rfc1677.txt

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Network Working Group                                         B. Adamson
Request for Comments: 1677                     Naval Research Laboratory
Category: Informational                                      August 1994


      Tactical Radio Frequency Communication Requirements for IPng

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This document was submitted to the IETF IPng area in response to RFC
   1550.  Publication of this document does not imply acceptance by the
   IPng area of any ideas expressed within.  Comments should be
   submitted to the [e-mail] mailing list.

Executive Summary

   The U.S. Navy has several efforts exploring the applicability of
   commercial internetworking technology to tactical RF networks.  Some
   these include the NATO Communication System Network Interoperability
   (CSNI) project, the Naval Research Laboratory Data/Voice Integration
   Advanced Technology Demonstration (D/V ATD), and the Navy
   Communication Support System (CSS) architecture development.

   Critical requirements have been identified for security, mobility,
   real-time data delivery applications, multicast, and quality-of-
   service and policy based routing.  Address scaling for Navy
   application of internet technology will include potentially very
   large numbers of local (intra-platform) distributed information and
   weapons systems and a smaller number of nodes requiring global
   connectivity.  The flexibility of the current Internet Protocol (IP)
   for supporting widely different communication media should be
   preserved to meet the needs of the highly heterogeneous networks of
   the tactical environment.  Compact protocol headers are necessary for
   efficient data transfer on the relatively-low throughput RF systems.
   Mechanisms which can  enhance the effectiveness of an internet
   datagram protocol to provide resource reservation, priority, and
   service quality guarantees are also very important.  The broadcast
   nature of many RF networks and the need for broad dissemination of
   information to warfighting participants makes multicast the general
   case for information flow in the tactical environment.





Adamson                                                         [Page 1]

RFC 1677             IPng Tactical RF Requirements           August 1994


Background

   This paper describes requirements for Internet Protocol next
   generation (IPng) candidates with respect to their application to
   military tactical radio frequency (RF) communication networks.  The
   foundation for these requirements are experiences in the NATO
   Communication System Network Interoperability (CSNI) project, the
   Naval Research Laboratory Data/Voice Integration Advanced Technology
   Demonstration (D/V ATD), and the Navy Communication Support System
   (CSS) architecture development.

   The goal of the CSNI project is to apply internetworking technology
   to facilitate multi-national interoperability for typical military
   communication applications (e.g., electronic messaging, tactical data
   exchange, and digital voice) on typical tactical RF communication
   links and networks.  The International Standard Organization (ISO)
   Open Systems Interconnect (OSI) protocol suite, including the
   Connectionless Network Protocol (CLNP), was selected for this project
   for policy reasons.  This paper will address design issues
   encountered in meeting the project goals with this particular
   protocol stack.

   The D/V ATD is focused on demonstrating  a survivable, self-
   configuring, self-recovering RF subnetwork technology capable of
   simultaneously supporting data delivery, including message transfer,
   imagery, and tactical data, and real-time digital voice applications.
   Support for real-time interactive communication applications was
   extended to include a "white board" and other similar applications.
   IP datagram delivery is also planned as part of this demonstration
   system.

   The CSS architecture will provide U.S. Navy tactical platforms with a
   broad array of user-transparent voice and data information exchange
   services.  This will include support for sharing and management of
   limited platform communication resources among multiple warfighting
   communities.  Emphasis is placed on attaining interoperability with
   other military services and foreign allies.  Utilization of
   commercial off-the-shelf communications products to take advantage of
   existing economies of scale is important to make any resulting system
   design affordable.  It is anticipated that open, voluntary standards,
   and flexible communication protocols, such as IP, will play a key
   role in meeting the goals of this architecture.

Introduction

   Before addressing any IPng requirements as applied to tactical RF
   communications, it is necessary to define what this paper means by
   "IPng requirements".  To maintain brevity, this paper will focus on



Adamson                                                         [Page 2]

RFC 1677             IPng Tactical RF Requirements           August 1994


   criteria related specifically to the design of an OSI model's Layer 3
   protocol format and a few other areas suggested by RFC 1550.  There
   are several additional areas of concern in applying internetwork
   protocols to the military tactical RF setting including routing
   protocol design, address assignment, network management, and resource
   management.  While these areas are equally important, this paper will
   attempt to satisfy the purpose of RFC 1550 and address issues more
   directly applicable to selection of an IPng candidate.

Scaling

   The projection given in RFC 1550 that IPng should be able to deal
   with 10 to the 12th nodes is more than adequate in the face of
   military requirements.  More important is that it is possible to
   assign addresses efficiently.  For example, although a military
   platform may have a relatively small number of nodes with
   requirements to communicate with a larger, global infrastructure,
   there will likely be applications of IPng to management and control
   of distributed systems (e.g., specific radio communications equipment
   and processors, weapons systems, etc.) within the platform.  This
   local expansion of address space requirements may not necessarily
   need to be solved by "sheer numbers" of globally-unique addresses but
   perhaps by alternate delimitation of addressing to differentiate
   between globally-unique and locally-unique addressing.  The
   advantages of a compact internet address header are clear for
   relatively low capacity RF networks.

Timescale, Transition and Deployment

   The U.S. Navy and other services are only recently (the last few
   years) beginning to design and deploy systems utilizing open systems
   internetworking technology.  From this point of view, the time scale
   for selection of IPng must be somewhat rapid.  Otherwise, two
   transition phases will need to be suffered, 1) the move from unique,
   "stove pipe" systems to open, internetworked (e.g., IP) systems, and
   then 2) a transition from deployed IP-based systems to IPng.  In some
   sense, if an IPng is quickly accepted and widely implemented, the
   transition for tactical military systems will be somewhat easier than
   the enterprise Internet where a large investment in current IP
   already exists.  However, having said this, the Department of Defense
   as a whole already deploys a large number  of IP-capable systems, and
   the issue of transition from IP to IPng remains significant.

Security

   As with any military system, information security, including
   confidentiality and authenticity of data, is of paramount importance.
   With regards to IPng, network layer security mechanisms for tactical



Adamson                                                         [Page 3]

RFC 1677             IPng Tactical RF Requirements           August 1994


   RF networks generally important for authentication purposes,
   including routing protocol authentication, source authentication, and
   user network access control.  Concerns for denial of service attacks,
   traffic analysis monitoring, etc., usually dictate that tactical RF
   communication networks provide link layer security mechanisms.
   Compartmentalization and multiple levels of security for different
   users of common communication resources call for additional security
   mechanisms at the transport layer or above.  In the typical tactical
   RF environment, network layer confidentiality and, in some cases,
   even authentication becomes redundant with these other security
   mechanisms.

   The need for network layer security mechanisms becomes more critical
   when the military utilizes commercial telecommunications systems or
   has tactical systems inter-connected with commercial internets.
   While the Network Encryption Server (NES) works in this role today,
   there is a desire for a more integrated, higher performance solution
   in the future.  Thus, to meet the military requirement for
   confidentiality and authentication, an IPng candidate must be capable
   of operating in a secure manner when necessary, but also allow for
   efficient operation on low-throughput RF links when other security
   mechanisms are already in place.

   In either of these cases, key management is extremely important.
   Ideally, a common key management system could be used to provide key
   distribution for security mechanisms at any layer from the
   application to the link layer.  As a result, it is anticipated,
   however, that key distribution is a function of management, and
   should not dependent upon a particular IPng protocol format.

Mobility

   The definition of most tactical systems include mobility in some
   form.  Many tactical RF network designs provide means for members to
   join and leave particular RF subnets as their position changes.  For
   example, as a platform moves out of the RF line-of-sight (LOS) range,
   it may switch from a typical LOS RF media such as the ultra-high
   frequency (UHF) band to a long-haul RF media such as high frequency
   (HF) or satellite communication (SATCOM).

   In some cases, such as the D/V ATD network, the RF subnet will
   perform its own routing and management of this dynamic topology.
   This will be invisible to the internet protocol except for
   (hopefully) subtle changes to some routing metrics (e.g., more or
   less delay to reach a host).  In this instance, the RF subnetwork
   protocols serve as a buffer to the internet routing protocols and
   IPng will not need to be too concerned with mobility.




Adamson                                                         [Page 4]

RFC 1677             IPng Tactical RF Requirements           August 1994


   In other cases, however, the platform may make a dramatic change in
   position and require a major change in internet routing.  IPng must
   be able to support this situation.  It is recognized that an internet
   protocol may not be able to cope with large, rapid changes in
   topology.  Efforts will be made to minimize the frequency of this in
   a tactical RF communication architecture, but there are instances
   when a major change in topology is required.

   Furthermore, it should be realized that mobility in the tactical
   setting is not limited to individual nodes moving about, but that, in
   some cases, entire subnetworks may be moving.  An example of this is
   a Navy ship with multiple LANs on board, moving through the domains
   of different RF networks.  In some cases, the RF subnet will be
   moving, as in the case of an aircraft strike force, or Navy
   battlegroup.

Flows and Resource Reservation

   The tactical military has very real requirements for multi-media
   services across its shared and inter-connected RF networks.  This
   includes applications from digital secure voice integrated with
   applications such as "white boards" and position reporting for
   mission planning purposes to low-latency, high priority tactical data
   messages (target detection, identification, location and heading