What is CDN(Content delivery network) / Virtual Ghost

Servers storing static content(Homepage, Videos, image, Java script files etc) near to client. This is a Overlay Network
CDNs can store dynamic contents(but this is still under progress).

CDN serving web page to Browser

CDN 

// HTTP REQUEST
HTTP GET google.com
header {
  /*Mandatory added by HTTP End*/
  Cookie: "kanskndakn",
  Host:
  UserAgent: Browser,
  Accept: */*       
  Accept-Encoding: gzip, deflate, br
  Connection: Keepalive
}
        

// HTTP RESPONSE
200 OK
cookie {value="ansjakjdbkja", expires="6 months"}
header {
  /*Mandatory added by HTTP End*/
  expires: -1,
  Cache-Control: private,
  Content-type: text/html,
  Content-encoding: gzip,
  Server: gws,
  Content-length: 8311
}
body {  // google Home Page
     This might be Image from CDN 
     url = "cdn-url/home.png"
}