rfc3103.txt

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Network Working Group                                         M. Borella
Request for Comments: 3103                                  D. Grabelsky
Category: Experimental                                         CommWorks
                                                                   J. Lo
                                                    Candlestick Networks
                                                            K. Taniguchi
                                                                 NEC USA
                                                            October 2001


               Realm Specific IP: Protocol Specification

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 the 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 presents a protocol with which to implement Realm
   Specific IP (RSIP).  The protocol defined herein allows negotiation
   of resources between an RSIP host and gateway, so that the host can
   lease some of the gateway's addressing parameters in order to
   establish a global network presence.  This protocol is designed to
   operate on the application layer and to use its own TCP or UDP port.
   In particular, the protocol allows a gateway to allocate addressing
   and control parameters to a host such that a flow policy can be
   enforced at the gateway.



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Table of Contents

   1. Introduction  . . . . . . . . . . . . . . . . . . . . . . . .  3
   2. Specification of Requirements . . . . . . . . . . . . . . . .  4
   3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4. Architecture  . . . . . . . . . . . . . . . . . . . . . . . .  5
   5. Transport Protocol  . . . . . . . . . . . . . . . . . . . . .  7
   6. Host / Gateway Relationships  . . . . . . . . . . . . . . . .  7
   7. Gateway Flow Policy and State . . . . . . . . . . . . . . . .  8
   7.1. Local Flow Policy . . . . . . . . . . . . . . . . . . . . .  9
   7.2. Remote Flow Policy  . . . . . . . . . . . . . . . . . . . .  9
   7.3. Gateway State . . . . . . . . . . . . . . . . . . . . . . . 10
   8. Parameter Specification and Formats . . . . . . . . . . . . . 11
   8.1. Address . . . . . . . . . . . . . . . . . . . . . . . . . . 11
   8.2. Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
   8.3. Lease Time  . . . . . . . . . . . . . . . . . . . . . . . . 13
   8.4. Client ID . . . . . . . . . . . . . . . . . . . . . . . . . 13
   8.5. Bind ID . . . . . . . . . . . . . . . . . . . . . . . . . . 13
   8.6. Tunnel Type . . . . . . . . . . . . . . . . . . . . . . . . 14
   8.7. RSIP Method . . . . . . . . . . . . . . . . . . . . . . . . 14
   8.8. 8.8.  Error . . . . . . . . . . . . . . . . . . . . . . . . 14
   8.9. Flow Policy . . . . . . . . . . . . . . . . . . . . . . . . 15
   8.10. Indicator  . . . . . . . . . . . . . . . . . . . . . . . . 15
   8.11. Message Counter  . . . . . . . . . . . . . . . . . . . . . 16
   8.12. Vendor Specific Parameter  . . . . . . . . . . . . . . . . 16
   9. Message Types . . . . . . . . . . . . . . . . . . . . . . . . 16
   9.1. ERROR_RESPONSE  . . . . . . . . . . . . . . . . . . . . . . 17
   9.2. REGISTER_REQUEST  . . . . . . . . . . . . . . . . . . . . . 18
   9.3. REGISTER_RESPONSE . . . . . . . . . . . . . . . . . . . . . 19
   9.4. DE-REGISTER_REQUEST . . . . . . . . . . . . . . . . . . . . 19
   9.5. DE-REGISTER_RESPONSE  . . . . . . . . . . . . . . . . . . . 20
   9.6. ASSIGN_REQUEST_RSA-IP . . . . . . . . . . . . . . . . . . . 21
   9.7. ASSIGN_RESPONSE_RSA-IP  . . . . . . . . . . . . . . . . . . 22
   9.8. ASSIGN_REQUEST_RSAP-IP  . . . . . . . . . . . . . . . . . . 23
   9.9. ASSIGN_RESPONSE_RSAP-IP . . . . . . . . . . . . . . . . . . 26
   9.10. EXTEND_REQUEST . . . . . . . . . . . . . . . . . . . . . . 27
   9.11. EXTEND_RESPONSE  . . . . . . . . . . . . . . . . . . . . . 28
   9.12. FREE_REQUEST . . . . . . . . . . . . . . . . . . . . . . . 28
   9.13. FREE_RESPONSE  . . . . . . . . . . . . . . . . . . . . . . 29
   9.14. QUERY_REQUEST  . . . . . . . . . . . . . . . . . . . . . . 30
   9.15. QUERY_RESPONSE . . . . . . . . . . . . . . . . . . . . . . 31
   9.16. LISTEN_REQUEST . . . . . . . . . . . . . . . . . . . . . . 32
   9.17. LISTEN_RESPONSE  . . . . . . . . . . . . . . . . . . . . . 35
   10. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 36
   10.1. Use of Message Counters  . . . . . . . . . . . . . . . . . 36
   10.2. RSIP Host and Gateway Failure Scenarios  . . . . . . . . . 37
   10.3. General Gateway Policy . . . . . . . . . . . . . . . . . . 38
   10.4. Errors Not From the RSIP Protocol  . . . . . . . . . . . . 39



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   10.5. Address and Port Requests and Allocation . . . . . . . . . 40
   10.6. Local Gateways and Flow Policy Interaction . . . . . . . . 40
   11. Security Considerations  . . . . . . . . . . . . . . . . . . 40
   12. IANA Considerations  . . . . . . . . . . . . . . . . . . . . 41
   13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 41
   14. Appendix A: RSIP Error Numbers . . . . . . . . . . . . . . . 42
   15. Appendix B: Message Types  . . . . . . . . . . . . . . . . . 44
   16. Appendix C: Example RSIP host/gateway transactions . . . . . 45
   17. Appendix D: Example RSIP host state diagram  . . . . . . . . 50
   18. References . . . . . . . . . . . . . . . . . . . . . . . . . 52
   19. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 53
   20. Full Copyright Statement . . . . . . . . . . . . . . . . . . 54

1.  Introduction

   Network Address Translation (NAT) has gained popularity as a method
   of separating public and private address spaces, and alleviating
   network address shortages.  A NAT translates the addresses of packets
   leaving a first routing realm to an address from a second routing
   realm, and performs the reverse function for packets entering the
   first routing realm from the second routing realm.  This translation
   is performed transparently to the hosts in either space, and may
   include modification of TCP/UDP port numbers and IP addresses in
   packets that traverse the NAT.

   While a NAT does not require hosts to be aware of the translation, it
   will require an application layer gateway (ALG) for any protocol that
   transmits IP addresses or port numbers in packet payloads (such as
   FTP).  Additionally, a NAT will not work with protocols that require
   IP addresses and ports to remain unmodified between the source and
   destination hosts, or protocols that prevent such modifications from
   occurring (such as some IPsec modes, or application-layer end-to-end
   encryption).

   An alternative to a NAT is an architecture that allows the hosts
   within the first (e.g., private) routing realm to directly use
   addresses and other routing parameters from the second (e.g., public)
   routing realm.  Thus, RSIP [RSIP-FRAME] has been defined as a method
   for address sharing that exhibits more transparency than NAT.  In
   particular, RSIP requires that an RSIP gateway (a router or gateway
   between the two realms) assign at least one address from the second
   routing realm, and perhaps some other resources, to each RSIP host.
   An RSIP host is a host in the first routing realm that needs to
   establish end-to-end connectivity to a host, entity or device in the
   second routing realm.  Thus, the second routing realm is not directly






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   accessible from the RSIP host, but this system allows packets to
   maintain their integrity from the RSIP host to their destination.
   ALGs are not required in the RSIP gateway.

   RSIP requires that hosts be modified so that they place some number
   of layer three, layer four or other values from those assigned by the
   RSIP gateway in each packet bound for the second routing realm.

   This document discusses a method for assigning parameters to an RSIP
   host from an RSIP gateway.  The requirements, scope, and
   applicability of RSIP, as well as its interaction with other layer 3
   protocols, are discussed in a companion framework document [RSIP-
   FRAME].  Extensions to this protocol that enable end-to-end IPsec are
   discussed in [RSIP-IPSEC].

2.  Specification of Requirements

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT",
   "SHALL", "SHALL NOT", "MAY" and "MAY NOT" that appear in this
   document are to be interpreted as described in [RFC2119].

3.  Terminology

   Private Realm

      A routing realm that uses private IP addresses from the ranges
      (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) specified in
      [RFC1918], or addresses that are non-routable from the Internet.

   Public Realm

      A routing realm with unique network addresses assigned by the
      Internet Assigned Number Authority (IANA) or an equivalent address
      registry.

   RSIP Host

      A host within the private realm that acquires publicly unique
      parameters from an RSIP gateway through the use of the RSIP
      client/server protocol.

   RSIP Gateway

      A router situated on the boundary between a private realm and a
      public realm and owns one or more public IP addresses.  An RSIP
      gateway is responsible for public parameter management and
      assignment to RSIP hosts.  An RSIP gateway may act as a NAT router
      for hosts within the private realm that are not RSIP enabled.



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   RSIP Client

      An application program that performs the client portion of the
      RSIP client/server protocol.  An RSIP client application MUST
      exist on all RSIP hosts, and MAY exist on RSIP gateways.

   RSIP Server

      An application program that performs the server portion of the
      RSIP client/server protocol.  An RSIP server application MUST
      exist on all RSIP gateways.

   RSA-IP: Realm Specific Address IP

      An RSIP method in which each RSIP host is allocated a unique IP
      address from the public realm.  Discussed in detail in [RSIP-
      FRAME]

   RSAP-IP: Realm Specific Address and Port IP

      An RSIP method in which each RSIP host is allocated an IP address
      (possibly shared with other RSIP hosts) and some number of per-
      address unique ports from the public realm.  Discussed in detail
      in [RSIP-FRAME]

   Binding

      An association of some combination of a local address, one or more
      local ports, a remote address, and a remote port with an RSIP
      host.

   Resource

      A general way to refer to an item that an RSIP host leases from an
      RSIP gateway; e.g., an address or port.

   All other terminology found in this document is consistent with that
   of [RFC2663] and [RSIP-FRAME].

4.  Architecture

   For simplicity, in the remainder of this document we will assume that
   the RSIP hosts in the first routing realm (network) use private
   (e.g., see [RFC1918]) IP addresses, and that the second routing realm
   (network) uses public IP addresses.  (This assumption is made without
   loss of generality and the ensuing discussion applies to more general





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   cases.)  The RSIP gateway connects the public and private realms and
   contains interfaces to both.  Other NAT terminology found in this
   document is defined in [RFC2663].

   The diagram below describes an exemplary reference architecture for
   RSIP.

      RSIP Host             RSIP Gateway                    Host

         Xa                    Na   Nb                      Yb
      [X]------( Addr sp. A )----[N]-----( Addr sp. B )-------[Y]
               (  Network   )            (  Network   )

   Hosts X and Y belong to different addressing realms A and B,
   respectively, and N is an RSIP gateway (which may also perform NAT
   functions).  N has two interfaces: Na on address space A, and Nb on
   address space B.  N may have a pool of addresses in address space B
   which it can assign to or lend to X and other hosts in address space

   A.  These addresses are not shown above, but they can be denoted as
   Nb1, Nb2, Nb3 and so on.

   Host X, needing to establish an end-to-end connection to a network
   entity Y situated within address space B, first negotiates and
   obtains assignment of the resources from the RSIP gateway.  Upon
   assignment of these parameters, the RSIP gateway creates a mapping,
   of X's addressing information and the assigned resources.  This
   binding enables the RSIP gateway to correctly de-multiplex and
   forward inbound traffic generated by Y for X.  A lease time is
   associated with each bind.

   Using the public parameters assigned by the RSIP gateway, RSIP hosts
   tunnel data packets across address space A to the RSIP gateway.  The
   RSIP gateway acts as the end point of such tunnels, stripping off the
   outer headers and routing the inner packets onto the public realm.