theory.txt

Anuko Hub

The goal of this project is to design a simple yet reasonably reliable message delivery mechanism
for other applications such as Anuko Auction Server or others.

The point is to "network" an otherwise standalone server with similar servers via such hubs.

Servers then obtain a capability to expose their services to users at other locations.
For example, a user registered with server A can bid on items listed on server B, and so on.

Hub does not know about message content. Therefore, it can connect different types of servers
together, such as auction servers, freelance job servers, stock photo servers, etc.


REDUNDANCY

We aim at achieving some redundancy in the following way:
- Hubs may use multiple upstream hubs (by configuring them so).
- Hubs that receive a message attempt to transmit it to its downstream and upstream hubs.
- Duplicate messages are processed only once by each hub.
- Undelivered messages are retried a reasonable number of times, then discarded.


HUB INITIALIZATION

At startup, a hub should contact upstream nodes and tell them about itself.


MESSAGE PROCESSING

- If a message is a duplicate, it is discarded.
- Hub attempts to deliver the message to localhost.
- Hub attempts to deliver the message to all upstream and downstream hubs.
- If all retries to a downstream hub fail, it is deactivated and excluded from further messages,
until it reactivates itself.