In Single Player mode, ECS uses the settings the user has configured to control the ECS Engine. This works equally well in both the single missions and the campaign. In fact the ECS_client becomes the local ECS_server for the game.

In Multiplayer mode ECS_public variables on the ECS_client are overidden by the ECS_server and/or dedicated ECS_server. Also when a player (client) hosts an internet game, the ECS_server is not necessarily the host of the game, this is determined internally by ECS, therefore ECS_local settings should remain unaffected, however the ECS_public settings are determined by whomever becomes the host.

On a dedicated ECS_server, the ECS_clients are also subject to the ECS_public settings on the server. The dedicated ECS_server mod is a seperate download and only useable on a dedicated server.

The ECS engine provides a robust framework for advanced gameplay; while in multiplayer mode ECS is able to act as an ECS_client or ECS_server. Featuring a unique communications engine, this allows ECS to synchronise and communicate mission parameters and to determine the best host for the ECS_server, as well as supporting connect in progress and server re-negotiation on the fly between ECS_clients (except on a dedicated ECS_server).