PTIP system

PTIP stands for Position-To-IP. PTIP is a system for finding the IP addresses of hosts 'close' to a certain point in 'cyberspace'. You feed it a point in cyberspace, and it gives you back the IP address of a host running the PTIP protocol sufficiently close to the point.

PTIP allows my cyberspace to work by linking together hosts that are 'close' to each other in cyberspace so that they can send each other messages.

PTIP could be called a 'distributed database', like DNS which maps host names to ip addresses and is also a distributed database.

How the database is maintained

Each host running the PTIP protocol maintains a list of (host ip, host position, last time heard from host) tuples, where 'host position' is the position in cyberspace. The positions are kept up to date by each host sending UDP packets containing their position to all the hosts on its list. These packets will be sent every 10+ secs or so to each host.

Occasionally new hosts will be added to a host's list.

This list is currently maintained by the program DSPDaemon.exe.

How the mapping works

Say a host wants to know the IP addresses of the host closest to the point (100, 100, 100). The host, which I will call the initiator, looks through its list and finds the host closest to (100, 100, 100), using the usual euclidean distance. It sends a PTIP request packet off to this host. When this host gets the packet, it examines its list, and sends the packet onto the closest host in its list. This continues until the request reaches a host which is sufficiently close to the point, say 100 meters. This host will then contact the initiator host. The host will then proceed to synchronise with the initiator host until both hosts share a consistent world view.