public interface IRouter {

	//pre - p is a valid packet
	//post - p has been added to the input queue
	//			p has been added to the service level queue if appropriate
	public void addPacket(Packet p);

	//pre - packetID may or may not be a valid packetID
	//post - if packetID was the ID of a packet on the input queue
	//			that packet has been removed from the input queue, and
	//			from any service queues it belonged to
	//			Returns the packet or null
	public Packet removePacket(int packetID);

	//pre - none
	//post - if the input queue is empty, do nothing
	//			if the input queue is not empty, process a packet
	//			from the input queue.  The selection of the packet
	//			to process should be done according to the writeup.
	public void processPacket();

	//pre - option is a number betwee 1 and 4
	//post - print the contents of the specified queue
	//		1 - input queue
	//		2 - service level high queue
	//		3 - output queue for port 0
	//		4 - output queue for port 1
	//	RIW - the return value of print will always be true
	//	since the preconditions ensure option is valid  3/22/12
	public boolean print(int option);

}