A flooding algorithm is a method for distributing material to every part of a connected system. The name derives from the concept of inundation by a flood.
There are several variants of flooding algorithms: the one used on Usenet works as follows. Each node acts as both a transmitter and a receiver.
As a transmitter:
For each piece of information stored locally:
- For each neighbor:
- If the piece of information is not marked as being delivered to you via that neighbor:
- Check with them if they have it, and deliver it if they have not.
- If the piece of information is not marked as being delivered to you via that neighbor:
As a receiver:
For each transfer attempt from a neighbor:
- If already recieved, decline delivery
- Otherwise, receive, and mark as having been delivered from that neighbor.