Nasdaq Data & Architecture

[tharnett]

Does anyone have any good suggestions where you can learn more about how Nasdaq and ECN data is aggregated and then distributed? For instance, if you subscribe to Nasdaq right here with eSignal, what kind of data are you getting? ECN's incluced? Are we just getting trades from all these regional liquidity pools or are we getting thier quotes as well?
Also, if you know of a great place to learn how all this fits together I would be interested in your thoughts.
Thanks!

[ScottJ]

Hi Trevor,

While I'm no expert, I can probably lend some information on this topic. In our Market Depth window, we are supplying data from ECN's if they transmit the best bid or ask offer. To see the depth of quotes being offered within a particular ECN, you have to view their book (clicking on the ARCA or Island tab in a Depth window for ex ). Comingling all these books into one single view is the subject of a bit of controversy and litigation. Here's one place you can read more about that.

I'd also suggest a simple search using google with ECN and Nasdaq as the keywords.

Thanks.