Simple Unstructured Overlay Network
Web-Overlay includes an implementation of simple unstructured overlay network as an sample program.
This is a very simple unstructured overlay network.
- it runs on a Node.js and only has a CUI interface.
- it tries to keep at least 3 connections.
- it supports random walking and flooding.
How to play
Join
Open several terminal windows.
On the 1st terminal, run the initial node listening on port 8000.
% cd packages/unstructured
% node dist/unode.js http://localhost:8000
Started: NodeID=99d7428d, URL=http://localhost:8000
Command Line Usage:
status -- show connections
put key value -- store a key-value pair in this node
rw [--ttl=N] key -- search key by single random walk
flood [--ttl=N] key -- search key by flooding
99d7428d>
On the 2nd terminal, run the 2nd node that listens on port 8001. http://localhost:8000 is used as the URL of the introducer node. The 2nd node joins the overlay network of the 1st node.
% cd packages/unstructured
% node dist/unode.js http://localhost:8001 http://localhost:8000
Join more nodes likewise.
CUI
This program provides a simple CUI.
- “status” command shows connections.
- “put” command puts key-value pair in the local node.
- “flood” command searches by flooding.
- “rw” command searches by random walking.
Example:
Let us assume that there is 2 nodes, N1 and N2, in the overlay network.
Put some value in each node.
N1> put Japan Tokyo
N2> put Japan Osaka
Search by flooding. TTL (max hops) value can be changed with
--ttl option.
N1> flood Japan
TTL=3
Found value Tokyo at N1 (path=Path(N1))
Found value Osaka at N2 (path=Path(N1->N2))
Query Timeout
N1> flood --ttl=0 japan
TTL=0
Found value Tokyo at N1 (path=Path(N1))
Query Timeout
N1>
Search by random walking.
N1> rw Japan
TTL=3
Found value Tokyo at N1 (path=Path(N1))
N1>
Note that random walking finds at most single entry.
Complete Source Code
The complete source code is included in the packages/unstructured
directory.
You can view it online at https://github.com/abelab/web-overlay/blob/master/packages/unstructured/src/unode.ts.