I found this in a book it explains all about ECN, i hope it will help :
"ECN is short for Electronic Communications Network, and forex brokers who fall into this category will usually charge a small trading fee or commission. Remember, there is no such thing as a free lunch, and whilst ‘free trading’ may appear attractive superficially, remember that the costs will be hidden in the spreads. The ECN broker can therefore be considered transparent. You have paid for a service, the trade, and the broker has made his or her money. In many ways this is just like trading stocks or futures. You are charged a commission and the trade is executed. An ECN broker in the forex world works in the same way. In return for this up front commission, they provide forex traders with a marketplace where all the participants, however large or small, can trade against each other by sending competing bids and offers into the system. In some ways, you can think of this as a ‘central exchange’ there traders buy and sell in complete anonymity and with transparency. All orders are matched between counter parties in real time, but in order for a forex trading broker to be classified as a true ECN, the brokerage must display something called DOM or ‘Depth of Market’ in a data window, to show clients their own order size within the system, and allow
other clients to trade against those orders. In other words, forex traders should be able to see the liquidity, and execute trades accordingly. Put simply, it means transparency!
ECN brokers will always offer variable spreads, and because they do not make their money on the spread between the bid and the ask, any trading style (including scalping) should be permitted. Some forex brokers do not permit this style of trading, and as you will see, when we reach the questions to ask, this is certainly on the list. In the last few years, the terms of trading have changed dramatically and there are key questions you need to ask before opening your account to guarantee that your style of trading is permitted by the broker.
An ECN broker can therefore be considered, in my view at any rate, as the purest form of broker. They make their money from the commissions charged and are therefore keen for their clients to succeed. After all, if you are successful then you will trade more actively and generate more commissions for the broker. It’s a win/win situation. However, many new forex traders have been ‘sold’ on the benefit of ‘free’ trading, and fail to realize the advantages of paying a small commission in return for a transparent and fair trading environment. It is only when forex traders have experienced their stops being hit with ‘market
spikes’, irrational market moves against their positions, and endless ‘server issues’, that these same traders begin to appreciate the benefits of a true ECN broker."
"ECN is short for Electronic Communications Network, and forex brokers who fall into this category will usually charge a small trading fee or commission. Remember, there is no such thing as a free lunch, and whilst ‘free trading’ may appear attractive superficially, remember that the costs will be hidden in the spreads. The ECN broker can therefore be considered transparent. You have paid for a service, the trade, and the broker has made his or her money. In many ways this is just like trading stocks or futures. You are charged a commission and the trade is executed. An ECN broker in the forex world works in the same way. In return for this up front commission, they provide forex traders with a marketplace where all the participants, however large or small, can trade against each other by sending competing bids and offers into the system. In some ways, you can think of this as a ‘central exchange’ there traders buy and sell in complete anonymity and with transparency. All orders are matched between counter parties in real time, but in order for a forex trading broker to be classified as a true ECN, the brokerage must display something called DOM or ‘Depth of Market’ in a data window, to show clients their own order size within the system, and allow
other clients to trade against those orders. In other words, forex traders should be able to see the liquidity, and execute trades accordingly. Put simply, it means transparency!
ECN brokers will always offer variable spreads, and because they do not make their money on the spread between the bid and the ask, any trading style (including scalping) should be permitted. Some forex brokers do not permit this style of trading, and as you will see, when we reach the questions to ask, this is certainly on the list. In the last few years, the terms of trading have changed dramatically and there are key questions you need to ask before opening your account to guarantee that your style of trading is permitted by the broker.
An ECN broker can therefore be considered, in my view at any rate, as the purest form of broker. They make their money from the commissions charged and are therefore keen for their clients to succeed. After all, if you are successful then you will trade more actively and generate more commissions for the broker. It’s a win/win situation. However, many new forex traders have been ‘sold’ on the benefit of ‘free’ trading, and fail to realize the advantages of paying a small commission in return for a transparent and fair trading environment. It is only when forex traders have experienced their stops being hit with ‘market
spikes’, irrational market moves against their positions, and endless ‘server issues’, that these same traders begin to appreciate the benefits of a true ECN broker."
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