1. Introduction

For the purposes of this document, an enterprise is an entity autonomously operating a network using TCP/IP and in particular determining the addressing plan and address assignments within that network.

This document describes address allocation for private internets. The allocation permits full network layer connectivity among all hosts inside an enterprise as well as among all public hosts of different enterprises. The cost of using private internet address space is the potentially costly effort of renumbering hosts and networks between public and private.

The decision of whether to adopt private internet address space is therefore a matter of organizational needs weighed against these costs. To facilitate this decision, it is necessary to enumerate the advantages and disadvantages of private internet address space as well as some operational considerations involved with the use of private internet address space.