You can easily scrap any or all of these protocols and introduce another. You could even plug in modules to support xS querying of Gnutella or Napster networks. Thus, xS can still succeed spectacularly even if all of its current network protocols suck. This frees developers to choose the language that best suits their components. Network Protocol xS is not particularly tied to any network protocol.
Every host is required to support a public protocol and a family protocol.
The only requirement for interopability is that the xS http protocol be supported as well as a fallback position. DXP is the Dax Exchange Protocol, a proprietary network protocol for high performance xS installations in LAN environments. The family protocol is the one computers in the same family will use to talk to each other. The public protocol is one that a host will use for connections from the world. A family server can, in this way, be put into a DMZ with port 80 access from the outside world, but high performance DXP access from the intranet without compromising the security of the network infrastructure.