of sending data in one ____________, the data is sent in _____________ that are smaller pieces of the entire piece of data
dynamic; already established connection
Packet switching is __________ while circuit switching uses an _________________________
Two technological changes fueled a shift away from resource sharing to new applications:
Resource Sharing ➔Communication ➢Higher communication speeds enabled applications to transfer large volumes of data quickly ➢The advent of powerful, affordable, personal computers provided the computational power needed for complex computation and graphical displays
➢Communication speeds ➢New applications
Resource Sharing ➔Communication The Internet changed in two significant ways:
network-independent packet
TCP/IP defines a ________________________________
1. Network Applications and network programming 2. Data communications 3. Packet switching and networking technologies 4. Internetworking with TCP/IP 5. Additional Networking concepts and technologies
The Five Key Aspects of Networking
heterogeneity
The success of TCP/IP lies in its tolerance of _______________________
packet switching
The whole internet is based on a ______________________ technology
- A unified
There is a ____________ underlying network that supports all applications
Transport Layer (Layer 4)
This is where we talk more about TCP, this protocol helps us address many different issues we can encounter during transmission
application
Transport Layer (Layer 4) - Provides for communication from an ____________________ program on one computer to an ________________ program on another
maximum rate; congestion; correct order
Transport Layer (Layer 4) ➢Includes specifications on ▪ controlling the ________________ a receiver can accept data ▪ mechanisms to avoid network ______________ ▪ techniques to insure that all data is received in the _____________________
§ Thailand has the highest internet speed § US places 9th overall in internet speed
Want faster internet?
it would have to be too complex
We cannot have one protocol to handle all of the aspects - __________________________________________
centralized; distributed
What might be the most important motivation of creating networks? - Sharing ___________________facilities ➔Fully ________________ information systems · Connecting devices together in one location
§ Resource sharing § Searching - when you google something you are trying to get information from the network
What might be the most important of creating networks?
The Internet
What's the most revolutionary invention in the 70s-80s?
5 Layers examples
o 5 layers § Layer 1: Physical (Hardware) § Layer 2: Network Interface (Ethernet) § Layer 3: Internet (IP) § Layer 4: Transport (TCP) § Layer 5: Application (HTTP)
Application layer
Where all network protocols happen, messaging, email, all applications that we use focus on this layer, top layer closest to the user, FTP
§ Nobody controls it is distributed
Who controls the internet?
Public
__________ refers to the general availability of service, not to the data being transferred
Low-Level; physical communication medium
______________ mechanisms and technologies used to send information across a __________________________: o A wire, radio wave, or light beam
Hard Disk
_________________ evolved over time to get smaller and smaller
Networking is
__________________ is used in every aspect of business
Networking
_____________________ has changed business communication
Application
______________________ a software that provides services to a user
Networking applications
_________________________ applications depend on communication between devices
Ping; Traceroute
a) __________ - sends message that is echoed by a remote computer b) _____________ - reports path to remote computer
Does everyone in the US have internet connection?
o 90% of the population in North America have and utilize internet access o Areas that have lower internet coverage have great internet growth
private
o A _______________ network is controlled by one particular group - could be a military network
Communication protocol or network protocol
o All entities in a network must agree on how information will be represented and communicated o All communicating parties follow the same set of rules called the _______________________ or ____________________
- Network applications may include:
o Email o File transfer o Web browsing o Voice telephone calls (VoIP) o Gmail o Text messaging o Google o Social Media
Measuring internet growth
o Estimates have been based on § Analyses by automated tools which probe computer addresses stored in large online databases (DNS) § Example of simple network tools Use both Ping and Traceroute in the command prompt
The difference between network and normal application:
o Google Docs vs. Microsoft Word o Network applications require network services
TCP/IP Internet Protocol Suite (TCP/IP)
o In 1973, Vinton Cerf and Robert Kahn suggested § Stop trying to find a single best solution § _____________________________________________________
Internet facts
o In the 1970s Bob Kahn and Vint Cerf co-created the internet o Paul Baran was trying to figure out a network that would survive a nuclear attack
Internet Trends
o New technologies and new applications continue to emerge o Analog --> Digital o One of the most interesting aspects of the internet: no matter how applications chance, the underlying technology essentially remains the same
underlying technology
o One of the most interesting aspects of the internet: no matter how applications chance, the ____________________ essentially remains the same
giant
o Original computer machines were _____________ geared for big corporations and companies - really big, expensive, and heavy § This is why there was such motivation to share a network to centralize data for these ____________ machines
Packet switching benefit
o These packets go through a shared connection in the middle, they can all send items through the network connection at the same time now because of packet switching - much more efficient of using network resources
Physical layer
o _____________________ - Cables, how do we use them, only helps define the physical aspect of the network
IBM Model 350:
o ________________________ had the potential to hold to hold 3.75 Mb - this was a giant hard disk that had very little potential to hold data § Typically, the whole system would be leased from IBM for 3,200$ a month - equivalent to 30,000$/month in today's money § The _____________ hard disk alone was 750$/month
What is data communications?
o • Involves the transmission of information over physical media o • The subject draws on ideas about electric current, light, and other forms of electromagnetic radiation o • Uses mathematics and includes various forms of analysis to design and build transmission systems - Focuses on the PHYSICAL LAYER
Digital Signals
restrict use to a fixed set of values
Packet switching
revolutionized data communications
Ping
sends message that is echoed by a remote computer - sends a few testing packets to a destination you want to ping with, that machine then responds and you will receive those packets back - by doing this you can test the route, and know how fast data transmission is on this route.
Analog Signals
use all values in a continuous range
expensive
why we needed a centralized network to connect people and businesses - This technology was ________________________ to buy, rent, transport
Growth of the internet
§ The internet has grown from an early research prototype connecting a handful of sites to a global communication system § 4.66 billion internet users as of 2020 (59.5% of the world population)
ARPANET (Advanced Research Projects Agency Network)
§ ______________________ was the prototype of the internet - 1968
ISO and the OSI Seven Layer Model
• International Standardization Organization (ISO) • International Telecommunications Union (ITU)
Some examples of network applications in layer 5
▪ email exchange ▪ file transfer ▪ web browsing ▪ telephone services ▪ and video teleconferencing
Network Interface Layer / Data Link (Layer 2)
➢ Specify details about communication between higher layers of protocols (implemented in SW) and the underlying network (implemented in hardware)
radio frequencies (physical layer)
➢ Specify details about the underlying transmission medium and hardware ➢ All specifications related to electrical properties, ______________________, and signals belong in layer 1
Application Layer (Layer 5)
➢ specifies how a pair of applications interact when they communicate ➢ specifies details about ▪ the format and the meaning of messages that applications can exchange ▪ the procedures to be followed ➢ Some examples of network applications in layer 5 ▪ email exchange ▪ file transfer ▪ web browsing ▪ telephone services ▪ and video teleconferencing
Packet switching changed networking in a fundamental way:
➢Allows multiple users to share a network ➢Divides data into small blocks, called packets ➢Devices throughout the network each have information about how to reach each possible destination
Internet Layer (Layer 3)
➢Layer 3 protocols specify communication across the Internet - This is where IP is defined at, Internet Protocol (IP)
Ping summary
➢Number of packets sent and received ➢Packet loss ➢Min/mean/max round trip times
• Transport Layer (Layer 4)
➢Provides for communication from an application program on one computer to an application program on another ➢Includes specifications on ▪ controlling the maximum rate a receiver can accept data ▪ mechanisms to avoid network congestion ▪ techniques to insure that all data is received in the correct order
