can any body explain me what this code do exactly

//you could use either ip or hostname
var ip = "127.0.0.0";
var hostname = "hostname.com";

  Ping pinger = new Ping ();

            byte[] buffer = Encoding.ASCII.GetBytes ("test123");
            int timeout = 60;
            PingReply reply = pinger.Send (ip, timeout, buffer);
            if (reply.Status == IPStatus.Success)
            {
//hooray
            }else{
//nope
}

try{
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
request.Method = "HEAD";
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
WebHeaderCollection headers = response.Headers;
//hooray

}catch(Exception ex){
//nope
}

WebClient client = new WebClient ();
string reply = client.DownloadString ("www.google.com");