A user opens three browsers on the same PC to access www.cisco.com to search for certification course information. The Cisco web server sends a datagram as a reply to the request from one of the web browsers. Which information is used by the TCP/IP protocol stack in the PC to identify which of the three web browsers should receive the reply?

A user opens three browsers on the same PC to access www.cisco.com to search for certification course information. The Cisco web server sends a datagram as a reply to the request from one of the web browsers. Which information is used by the TCP/IP protocol stack in the PC to identify which of the three web browsers should receive the reply?

  • the source IP address
  • the destination port number
  • the source port number
  • the destination IP address
    Answers Explanation & Hints:

    Each web browser client application opens a randomly generated port number in the range of the registered ports and uses this number as the source port number in the datagram that it sends to a server. The server then uses this port number as the destination port number in the reply datagram that it sends to the web browser. The PC that is running the web browser application receives the datagram and uses the destination port number that is contained in this datagram to identify the client application.