routing
Class MaxPropRouterWithEstimation

java.lang.Object
  routing.MessageRouter
      routing.ActiveRouter
          routing.MaxPropRouterWithEstimation

public class MaxPropRouterWithEstimation
extends ActiveRouter

Implementation of MaxProp router as described in MaxProp: Routing for Vehicle-Based Disruption-Tolerant Networks by John Burgess et al. but with parameter estimation for finding an alpha based on timescale definition: Extension of the protocol by adding a parameter alpha (default 1) By new connection, the delivery likelihood is increased by alpha and divided by 1+alpha. Using the default results in the original algorithm. Refer to Karvo and Ott, Time Scales and Delay-Tolerant Routing Protocols Chants, 2008 This version tries to estimate a good value of alpha from a timescale parameter given by the user, and from the encounters the node sees during simulation.

Field Summary

static int	BYTES_TRANSFERRED_AVG_SAMPLES Over how many samples the "average number of bytes transferred per transfer opportunity" is taken
static double	DEFAULT_ALPHA The default value for alpha
static java.lang.String	MAXPROP_NS MaxPROP router's setting namespace ("MaxPropRouterWithEstimation")
static java.lang.String	TIME_SCALE_S

Fields inherited from class routing.ActiveRouter

DELETE_DELIVERED_S, deleteDelivered, RESPONSE_PREFIX, sendingConnections, TTL_CHECK_INTERVAL

Fields inherited from class routing.MessageRouter

B_SIZE_S, DENIED_NO_SPACE, DENIED_OLD, DENIED_TTL, DENIED_UNSPECIFIED, MSG_TTL_S, msgTtl, Q_MODE_FIFO, Q_MODE_RANDOM, RCV_OK, SEND_QUEUE_MODE_S, TRY_LATER_BUSY

Constructor Summary

protected	MaxPropRouterWithEstimation(MaxPropRouterWithEstimation r) Copy constructor.
	MaxPropRouterWithEstimation(Settings settings) Constructor.

Method Summary

int	calcThreshold() Calculates and returns the current threshold value for the buffer's split based on the average number of bytes transferred per transfer opportunity and the hop counts of the messages in the buffer.
void	changedConnection(Connection con) Called when a connection's state changes.
double	getCost(DTNHost from, DTNHost to) Returns the message delivery cost between two hosts from this host's point of view.
protected Message	getOldestMessage(boolean excludeMsgBeingSent) Returns the next message that should be dropped, according to MaxProp's message ordering scheme (see MaxPropTupleComparator).
RoutingInfo	getRoutingInfo() Returns routing information about this router.
Message	messageTransferred(java.lang.String id, DTNHost from) This method should be called (on the receiving host) after a message was successfully transferred.
MessageRouter	replicate() Creates a replicate of this router.
protected void	transferDone(Connection con) Method is called just before a transfer is finalized at ActiveRouter.update().
void	update() Checks out all sending connections to finalize the ready ones and abort those whose connection went down.
protected boolean	updateEstimators(DTNHost host) Updates the MaxPROP estimators
protected void	updateParam() update the alpha parameter based on the estimators

Methods inherited from class routing.ActiveRouter

addToSendingConnections, canStartTransfer, checkReceiving, createNewMessage, dropExpiredMessages, exchangeDeliverableMessages, getConnections, getMessagesForConnected, init, isSending, isTransferring, makeRoomForMessage, makeRoomForNewMessage, receiveMessage, requestDeliverableMessages, shuffleMessages, startTransfer, transferAborted, tryAllMessages, tryAllMessagesToAllConnections, tryMessagesForConnected, tryMessagesToConnections

Methods inherited from class routing.MessageRouter

addApplication, addToMessages, compareByQueueMode, deleteMessage, getApplications, getBufferSize, getFreeBufferSize, getHost, getMessage, getMessageCollection, getNrofMessages, hasMessage, isDeliveredMessage, isIncomingMessage, messageAborted, putToIncomingBuffer, removeFromIncomingBuffer, removeFromMessages, sendMessage, sortByQueueMode, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

BYTES_TRANSFERRED_AVG_SAMPLES

public static int BYTES_TRANSFERRED_AVG_SAMPLES

Over how many samples the "average number of bytes transferred per transfer opportunity" is taken

MAXPROP_NS

public static final java.lang.String MAXPROP_NS

MaxPROP router's setting namespace ("MaxPropRouterWithEstimation")

See Also:

Constant Field Values

TIME_SCALE_S

public static final java.lang.String TIME_SCALE_S

See Also:

Constant Field Values

DEFAULT_ALPHA

public static final double DEFAULT_ALPHA

The default value for alpha

See Also:

Constant Field Values

Constructor Detail

MaxPropRouterWithEstimation

public MaxPropRouterWithEstimation(Settings settings)

Constructor. Creates a new prototype router based on the settings in the given Settings object.

Parameters:

settings - The settings object

MaxPropRouterWithEstimation

protected MaxPropRouterWithEstimation(MaxPropRouterWithEstimation r)

Copy constructor. Creates a new router based on the given prototype.

Parameters:

r - The router prototype where setting values are copied from

Method Detail

changedConnection

public void changedConnection(Connection con)

Description copied from class: ActiveRouter

Called when a connection's state changes. This version doesn't do anything but subclasses may want to override this.

Overrides:

changedConnection in class ActiveRouter

Parameters:

con - The connection that changed

updateEstimators

protected boolean updateEstimators(DTNHost host)

Updates the MaxPROP estimators

Parameters:

host -

updateParam

protected void updateParam()

update the alpha parameter based on the estimators

messageTransferred

public Message messageTransferred(java.lang.String id,
                                  DTNHost from)

Description copied from class: MessageRouter

This method should be called (on the receiving host) after a message was successfully transferred. The transferred message is put to the message buffer unless this host is the final recipient of the message.

Overrides:

messageTransferred in class ActiveRouter

Parameters:

id - Id of the transferred message

from - Host the message was from (previous hop)

Returns:

The message that this host received

transferDone

protected void transferDone(Connection con)

Method is called just before a transfer is finalized at ActiveRouter.update(). MaxProp makes book keeping of the delivered messages so their IDs are stored.

Overrides:

transferDone in class ActiveRouter

Parameters:

con - The connection whose transfer was finalized

getOldestMessage

protected Message getOldestMessage(boolean excludeMsgBeingSent)

Returns the next message that should be dropped, according to MaxProp's message ordering scheme (see MaxPropTupleComparator).

Overrides:

getOldestMessage in class ActiveRouter

Parameters:

excludeMsgBeingSent - If true, excludes message(s) that are being sent from the next-to-be-dropped check (i.e., if next message to drop is being sent, the following message is returned)

Returns:

The oldest message or null if no message could be returned (no messages in buffer or all messages in buffer are being sent and exludeMsgBeingSent is true)

update

public void update()

Description copied from class: ActiveRouter

Checks out all sending connections to finalize the ready ones and abort those whose connection went down. Also drops messages whose TTL <= 0 (checking every one simulated minute).

Overrides:

update in class ActiveRouter

See Also:

ActiveRouter.addToSendingConnections(Connection)

getCost

public double getCost(DTNHost from,
                      DTNHost to)

Returns the message delivery cost between two hosts from this host's point of view. If there is no path between "from" and "to" host, Double.MAX_VALUE is returned. Paths are calculated only to hosts that this host has messages to.

Parameters:

from - The host where a message is coming from

to - The host where a message would be destined to

Returns:

The cost of the cheapest path to the destination or Double.MAX_VALUE if such a path doesn't exist

calcThreshold

public int calcThreshold()

Calculates and returns the current threshold value for the buffer's split based on the average number of bytes transferred per transfer opportunity and the hop counts of the messages in the buffer. Method is public only to make testing easier.

Returns:

current threshold value (hop count) for the buffer's split

getRoutingInfo

public RoutingInfo getRoutingInfo()

Description copied from class: MessageRouter

Returns routing information about this router.

Overrides:

getRoutingInfo in class MessageRouter

Returns:

The routing information.

replicate

public MessageRouter replicate()

Description copied from class: MessageRouter

Creates a replicate of this router. The replicate has the same settings as this router but empty buffers and routing tables.

Specified by:

replicate in class MessageRouter

Returns:

The replicate