Here an older article about a different Multiplayer concept:

Syncronous simulation

http://www.gamasutra.com/view/feature/3094/1500_archers_on_a_288_network_.php

This is a great choice for games that meet the following criteria:

-small amount of command senders / Players, (only have like 2 to 8 players)
-large amount of units (RTS as typical example, also other large simulations like in RPG games with many AI Players.
-instant reaction not as important (command to action delay)

The Syncronous simulation offers the advantage that the
network load is tiny, as only commands are send.
Each gameclient calculates the full game locally, based on
the commands.

Starcraft / Starcraft 2 also uses this approach.

(In case you wonder why replays cant simply jump
forward to any position. It requires to calculate
the whole gameflow constantly)