Keywords: SCAMP, scalable membership, gossip, epidemic dissemination, WebRTC

This project is an attempt to provide a full browser gossip protocol with random peer sampling. More specifically, it implements the Scalable Membership Protocol (SCAMP) [1] which is a gossip that automatically resizes its neighbourhood tables in order to fit with the size of the network using local knowledge only.

The Project rtc-SCAMP uses WebRTC which allows creating peer-to-peer connections within the browser. To our knowledge, there do not exist any implementations which do not rely on a central server to ease the initialisation phase of the membership. Thus, this project aims to fill this gap. Such implementation would allow building distributed network by only manually sharing a piece of data (e.g. by mail).

You can get the module using the node packet manager: $ npm install rtc-scamp

Or using bower: $ bower install rtc-scamp

This module creates a network which implements the p2pnetwork API. It uses rtc-scamp-mbr for the membership part, i.e., how a peer can join the network. It uses simple-broadcast-definition for the epidemic dissemination of messages which collects the unique identifier of each message so they are broadcast only once.

The example is hosted here. The code can be found on the gh-branch of this project. To use it, follow the steps:

1. Open the link with any WebRTC compatible web browser (e.g. Chrome)
2. Click on "1. Make offer". 3 seconds later, a string appears in the text area. Copy the string.
3. Open a new tab with the same link and paste the string inside the empty textarea.
4. Click on "2. Accept offer". 3 seconds later, the string in the text area changes. Copy the string.
5. In the first tab, erase the text area and paste string.
6. Click on "3. Confirm handshake"
7. The connection has started between the two tabs

To connect more peers, follow the same process: create a new tab, generate the offer, copy it to a tab which is already connected to the network and click on "2. Accept offer". Few seconds later, the text changes. Copy it to the new tab and "3. Handshake". The peer is now connected to the network.

In this example, each peer regularly broadcasts their name. Also, when they receive a broadcast message, they print it in the page. Normally, in each connected tab, the name of every other peers should appear.

[1] Peer-to-Peer Membership Management for Gossip-Based Protocols