about simple_socket_server

The prefix 00:07:ED does indeed indicate a globally unique individual address, rather than a local address. This particular prefix is assigned to Altera (you can look up address prefix assignments at ieee oui and company id assignments (http://standards.ieee.org/regauth/oui/index.shtml)). Presumably, their example code uses the development board's serial number to generate a unique 3 byte value for the rest of the address.

If you're building your own hardware (so it doesn't come with an address assigned from Altera's block loke the development boards), you need to provide your own: a local address is a good solution for testing until you can get a block of globally unique addresses from the IEEE (see previous link).