The right description for most networks in finance isn't really private, but rather semi-public. NYSE's matching engines aren't routable over the public interne

The right description for most networks in finance isn't really private, but rather semi-public. NYSE's matching engines aren't routable over the public internet, but they'll give access to anybody willing to pay the price. Same goes for any of the hundreds of other exchanges out there. And lots of broker/dealers need to talk to multiple different exchanges, as well as to each other. It would be nice to do all of that communication using one globally unique IP address, rather than with a rats nest of NAT for each gateway.