Class Switch

java.lang.Object

Switch

All Implemented Interfaces:

Layer2Listener

public class Switch
extends java.lang.Object
implements Layer2Listener

Switch models a learning switch, with multiple ports, each connected to a bus, on which computers can connect. This class keeps a table of MAC <--> port bindings, so it can learn where MAC addresses "live". This class also contains a collection of SwitchPorts and a parallel collection of SwitchLightPanels, each of which monitors the "wire" that the port is connected to.

Constructor Summary

Constructors

Constructor and Description
Switch(int numports) Create a Switch with the given number of ports.

Method Summary

Modifier and Type	Method and Description
void	addOrUpdateBySrcMac(int macAddr, SwitchPort s) used when checking if a source mac is recorded in the macAddr table.
void	attachPort(SwitchPort pt, SwitchLightPanel panel) Add the given SwitchPort/SwitchLightPanel to our collection of ports/panels.
void	enQueueOnAllPortsExceptOne(SwitchPort port2Skip, Layer2Frame fr) send the given frame on all registered ports, except port2Skip.
Switch.MacTableEntry	findEntryByMac(int macAddr) return the entry for the given mac, or null if no entry exists.
void	frameReceived(Layer2Handler handler, Layer2Frame frame) Handle frames received on a switch port.
int	getNumPorts() return numPorts value
SwitchLightPanel	getPanel(int i) return the ith switch port panel
java.lang.String	macAddrTableString() return the MacAddrTable as a long string, one entry per line.
void	setListener(SwitchListener l) Store an object to receive a callback when a port is attached.

Methods inherited from class java.lang.Object

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

Constructor Detail

Switch

public Switch(int numports)

Create a Switch with the given number of ports. This method creates the internal arrays of SwitchPorts and SwitchLightPanels.

Method Detail

attachPort

public void attachPort(SwitchPort pt,
                       SwitchLightPanel panel)

Add the given SwitchPort/SwitchLightPanel to our collection of ports/panels. Register this object as a listener of the SwitchPort. Call a registered SwitchListener object's portAttached() method.

findEntryByMac

public Switch.MacTableEntry findEntryByMac(int macAddr)

return the entry for the given mac, or null if no entry exists.

addOrUpdateBySrcMac

public void addOrUpdateBySrcMac(int macAddr,
                                SwitchPort s)

used when checking if a source mac is recorded in the macAddr table. If it isn't there, add it. If it is there, make sure the associated switch port is correct.

enQueueOnAllPortsExceptOne

public void enQueueOnAllPortsExceptOne(SwitchPort port2Skip,
                                       Layer2Frame fr)

send the given frame on all registered ports, except port2Skip.

frameReceived

public void frameReceived(Layer2Handler handler,
                          Layer2Frame frame)

Handle frames received on a switch port. This is the "main" function of the switch. Algorithm: 1. Look in the macAddrTable for the srcMac. 1.1. If found, update the entry with the port the frame came in on. 1.2. Else: add an entry. 2. If the destMac is bcast, send to all ports except the incoming one. Return. 3. Look in the macAddrTable for the destMac. 3.1. If found, send the frame on the associated port. 3.2. Else, send the frame out on all ports, except the port the frame came in on.

Specified by:

frameReceived in interface Layer2Listener

getNumPorts

public int getNumPorts()

return numPorts value

getPanel

public SwitchLightPanel getPanel(int i)

return the ith switch port panel

setListener

public void setListener(SwitchListener l)

Store an object to receive a callback when a port is attached.

macAddrTableString

public java.lang.String macAddrTableString()

return the MacAddrTable as a long string, one entry per line. Each line shows the MAC address and portnumber, in a nice format.