Data Networking/Fall 2014/Priya/Design Algorithm

How the network reacts from the point where a client joins our network, to the point where the client is served with the requested html page is described in the following steps.

( I ) Client attempting to join our network, named NEU-NETWORKS

    Validate the client's login credentials.
    
    If valid client
         Client successfully connects to NEU-NETWORKS
    else
         Contact the Network Administrator to provide the valid settings for connecting to our network. 
         The client status now changes to valid

( II ) The client needs an IP address that's only provided by our network DHCP server, hence the client should follow the following steps to acquire a valid IP address

    Check wlan interface if configured as Static or Automatic (DHCP).
    
    If Static
         Change the wlan interface configuration settings to Automatic(DHCP)
    
    else (DHCP discover)
         Contact DHCP server to fetch the IP address, Gateway IP address, DHCP server details, Primary and 
         Secondary DNS server details.
    
    If the DHCP server fails to reply to the client
         Contact DHCP Server administrator to verify the status the DHCP server status
         DHCP server settings verified, up and running
         Repeat the IP address acquisition (DHCP discover) procedure

( III ) After receiving the DHCP server settings, the client can attempt to connect to NEU NETWORKS website www.neunetworks.com via a web browser

    Client sends a DNS query to Primary DNS server for resolving the hostname www.neunetworks.com to an IP address
    
    If Primary DNS server is reachable
         Primary DNS server fetches the RR records
         Provides the list of web servers (Primary & Backup) hosting www.neunetworks.com in DNS response message
    
    else 
         Report Primary DNS server failure to Network Administrator
         If Secondary DNS server is reachable
              Primary DNS server fetches the RR records
              Provides the list of web servers hosting www.neunetworks.com in DNS response message
         else
              Report Secondary DNS server failure to Network Administrator

( IV ) In case the DNS server was able to successfully provide the list of web servers hosting www.neunetworks.com, the client's browser can perform the following tasks

    Request web page (html file) from web server using the provided web server's IP address
    
    If web server (Primary or Backup) is reachable
         Web Server responds with the requested html file for www.neunetworks.com
    else 
         Report Web server failure to Network Administrator

The complete flow chart is illustrated below in the second part of this section, "Flow Chart". Click here to view the flow chart