PEPINO: PEer-to-Peer network INspectOr

PEPINO is a graphical PEer-to-Peer network INspectOr running on top of P2PS, a structured overlay network using the Relaxed-Ring topology. The goal is to monitor the network by detecting failures, and by observing the messages sent between peers. A dynamic and self-organizing view of the network is presented to the user, who can interacts with it to inject failures or send messages in order to study the network protocols.

Since many systems implement DHT in different ways - in particular by choosing the finger table with a different strategy - PEPINO also helps to study three different strategies, in particular finger tables following the strategy of DKS, Tango, and Chord . A demo of PEPINO was shown in the Seventh IEEE international Conference on Peer-to-Peer Computing (P2P'07).


Some screen-shots are presented on this page to depicts some of the features of PEPINO. The following image shows a ring composed by 10 nodes. Arrows have different colours in order to present meaningful information. Green arrows represent successor pointers. Red ones correspond to predecessors. Blue arrows are fingers. On the bottom-right corner there are 3 buttons to organized the ring according to a particular colour. In the case of the image, predecessor pointers are followed to verified that no inconsistency is presented (correct sharing of responsibility). Fingers and other arrows are highlighted when the mouse is focus on top of a particular node.

One of the main features that differentiate the relaxed-ring from other structured overlay networks, is the ability of accepting nodes with connectivity problems forming branches annexed to the core ring. The following screen-shot organized the peers with respect to the successor pointer (green arrow). It is possible to observe peers painted in yellow as members of the cor ring, and white peers belonging to branches.

PEPINO not only visualizes the network as a ring of peers. It also shows the messages exchanged between nodes as it is depicted on the screen-shot here bellow. This feature is place at the resizable left side of the application. If the mouse is place over a message exchanged between to peers, all the other messages between them will be highlighted.