Is there any difference between 'Level 2 quotes' and 'Limit Order Book'? Are they different words describing the same thing? i.e the buy and sell orders that are queued up with different market makers and ECNs waiting to be filled?
Level II Quotes is the real-time limit book feed of NASDAQ or OTCBB listed equities. Now, nearly all major securities except for bonds have real-time limit book feeds.
This is NASDAQ's branding since they were the first one to offer limit book feeds. All others label it differently, but they are all real-time limit book data feeds.