Implementing Trust-to-Trust with Customer Edge Switching

A Network Address Translator allows hosts in a private address space to communicate with servers in the public Internet. There is no accepted solution for an arbitrary host from the public IP network to initiate communication with a host in a private address space although attempts have been made to create one. This paper proposes the replace NATs with a more comprehensive concept we call Customer Edge Switching (CES). Customer edge switching assumes connection state on the trust boundary between the user and the core networks. The connection state is managed by implicit signaling. The state gives means for the private network operator to apply elaborate access control to packet flows arriving from the Internet to the private network. CES is a way of moving from the end-to-end principle to the trust-to-trust principle advocated by Dave Clark.