Network, Internet, Personal & Public Communications

Study  Guide

Basic Communication Model

Computer  communications  describes  a  process  in  which  two  or  more  computers  or  devices  transfer  data,  instructions,  and  information.

Sending  device

Communications  channel

Receiving  device

Each  one  of  these  areas  have  corresponding  IT  systems.

What is a Network?

In  order  to  establish  the  basic  communication  model  in  an  IT  system,  we  must  first  create  network.  !A   network   is   a   collection   of   computers   and   devices  connected   together   via   communications   devices   and  transmission  media.  

Facilitating  communications Sharing  hardware

Sharing  data  and  information

Sharing  softwareTransferring  funds

General  network  functions  -‐  

Uses of Computer Communications

Blogs

Chat  rooms E-‐mail

Newsgroups Internet

Instant  Messageing

FTP

RSS VoIP

Wikis

Web  Folders

Video  Conference

and  many  more…

Common Ways of Connecting

Ethernet  Cables  the  most  common  type  of  connection  computers  use  in  a  local   area   network   (LAN).   An   Ethernet   port   looks   much   like   a   regular  phone  jack,  but  it  is  slightly  wider.  This  port  can  be  used  to  connect  your  computer   to   another   computer,   a   local   network,   or   an   external   DSL   or  cable  modem.

Wifi  Short  for  "Wireless  Fidelity."  Wi-‐Fi  refers  to  wireless  networking   technology   that   allows   computers   and  other  devices  to  communicate  over  a  wireless  signal.

Common Ways of Connecting

RFID   Stands   for   "Radio-‐Frequency   Identification."  RFID   is  a  system  used  to  track  objects,  people,  or  animals   using   tags   that   respond   to   radio   waves.  RFID   tags  are  commonly  used   inside   retails   shops  to  stop  shoplifters.  

Bluetooth   This   wireless   technology   enables   communication   between  Bluetooth-‐compatible   devices.   It   is   used   for   short-‐range   connections  between   desktop   and   laptop   computers,   PDAs   (like   the   Palm   Pilot   or  Handspring   Visor),   digital   cameras,   scanners,   cellular   phones,   and  printers.

Common Ways of Connecting2G  is  short  for  second-‐generation  wireless  telephone  technology.  Second  generation  2G  cellular  telecom  networks  were  commercially  launched  on  the   GSM   standard   in   Finland.   Through   a   2G   network,   voice   and   data  transfers  were  now  possible  in  the  form  of  SMS  and  MMS.

3G   short   for   third   Generation,   is   the   third   generation   of   mobile  telecommunications   technology.   Increased   data   reception   allows   for  application   in   wireless   voice   telephony,   mobile   Internet   access,   fixed  wireless  Internet  access,  video  calls  and  mobile  TV.

4G   is   the   fourth   generation   of   mobile   phone   mobile   communication  technology   standards.   Provides  mobile   ultra-‐broadband   Internet   access,  for  example  to  laptops  with  USB  wireless  modems,  to  smartphones,  and  to   other   mobile   devices.   Conceivable   applications   include   amended  mobile  web  access,  IP  telephony,  gaming  services,  high-‐definition  mobile  TV,  video  conferencing,  3D  television,  and  cloud  computing.

Global Positioning System (GPS)A   space-‐based   satellite   navigation   system   that  provides   location   and   time   information   in   all  weather  conditions,  anywhere  on  or  near   the  Earth  where  there   is  an  unobstructed   line  of  sight  to  four  or   more   GPS   satellites.   Commonly   used   for   map  applications   and   location   services   tracking   that   is  used  by  many  common  mobile  apps  such  as  Google  Maps,  Viber,  Facebook,  etc.

Although  many   people   see   this   technology   as   an  invasion   of   their   privacy,   it   is   useful   for   apps   to  track   your   location   in   order   to   provide   better  products   and   services   for   their   customers.  Example:   If   you   wanted   to   know   where   the  nearest  Starbucks  is  from  your  current  location.

Local Area Networks (LAN)A   computer   network   that   spans   a  relatively   small   area.   Most   LANs   are  confined   to   a   single   building   or   group  of  buildings,   however,   one   LAN   can   be  connected   to   other   LANs   over   any  distance   via   telephone   lines   and   radio  waves.   A   system   of   LANs   connected   in  this   way   is   called   a   wide-‐area   network  (WAN).  !LAN   that   connect   using    Wifi   signals   are  called  WLAN  (Wireless  LAN)

Network TopologyTopology   refers   to   the   shape  of  a  network,  or   the  network's   layout  and  determines   the   way   that   the   devices   on   a   network   are   arranged   to  communicate  with  each  other.  

Network ArchitectureThe  design  of  computers,  devices,  and  media  on  a  network  is  sometimes  called  the  network  architecture.  There  are  two  common  types. Peer-‐to-‐Peer  (P2P)  

P2P  describes  a  network  on  which  users  access  each  other’s  hard  disks  and  

exchange  files  directly  over  the  Internet.

Client  /  Server  Transmission  of  data  is  managed  by  a  server  or  main  

computer  that  helps  transfer  data  and  information  to  the  rest  of  the  network.

Intranet vs. Extranet

"Intra"  means  "internal"  or  "within,"  so  an  Intranet  is  an   internal   or   private   network   that   can   only   be  accessed   within   the   confines   of   a   company,  university,   or   organization.   "Inter"  means   "between  or   among,"   hence   the   difference   between   the  Internet  and  an  Intranet.

INTRANET

EXTRANETAn  extranet  actually  combines  both  the  Internet  and  an  intranet.   It   extends   an   intranet,   or   internal   network,   to  other   users   over   the   Internet.   Most   extranets   can   be  accessed  via  a  Web  interface  using  a  Web  browser.  Since  secure   or   confidential   information   is   often   accessible  within   an   intranet,   extranets   typically   require  authentication  for  users  to  access  them.

Intranet vs. Extranet

EXTRANET INTRANET

Cable vs. DSL

A  cable  modem  is  used  for  connecting  to  the  Internet   and   is   much   faster   than   a   typical  dial-‐up   modem.   While   a   56K   modem   can  receive  data  at  about  53  Kbps,  cable  modems  support  data  transfer  rates  of  up  to  30  Mbps.  That's   over   500   times   faster.   However,  most  ISPs   limit   their   subscribers'   transfer   rates   to  less  than  6  Mbps  to  conserve  bandwidth.

CABLE

DSLStands   for   "Digital   Subscriber   Line."   It   is  medium   for   transferring   data   over   regular  phone  lines  and  can  be  used  to  connect  to  the  Internet.  However,  like  a  cable  modem,  a  DSL   circuit   is  much   faster   than  a   regular  phone   connection,   even   though   the  wires  it  uses  are  copper  like  a  typical  phone  line.

ADVANTAGE    You  can  access  both  the  internet  and  your  phone  line  at  the  same  time  Faster  speed  than  dial-‐up  Ability   to   choose   between   different   connection   speeds   and   pricing   from  various  providers  DISADVANTAGE    Receives  data  faster  than  it  sends  it  Sometimes  not  available  in  remote  areas  The   farther   you   are   from   the   provider’s   central   location,   the   slower   the  transmission

ADVANTAGE    Performance  isn’t  based  on  distance  from  the  provider’s  central  location  Faster  speed  than  dial-‐up  and  most  often  DSL  DISADVANTAGE    You   share   the   available   bandwidth   of   a   single   cable   line  with   others   in   your  neighborhood.   The   more   people   using   it   at   the   same   time,   the   slower   the  performance.  Could  be  more  costly  than  DSL  Sometimes  not  available  in  remote  areas

What is Bandwidth?

Bandwidth   describes   the   maximum   data   transfer  rate   of   a   network   or   Internet   connection.   It  measures  how  much  data  can  be  sent  over  a  specific  connection   in   a   given   amount   of   time.   Commonly  measured   in   kilo   bits   per   second   (kbps)   -‐   Example:  3Mbps

Bandwidth   is   normally   divided   for   upload   and  download  of  data  and  information.  !The   higher   the   bps   the   faster   the   connection.  However   this   will   still   depend   on   the   sending   and  receiving  device.  

Russia:  5.074  Mb/s  China:  1.769  Mb/s  Japan:  10.795  Mb/s  India:  1.238  Mb/s  Thailand:  3.257  Mb/s  Vietnam:  1.471  Mb/s  Malaysia:  2.299  Mb/s  Indonesia:  1.437  Mb/s  Taiwan:  3.944  Mb/s  Cambodia:  1.476  Mb/s

Average  Internet  Speeds  in  Asia