Vivaldi View

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Azureuslogo3ds.gif This article is a part of the Azureus User Guide.
See UG_Statistics#Vivaldi_tab

The Vivaldi View is a visual representation of the Vivaldi system.

Contents

[edit] What is Vivaldi?

Vivaldi is a virtual positioning system. It computes a position for every peer in the system. Vivaldi is part of Azureus DHT. The purpose of Vivaldi is to predict ping times between nodes. In the Vivaldi system, the ping time should equal the distance between 2 peers.

[edit] How does it work?

Vivaldi is a distributed algorithm. There is no central server or node computing the position for everyone. Every peer computes its own Vivaldi position given other peers positions and times to ping them. As part of the DHT protocol, peers now exchange their Vivaldi position. Every time you contact a peer and get a reply from them, you update your position to find the best place where you fit in the Vivaldi coordinates.

[edit] What is the coordinates system being used?

We used Height Vector coordinates. Imagine a 2D field where people are positioned on the top of a stick. Your position on the field (x,y) and the height of the stick (h) represent your coordinates. The distance between two "points" is the sum of their height, plus the usual euclidean distance.

[edit] What is Vivaldi being used for?

At the moment, nothing but computing a position. When we know it works OK, and gives good results, we'll use it to find faster routes to search in the DHT. Vivaldi could improve the DHT responsiveness by 50%.

[edit] How efficient is Vivaldi?

We're still working on the inner algorithms, but Vivaldi already gives logical results, with US people on one side, and European people on the other. Australians, for example, are on the US side, just a bit further than USA itself. We guess that Australian Internet connections are relayed by USA.


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