Realm Specific IP: Framework
RFC 3102

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Network Working Group                                           Editors:
Request for Comments: 3102                                    M. Borella
Category: Experimental                                         CommWorks
                                                                   J. Lo
                                                    Candlestick Networks
                                                           Contributors:
                                                            D. Grabelsky
                                                               CommWorks
                                                           G. Montenegro
                                                        Sun Microsystems
                                                            October 2001

                      Realm Specific IP: Framework

Status of this Memo

   This memo defines an Experimental Protocol for the Internet
   community.  It does not specify an Internet standard of any kind.
   Discussion and suggestions for improvement are requested.
   Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

IESG Note

   The IESG notes that the set of documents describing the RSIP
   technology imply significant host and gateway changes for a complete
   implementation.  In addition, the floating of port numbers can cause
   problems for some applications, preventing an RSIP-enabled host from
   interoperating transparently with existing applications in some cases
   (e.g., IPsec).  Finally, there may be significant operational
   complexities associated with using RSIP.  Some of these and other
   complications are outlined in section 6 of RFC 3102, as well as in
   the Appendices of RFC 3104.  Accordingly, the costs and benefits of
   using RSIP should be carefully weighed against other means of
   relieving address shortage.

Abstract

   This document examines the general framework of Realm Specific IP
   (RSIP).  RSIP is intended as a alternative to NAT in which the end-
   to-end integrity of packets is maintained.  We focus on
   implementation issues, deployment scenarios, and interaction with
   other layer-three protocols.

Borella, et al.               Experimental                      [Page 1]
RFC 3102                    RSIP: Framework                 October 2001

Table of Contents

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . .  2
   1.1. Document Scope  . . . . . . . . . . . . . . . . . . . . . .  4
   1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . .  4
   1.3. Specification of Requirements . . . . . . . . . . . . . . .  5
   2. Architecture  . . . . . . . . . . . . . . . . . . . . . . . .  6
   3. Requirements  . . . . . . . . . . . . . . . . . . . . . . . .  7
   3.1. Host and Gateway Requirements . . . . . . . . . . . . . . .  7
   3.2. Processing of Demultiplexing Fields . . . . . . . . . . . .  8
   3.3. RSIP Protocol Requirements and Recommendations  . . . . . .  9
   3.4. Interaction with DNS  . . . . . . . . . . . . . . . . . . . 10
   3.5. Locating RSIP Gateways  . . . . . . . . . . . . . . . . . . 11
   3.6. Implementation Considerations . . . . . . . . . . . . . . . 11
   4. Deployment  . . . . . . . . . . . . . . . . . . . . . . . . . 12
   4.1. Possible Deployment Scenarios . . . . . . . . . . . . . . . 12
   4.2. Cascaded RSIP and NAT . . . . . . . . . . . . . . . . . . . 14
   5. Interaction with Layer-Three Protocols  . . . . . . . . . . . 17
   5.1. IPSEC . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
   5.2. Mobile IP . . . . . . . . . . . . . . . . . . . . . . . . . 18
   5.3. Differentiated and Integrated Services  . . . . . . . . . . 18
   5.4. IP Multicast  . . . . . . . . . . . . . . . . . . . . . . . 21
   6. RSIP Complications  . . . . . . . . . . . . . . . . . . . . . 23
   6.1. Unnecessary TCP TIME_WAIT . . . . . . . . . . . . . . . . . 23
   6.2. ICMP State in RSIP Gateway  . . . . . . . . . . . . . . . . 23
   6.3. Fragmentation and IP Identification Field Collision . . . . 24
   6.4. Application Servers on RSAP-IP Hosts  . . . . . . . . . . . 24
   6.5. Determining Locality of Destinations from an RSIP Host. . . 25
   6.6. Implementing RSIP Host Deallocation . . . . . . . . . . . . 26
   6.7. Multi-Party Applications  . . . . . . . . . . . . . . . . . 26
   6.8. Scalability . . . . . . . . . . . . . . . . . . . . . . . . 27
   7. Security Considerations . . . . . . . . . . . . . . . . . . . 27
   8. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . 27
   9. References  . . . . . . . . . . . . . . . . . . . . . . . . . 28
   10. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 29
   11. Full Copyright Statement . . . . . . . . . . . . . . . . . . 30

1.  Introduction

   Network Address Translation (NAT) has become a popular mechanism of
   enabling the separation of addressing spaces. A NAT router must
   examine and change the network layer, and possibly the transport