Chapter 6 In Class Notes Flashcards
A collection of computers that communicate with one
another over transmission lines or wirelessly
Computer Network
What are the 3 types of computer networks
1 Local area Network (LAN)
- Wide are network (WAN)
- The internet and internets
Network where computers are connected between two or more separated sites
WAN
Network where Computers are connected at a single physical site
LAN
Networks of networks
internet and internets
is used to facilitate effective
communication between the myriad devices
operating in the communication system that is a
computer network
A “layered protocol”
What Are the Components of a
LAN?
You have one central location with a Switch, an Access Point, and Other components. The computers all connect to the central location and also printers can connect.
• Connects a device’s circuitry to the network’s wires
• Works with programs in each device to implement
protocols for communication
Network Interface Card (NIC or WNIC)
LAN Protocol (Device to Device Comm.) 2 types
• IEEE 802.3 (a.k.a ethernet) – Wired LAN – 10/100/1000 Mbps – Switches detect the speed that a given device can handle and communicates at the same speed • IEEE 802.11 – Wireless LAN – 802.11n (allows speeds up to 600 Mbps) – Bluetooth
Topology of LAN
local area network and local area network with wireless
Transmission line of local area network
UTP or optical fiber and UTP or opitcal for non-wireless connectors
Transmission speed of LAN
10/100/1000 Mbps. Possible 1 Gbps. Up to 600 Mbps for wireless
Functions of the LAN Device? Give 5
• Switch processing: IEEE 802.3 wired LAN traffic
• Access-point processing: IEEE 802.11 wireless LAN
traffic
• Translating between IEEE 802.3 and IEEE 802.11
• Converting between Analog and Digital
• Assigning private IP addresses
• Converting IP address between private and public IP
addresses
• Routing packets
• And more … 10 Copyright © 2013 Pearson Education, Inc. P
When you connect your SOHO, tablet, or mobile
device to the internet, you are connecting to a
WAN
via an internet service provider or ISP
An ISP has three important functions
– Providing you with a legitimate internet address
• Whatismyipaddress.com
– Serving as your gateway to the internet
– Paying for the internet (paying fees, and other charges
on your behalf).
Process of connecting to an ISP. 4 of them
- Personal computer or LAN connnects to Modem.
- From Modem it goes to Switch at telephone or cable company.
- From Telephone or Cable company it goes to the Internet Service Provider.
- From internet service provider you go to Internet.
Connecting to an ISP
• SOHO LANs and individual devices connect to an
ISP in one of the following three ways:
– A digital subscriber line (DSL)
– Cable TV line
– WAN wireless connection (e.g. mobile networks)
converts the
digital data in your computer into an analog signal
that can be transmitted via your ISP to another device
somewhere on the Internet
A modem or modulator/demodulator
converts the
digital data in your computer into an analog signal
that can be transmitted via your ISP to another device
somewhere on the Internet.
A modem, or modulator/demodulator
DSL Modems use the same lines as
voice telephones
DSL signals do not interfere with
telephone service
and occur simultaneously
The protocols used on the internet are arranged
according to a
predefined structure
There are five protocol types arranged in layers
Top layer includes protocols for applications like
browsers and web servers
– Next two layers are protocols for data communications
– Bottom two layers are protocols for intra network data
communication
What are the names of each layer starting from top.
Application Transport Internet Data Link Physical
Hyper Text Transport Protocol (http)
Protocol between browsers and Web servers
request/response
HTTPS -
secure HTTP data transmission
Simple Mail Transfer Protocol (SMTP) does what
Email transmissions (see settings on mobile)
File Transfer Protocol (ftp) does what
– Used to move files over the internet
– Secure version is SFTP
Internet vs. Web
• The “Internet” involves any of the four application
layer protocols we have discussed
• The Web involves only the HTTP or HTTPS protocol
25 Copyright © 2013 Pearson Education, Inc. Publishing As Prentice Hall
– Breaks traffic up into packets and sends each one along
its way
– Works with TCP programs to ensure information arrives
– TCP programs detect missing data and request retransmission
as needed
• TCP or Transmission Control Protocol
– Specifies the routing of information through the network
(IP address)
– Goal is make sure that all of the puzzle pieces (packets)
can be re-assembled at their destination
IP (Internet Protocol)
“A special purpose computer that moves packet traffic
according to the rules of IP protocol”.
ROUTER
Public IP Addresses. 3 things about it
– Identify a particular device on public Internet
– Public IP addresses must be unique, worldwide
– Assignment controlled by ICANN (Internet Corporation
for Assigned Names and Numbers)
– Identify a particular device on a private network
Private IP Addresses
IP Addressing major benefits
– Public IP: All devices on LAN share a public IP address.
– Private IP address, need not register computer with
ICANN-approved agencies.
– Four decimal dotted notation like 165.193.123.253
IPv4
Newer format (global pressures)
IPv6
Worldwide-unique name affiliated with a public IP
address
Domain name
Virtual Private Networks (VPN). 3 things about it
• Using the internet to create the appearance of private pointto-
point connections
• VPN client software encrypts messages and appends the IP
address of the VPN Server to the package.
• VPN Server receives the package, strips of IP address,
decodes the message, and delivers to recipient on LAN
What Processing Occurs on a
Typical Web Server?
3 tier architecture
What 3 things are included in the Three-Tier Architecture
- User Tier
- Server tier
- database tier
• Computers, phones, tablets (all device
User tier
• Computers that run a DBMS that processes requests to
retrieve and store data
database tier
• Computers that run Web servers and process application
programs
server tier
What Processing Occurs on a
Typical Web Server?
First you have user, which is the user tier, using web browsers. Then you have the web server tier that applications and instructions. The server tier and the Database tier interact and pass back and forth instructions and data.
Common language for defining the structure and
layout of web pages
HTML
is used for more
intricate styling of page elements
CSS or a cascading style sheet
– Fixes several HTML deficiencies
– Program-to-program interaction over Web
• XML (eXtensible Markup Language)
– Browser add-on for animation, movies, and other
advanced graphics inside a browser (farewell speech?)
Flash
– Browser add-on with greater functionality than Flash
Silverlight
– Supports animation, movies, and graphics
HTML 5
– Elastic leasing of pooled computer resources over the
Internet
Cloud
– Dynamically increasing/decreasing a leased resource
programmatically in a short span of time, and only pay for
resources used
Elastic
Many organizations using the same physical hardware via virtualization (see Virtualbox)
Pooled
Q5. Why Is the Cloud the Future for Most
Organizations?
• Cloud
– Elastic leasing of pooled computer resources over the
Internet
• Elastic
– Dynamically increasing/decreasing a leased resource
programmatically in a short span of time, and only pay for
resources used
• Pooled
– Many organizations using the same physical hardware
via virtualization (see Virtualbox)
When Does the Cloud Not Make Sense?`
• Only when law or industry standard practices require
physical control over the data
– Healthcare and banking are good examples
• Private cloud
• In-house hosting, delivered via Web service
standards`
How Can Organizations Use the
Cloud? 3 ways
SaaS (software as a service)
PaaS (platform as a service)
laaS (infrastructure as a service)
Examples of SaaS
Salesforce.com
iCloud
Office 365
Examples of Paas
Microsoft Azure
Oracle on Demand
Examples of laaS
Amazon Elastic Cloud 2
Amazon Simple Stoarge Service
Q7: 2022?
- Cloud computing benefit
- Individuals on iCloud
- Small groups using Office 365
- Startups Using PaaS
- Huge organizations using IaaS
- New categories of products and services
- Create new jobs?
- Tele-action
- Telediagnosis, telesurgery, telelaw enforcement
