simnet
Class ShortestPath

java.lang.Object
  simnet.RoutingTable
      simnet.ShortestPath

All Implemented Interfaces:

Pluggable, PlugoutListener

Direct Known Subclasses:

AggregateShortestPath

public class ShortestPath

extends RoutingTable

implements Pluggable

A routing table that uses global knowledge to route packets on the shortest path. If changes are made to the topology, the update shortest path (usp) command must be run.

Field Summary

private java.util.Hashtable	idx2ip For conversion between indicies and ip's.
private java.util.Hashtable	ip2idx For conversion between ip's and indicies.
private int[][]	link Link weight table
private int[]	path Shortest path table
private int[]	table Distances to destinations

Fields inherited from class simnet.RoutingTable

node, NODE_ID

Constructor Summary

ShortestPath()

Method Summary

private boolean	allSeen(boolean[] seen) Determines whether all Nodes have been seen.
boolean	applicableLink(Link l)
void	build() Generates a static and centralized routing table using Dijkstra' s shortest path algorithm.
private int	getClosest(int[] table, boolean[] seen) Determines the ID of the Node closest to the current Node that hasn' t been seen yet.
int	getDist(int to) This is a dirty hack needed for Speed Test (to test how well bandwidth and latency are modeled)
private int	idx(int ip) convert a node ip into an index
void	initialize(Node parent_node) Initializes a new ShortestPath routing table by initializing its num_nodes and links fields as well as its link and path arrays.
private int	ip(int idx) convert a node index into an ip
private boolean	isApplicableFromNATRouter(NATRouter nr, Link l)
private boolean	isApplicableRecursive(Link l)
int	lookup(int to) Determines the ID of the next hop in the path to the specified node.
boolean	prePlugout(java.lang.Object replacement) Don't need to do anything special to get removed or replaced.
private void	printTable(int[] table) Prints out an array (poorly named function).

Methods inherited from class simnet.RoutingTable

finalize, plugoutNotification

Methods inherited from class java.lang.Object

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

Field Detail

ip2idx

private java.util.Hashtable ip2idx

For conversion between ip's and indicies.

idx2ip

private java.util.Hashtable idx2ip

For conversion between indicies and ip's.

link

private int[][] link

Link weight table

path

private int[] path

Shortest path table

table

private int[] table

Distances to destinations

Constructor Detail

ShortestPath

public ShortestPath()

Method Detail

initialize

public void initialize(Node parent_node)

Initializes a new ShortestPath routing table by initializing its num_nodes and links fields as well as its link and path arrays.

Overrides:

initialize in class RoutingTable

Parameters:

parent_node - The Node this routing algorithm is running on

ip

private int ip(int idx)

convert a node index into an ip

idx

private int idx(int ip)

convert a node ip into an index

build

public void build()

Generates a static and centralized routing table using Dijkstra' s shortest path algorithm.

allSeen

private boolean allSeen(boolean[] seen)

Determines whether all Nodes have been seen.

Parameters:

seen - a boolean array used to keep track of which nodes have been seen

Returns:

TRUE if all nodes have been seen; FALSE otherwise

getClosest

private int getClosest(int[] table,
                       boolean[] seen)

Determines the ID of the Node closest to the current Node that hasn' t been seen yet.

Parameters:

table - the path table

seen - an array that keeps track of seen Nodes

lookup

public int lookup(int to)

Determines the ID of the next hop in the path to the specified node.

Specified by:

lookup in class RoutingTable

Parameters:

to - the end of the path

Returns:

the node ID of the next hop

getDist

public int getDist(int to)

This is a dirty hack needed for Speed Test (to test how well bandwidth and latency are modeled)

printTable

private void printTable(int[] table)

Prints out an array (poorly named function).

Parameters:

table - the table to print

applicableLink

public boolean applicableLink(Link l)

isApplicableRecursive

private boolean isApplicableRecursive(Link l)

isApplicableFromNATRouter

private boolean isApplicableFromNATRouter(NATRouter nr,
                                          Link l)

prePlugout

public boolean prePlugout(java.lang.Object replacement)

Don't need to do anything special to get removed or replaced.

Specified by:

prePlugout in interface Pluggable

Returns:

if this object can now be removed (was the operation sucessful)