Create overlay network

[David]

I just need to create a Pure P2P Network for data exchange between peers. But, first I need to evaluate regarding (delay, jitter, network traffic) and optimise the Pure P2P Network. And i also have to implement shortest path method for query processing between peers (optimisation part). How it could ne done ? Thank you !

[tobias amft]

Hi David,

before you start to implement your P2P Network, you should have a look on how simulations are configurated and started in the simulator:

Simulations in PeerfactSim.Kom are configured using a simple xml-file.
Please consider "chord.xml" in folder "config/visualization", which is structured as follows:
 - First, you can specify variables you want to use in this config-xml-file.
 - Next, you define and configure different layers you want to use: NetLayer, Translayer, Overlay, Application, and Monitor
 - Most Important: with the HostBuilder you define how many nodes to simulate and what layers each host/group comprises
 - As a last step you can choose between different churnmodels, and select an "actions-file"

In the actions file (here: config/visualization/chord-actions.dat) you can specify actions, a specific group should perform at given time
(Be aware that all nodes in the group perform this action.)
Note that actions in the action-file (in "chord-actions.dat": startLookups or ...:join) are implemented in the "component"- or "additionalClasses" you select in the xml-file (last few lines in "chord.xml")


As next step you can implement your P2P Application/Overlay.
Have a look into the file I attached to this method, there you find a basis you can use for your application.
Most important: applications have to register to the transport layer in order to be able to receive messages.

Also have a look at other applications or overlays that are implemented, e.g.
org.peerfact.impl.overlay.dht.chord.chord.components.ChordNode and
org.peerfact.impl.overlay.dht.chord.chord.components.ChordNodeFactory
(A Factory is used to install an application/overlay on your simulated host....)


Further, you should have a look at  org.peerfact.impl.overlay.dht.chord.chord.callbacks.joinOperation in order to learn how operations are used to send messages around.
- Make shure you understand how operations are executed and stopped (see org.peerfact.impl.common.AbstractOperation)
- Try to understand how callbacks (org.peerfact.api.common.OperationCallback) are used in combination with (Abstract)operations.
Operations can implement a "TransMessageCallback" to be able to receive messages and to wait for a message for a given time.
- Have a look at org.peerfact.api.transport.TransLayer: there you find all different send messages you can use to send(and wait for) a message.

If you follow these steps and if you have a look at existing Chord or Gnutella implementation, you have all the basics to implement your own application.

Hope this helps...