protected void toLayer3(int callingEntity, Packet p)
    {
        nToLayer3++;

        int destination;
        double arrivalTime;
        Packet packet = new Packet(p);

        if (traceLevel > 2)
        {
            System.out.println("toLayer3: " + packet);
        }

        // Set our destination
        if (callingEntity == A)
        {
            destination = B;
        }
        else if (callingEntity == B)
        {
            destination = A;
        }
        else
        {
            System.out.println("toLayer3: Warning: invalid packet sender");
            return;
        }

        // Simulate losses
        if (rand.nextDouble() < lossProb)
        {
            nLost++;

            if (traceLevel > 0)
            {
                System.out.println("toLayer3: packet being lost");
            }

            return;
        }

        // Simulate corruption
        if (rand.nextDouble() < corruptProb)
        {
            nCorrupt++;

            if (traceLevel > 0)
            {
                System.out.println("toLayer3: packet being corrupted");
            }

            double x = rand.nextDouble();
            if (x < 0.75)
            {
                String payload = packet.getPayload();

                payload = "?" + payload.substring(payload.length() - 1);

                packet.setPayload(payload);
            }
            else if (x < 0.875)
            {
                packet.setSeqnum(Math.abs(rand.nextInt()));
            }
            else
            {
                packet.setAcknum(Math.abs(rand.nextInt()));
            }
        }

        // Decide when the packet will arrive.  Since the medium cannot
        // reorder, the packet will arrive 1 to 10 time units after the
        // last packet sent by this sender
        arrivalTime = eventList.getLastPacketTime(destination);

        if (arrivalTime <= 0.0)
        {
            arrivalTime = time;
        }

        arrivalTime = arrivalTime + 1.0 + (rand.nextDouble() * 9.0);

        // Finally, create and schedule this event
        if (traceLevel > 2)
        {
            System.out.println("toLayer3: scheduling arrival on other side");
        }
        Event arrival = new Event(arrivalTime, FROMLAYER3, destination, packet);
        eventList.add(arrival);
    }