[freenet-dev] RemoteNodeExpert

[Ian Clarke]

To illustrate the possibilities of the next generation routing algorithm 
I've implemented a class which gathers information about the performance 
of remote nodes, and uses that information to estimate the time required 
to retrieve some information from that note.

The most important part of this is the RoutingTimeEstimator class, 
however it will also take into consideration the likelihood that a 
contact attempt will fail, and further it will monitor the ratio of 
DataNotFound responses, watching out for anything unusual.

See the attached file.

Ian.

-- 
Ian Clarke                                                  ian at locut.us
Coordinator, The Freenet Project              http://freenetproject.org/
Founder, Locutus                                        http://locut.us/
Personal Homepage                                   http://locut.us/ian/
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package freenet.node.rt;

public class RemoteNodeExpert  {
   protected static int averageDataSize = 1000000;
   protected static int globalRetrievals = 0;
   protected static int globalFailures = 0;

   protected int contactsSucceeded = 0, contactsFailed = 0,
     contactFailureTime=0;
   protected int retrievals = 0, failures = 0;
   protected ResponseTimeEstimator rte;

   public RemoteNodeExpert(int accuracy)   {
      rte = new ResponseTimeEstimator(accuracy);
   }

   public RemoteNodeExpert(byte[] b)   {
      // TBD
     }

   public static void setAverageDataSize(int averageDataSize)   {
      RemoteNodeExpert.averageDataSize = averageDataSize;
   }

   public byte[] serialize()  {
      // TBD
   }


   public int estimateRoutingTime(Key key)   {
      // Return the estimated time for retrieval plus the potential
      // time wasted if the connection fails normalized by the liklihood
      // of it failing.
      return rte.guess(key) + (contactFailureTime / contactsSucceeded);
   }


   public void reportDataRetrieval(Key key,
                                   int timeToResponse,
                                   int timeForCompletion,
                                   int dataSize)  {
      retrievals++;
      globalRetrievals++;
      int normalizedTime = timeToResponse+
        (timeForCompletion * (averageDataSize / dataSize));
      rte.report(key, normalizedTime);
   }

   public void reportDataRetrievalFailure()  {
      failures++;
      globalFailures++;
     }

   public void reportContactSuccess()   {
      contactsSucceeded++;
     }

   public void reportContactFailure(int time)  {
        contactFailureTime+= time;
     }

   public float failureRatioRelativeToAverage()   {
      return (((float) retrievals) / ((float) failures)) -
        (((float) globalRetrievals) / ((float) globalFailures));
   }
}
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