gridsim.net
Class Link

Object
  Thread
      Sim_entity
          Link

All Implemented Interfaces:

Cloneable, Runnable

Direct Known Subclasses:

FlowLink, SimpleLink

public abstract class Link
extends Sim_entity

This class provides a template for a Link which can connect two entities like routers, GridResources or any other new component that needs to use the network facilities in Gridsim.

In the network model used here, the links only introduce propogation delays. Routers are resposible for queueing and transmission delays. Also, links do not check whether the packets being sent through are of size smaller than the MTU. It is the responsibility of the upstream sender to check the size of the packet. The baud rate and the MTU attributes are stored in the links to facilitate routers and other entities that send data through a link.

Since:

GridSim Toolkit 3.1

Author:

Gokul Poduval & Chen-Khong Tham, National University of Singapore

Invariant:

$none

Nested Class Summary

Nested classes/interfaces inherited from class Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

protected double	baudRate_ Baud rate of this link in bits/s
static int	DEFAULT_BAUD_RATE Default baud rate of a link in bits/sec
static int	DEFAULT_MTU Default Maximum Transmission Unit (MTU) of a link in bytes
static int	DEFAULT_PROP_DELAY Default propagation delay of a link in millisecond
protected double	delay_ Propagation delay of this link in millisecond
protected int	MILLI_SEC A constant represents 1 second in milliseconds
protected int	MTU_ Maximum Transmission Unit (MTU) of this link in bytes

Fields inherited from class Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Link(String name, double baudRate, double propDelay, int MTU)
Constructs a Link which simulates a physical link between two entities.

Method Summary

abstract void	attach(Sim_entity end1, Sim_entity end2) Connects two entities using this link.
abstract void	attach(String end1, String end2) Connects two entities using this link.
double	getBaudRate() Returns the baud rate of the link in bits/s.
double	getDelay() Returns the tramssion delay that this link introduces.
int	getMTU() Returns the Maximum Transmission Unit of this Link

Methods inherited from class Sim_entity

add_generator, add_param, add_port, body, clone, get_id, get_name, get_port, get_port, get_stat, run, send_on, set_invisible, set_stat, sim_cancel, sim_completed, sim_current, sim_get_next, sim_get_next, sim_hold_for, sim_hold, sim_pause_for, sim_pause_for, sim_pause_until, sim_pause_until, sim_pause, sim_process_for, sim_process_for, sim_process_until, sim_process_until, sim_process, sim_putback, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_schedule, sim_select, sim_trace, sim_wait_for, sim_wait_for, sim_wait_for, sim_wait, sim_waiting, sim_waiting

Methods inherited from class Thread

activeCount, checkAccess, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class Object

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

Field Detail

delay_

protected double delay_

Propagation delay of this link in millisecond

baudRate_

protected double baudRate_

Baud rate of this link in bits/s

MTU_

protected int MTU_

Maximum Transmission Unit (MTU) of this link in bytes

DEFAULT_BAUD_RATE

public static final int DEFAULT_BAUD_RATE

Default baud rate of a link in bits/sec

See Also:

Constant Field Values

DEFAULT_PROP_DELAY

public static final int DEFAULT_PROP_DELAY

Default propagation delay of a link in millisecond

See Also:

Constant Field Values

DEFAULT_MTU

public static final int DEFAULT_MTU

Default Maximum Transmission Unit (MTU) of a link in bytes

See Also:

Constant Field Values

MILLI_SEC

protected final int MILLI_SEC

A constant represents 1 second in milliseconds

See Also:

Constant Field Values

Constructor Detail

Link

public Link(String name,
            double baudRate,
            double propDelay,
            int MTU)
     throws ParameterException,
            NullPointerException

Constructs a Link which simulates a physical link between two entities.

Parameters:

name - Name of this Link

baudRate - baud rate of this link (bits/s)

propDelay - Propogation delay of the Link in milli seconds

MTU - Maximum Transmission Unit of the Link in bytes. Packets which are larger than the MTU should be split up into MTU size units.
For e.g. a 1024 byte packet trying to cross a 576 byte MTU link should get split into 2 packets of 576 bytes and 448 bytes.

Throws:

NullPointerException - This happens when name is null or empty

ParameterException - This happens for the following conditions:

• name is null
• baudRate <= 0
• propDelay <= 0
• MTU <= 0

Pre Condition:

name != null, baudRate > 0, propDelay > 0, MTU > 0

Post Condition:

$none

Method Detail

attach

public abstract void attach(Sim_entity end1,
                            Sim_entity end2)

Connects two entities using this link. Any data sent through one end of this link will be sent out through the other.

Parameters:

end1 - Entity attached to one end of the Link

end2 - Entity attached to the other end of the Link

Pre Condition:

end1 != null, end2 != null

Post Condition:

$none

attach

public abstract void attach(String end1,
                            String end2)

Connects two entities using this link. Any data sent through one end of this link will be sent out through the other.

Parameters:

end1 - Entity attached to one end of the Link

end2 - Entity attached to the other end of the Link

Pre Condition:

end1 != null, end2 != null

Post Condition:

$none

getBaudRate

public double getBaudRate()

Returns the baud rate of the link in bits/s.

Returns:

the baud rate (bits/s)

Pre Condition:

$none

Post Condition:

$none

getDelay

public double getDelay()

Returns the tramssion delay that this link introduces.

Returns:

tranmission delay in milliseconds

Pre Condition:

$none

Post Condition:

$none

getMTU

public int getMTU()

Returns the Maximum Transmission Unit of this Link

Returns:

MTU in bytes

Pre Condition:

$none

Post Condition:

$none