Network Working Group                                           D. Green
Request for Comments: 1679                                       P. Irey
Category: Informational                                        D. Marlow
                                                           K. O'Donoghue
                                                             August 1994

     HPN Working Group Input to the IPng Requirements Solicitation

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.


   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 mailing list.

Executive Summary

   The Navy's High Performance Network (HPN) working group has studied
   the requirements of mission critical applications on Navy platforms.
   Based on this study, three basic categories of issues for IPng have
   been identified.  The assumptions identified include accommodation of
   current functionality, commercial viability, and transitioning. The
   general requirements identified include addressing, integrated
   services architecture, mobility, multicast, and rapid route
   reconfiguration. Finally, the additional considerations identified
   include fault tolerance, policy based routing, security, and time
   synchroniztion. The HPN working group is interested in participating
   with the IETF in the development of standards which would apply to
   mission critical systems. In particular, the HPN working group is
   interested in the development of multicast functionality, an
   integrated services architecture, and support for high performance

1.   Introduction

   The HPN working group has been established to study future network
   architectures for mission critical applications aboard Navy
   platforms.  As a result, the HPN working group is interested in the
   results of the IPng selection and development process. This document
   is a product of discussions within the HPN working group.

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RFC 1679                 HPN IPng Requirements               August 1994

   The purpose of this document is to provide what the HPN working group
   perceives as requirements for an IPng protocol set. Many of the
   necessary capabilities exist in current Internet and ISO network
   protocols; however, the HPN working group has identified needed
   capabilities that are beyond the existing standards.

   The HPN working group has identified three categories of topics for
   discussion in this document. The first category is assumptions or
   those topics that the HPN working group believes the IPng process
   will solve satisfactorily without specific Navy input. The second
   category is general requirements. These are capabilities that are
   felt to be insufficiently addressed in existing network protocols and
   of key importance to Navy mission critical applications. Finally, a
   set of additional considerations has been identified. These are also
   issues of importance to the HPN working group. However, no guidance
   or specific requests can be provided at this time.

2.   Background

   The US Navy has set up a program through the Space and Naval Warfare
   Systems Command called the Next Generation Computer Resources (NGCR)
   Program. The purpose of this program is to identify the evolving
   needs for information system technology in Navy mission critical
   systems. The NGCR High Performance Network (HPN) working group was
   recently established by the NGCR program to examine high performance
   networks for use on future Navy platforms (aircraft, surface ships,
   submarines, and certain shore-based applications). This working group
   is currently reviewing Navy needs. The requirements provided below
   are based on the HPN working group's current understanding of these
   Navy application areas. The application areas of interest are further
   examined below. The time frame for design, development, and
   deployment of HPN based systems and subsystems is 1996 into the
   twenty first century.

   Three general problem domains have been identified by the HPN working
   group. These are the particular problem domains within a mission
   critical environment that the HPN working group is targeting. The
   first is a distributed combat system environment.  This problem
   domain is analogous to a collection of workstations involved in many
   varied applications involving multiple sources and types of
   information.  Analog, audio, digital, discrete, graphic, textual,
   video, and voice information must be coordinated in order to present
   a single concise view to a commander, operator, or any end user. The
   second problem area highlights the general internetworking
   environment. The task of moving information to many heterogeneous
   systems over various subnetworks is addressed. Finally, the problem
   of providing a high speed interconnect for devices such as sensors
   and signal processors is identified. [1]

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RFC 1679                 HPN IPng Requirements               August 1994

2.1   Application Area

   The application area of HPN is the communication network which is a
   component of the mission critical systems of Navy platforms. The
   expected end points or users of the HPN include humans, computers,
   and the many devices (cameras, etc.) found on such platforms. The
   function of these end points includes sensor input, signal
   processors, operator consoles, navigation systems, etc. The endpoints
   are typically grouped into systems both on platforms and at shore-
   based sites. These systems perform functions including long range
   planning, analysis of sensor information, and machinery control in

   Information types that have been identified as required by the HPN
   working group include voice, live and pre-recorded audio ranging from
   voice to CD quality (e.g., from sensors), video (1 to 30 frames per
   second in both monochrome and color), image data (static or from
   real-time sensors), reliable and connectionless data transfer, and
   very high-bandwidth (gigabits per second) unprocessed sensor data.

2.2   Services

   Another way of categorizing the HPN application area is by
   considering the user services that need to be supported. Some of
   these services are the following:

     1.   process to process message passing

     2.   distributed file and database manipulation

     3.   e-mail (both within the platform and off the platform)

     4.   teleconferencing (with the platform, between platforms, and
          across the Internet)

     5.   video monitoring of various physical environments

     6.   voice distribution (as a minimum between computer processes
          and people)

     7.   image services

     8.   time synchronization

     9.   name or directory services

     10.  network and system management

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     11.  security services (support of multilevel data security,
          privacy and protection)

3.   Assumptions

   The assumptions documented below are concerns that the HPN working
   group presumes will be accommodated in the IPng process.  However,
   they are of enough importance to this working group to merit

3.1   Accommodation of Current Functionality

   The IPng protocols need to provide for at least the existing
   functionality. In particular, the following issues have been

     1)   The IPng protocols need to provide for the basic
          connectionless transfer of information from one end-point to

     2)   The IPng protocols need to support multiple subnetwork
          technologies. This includes but is not limited to Ethernet,
          FDDI, Asynchronous Transfer Mode (ATM), Fiber Channel, and
          Scalable Coherent Interface (SCI). These are the subnetwork
          technologies that are of particular interest to the HPN
          working group. Ideally, IPng protocols should be subnetwork

     3)   The IPng protocols need to support hosts that may be
          multihomed. Multihomed in this context implies that a single
          host may support multiple different subnetwork technologies.
          Multihomed hosts must have the capability to steer the traffic
          to selected subnetworks.

     4)   The IPng process needs to recognize that IPng may be only one
          of several network protocols that a host utilizes.

     5)   The IPng process needs to provide for appropriate network
          management in the finished product. Network management is of
          vital importance to the applications of interest to the HPN
          working group.

3.2   Commercial Viability

   As is the case in the commercial world, the HPN working group feels
   strongly that the IPng protocols must be commercially viable. This
   includes but is not limited to the following issues:

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     1)   The IPng protocols must function correctly. The Navy cannot
          afford to have network protocol problems in mission critical
          systems. There must be a high degree of confidence that the
          protocols are technically sound and multi-vendor
          interoperability is achievable.

     2)   The IPng protocols must have the support of the
          commercial/industrial community. This may first be
          demonstrated by a strong consensus within the IETF community.

3.3   Transition Plan

   The Navy has a large number of existing networks including both
   Internet and ISO protocols as well as a number of proprietary
   systems.  As a minimum, the IPng effort must address how to
   transition from existing IP based networks. Additionally, it would be
   desirable to have some guidance for transitioning from other network
   protocols including, but not limited to, CLNP and other commonly used
   network protocols. The transition plan for IPng needs to recognize
   the large existing infrastructure and the lack of funds for a full
   scale immediate transition. There will, in all likelihood, be a long
   period of co-existence that should be addressed.

4.   General Requirements

   The general requirements documented below are topics that the HPN
   working group considers to be of vital importance in a network
   protocol solution. It is hoped that the IPng solution will address
   all of these issues.

4.1   Addressing

   The HPN working group has identified initial addressing requirements.
   First, a large number of addresses are required.  In particular, the
   number of addressable entities on a single platform will range from
   the 100's to 100,000. The number of large platforms (ships,
   submarines, shore based sites) will range from a few hundred to
   several thousand. In addition, there will be 500 to 1000 or more
   small platforms, primarily aircraft.  Since it is expected that in
   the future many of these platforms will be connected to global
   networks, the addresses must be globally unique.

   The second requirement identified is for some form of addressing
   structure. It is felt that this structure should be flexible enough
   to allow for logical structures (not necessarily geographical) to be
   applied. It is also felt that this is important for the
   implementation of efficient routing solutions.  In addition, the
   addressing structure must support multicast group addressing. At a

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RFC 1679                 HPN IPng Requirements               August 1994

   minimum 2**16 globally unique multicast groups must be
   distinguishable per platform.

4.2   Integrated Services Architecture

   An important goal of the HPN working group is to identify existing
   and emerging technologies which provide mechanisms for integrating
   the services required by mission critical Navy systems. The HPN
   working group has identified two classes of problems under the
   general category of integrated services. The first is to provide for
   the multiple types of services identified in section 2.1.  It is
   required to support these services in an integrated fashion in order
   to be able to correlate (in time) related streams of information.

   The second class of problems relates to the predictable management of
   the various traffic flows associated with the above identified
   services.  While many of these services require the delivery of a PDU
   within a specified time window, the applications in a mission
   critical environment can demand more stringent requirements. In areas
   where real-time systems are in use, such as machinery control,
   narrower and/or more predictable delivery windows may be required
   than in the case of the delivery of audio or video streams. The
   mission critical environment also requires the ability to assign
   end-to-end importance to instances of communications (i.e.,
   invocations of a particular service). For example, an ongoing video
   stream may need to yield to machinery control commands to ensure that
   the commands are received before their deadline.  The expense of this
   action is to degrade temporarily the video stream quality.

   The HPN working group is looking for mechanisms in the IPng protocols
   to provide for both of these classes of problems in an integrated
   fashion.  An integrated services architecture reduces design and
   integration complexities by providing a uniform set of tools for use
   by the mission critical system designer and application developer.
   Finally, the integrated services architecture must be flexible and
   scalable so that new services can be added in the future with minimum
   impact on systems using it.  The HPN working group has intentionally
   avoided mentioning particular mechanisms that can be used to solve
   some of these problems in order to avoid requiring a particular

4.3   Mobility

   The HPN working group has identified two classes of mobility for the
   Navy mission critical environment. First, most platforms are
   themselves mobile. As these platforms move from port to port or from
   flight deck to flight deck, it is important that they are able to
   communicate with a number of defense installations via a general

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RFC 1679                 HPN IPng Requirements               August 1994

   infrastructure.  Additionally, it is feasible that systems within a
   single platform may be mobile. Maintenance and damage assessment
   requires large amounts of information at numerous locations on a
   platform. This information could possibly be made available through
   mobile terminals.

4.4   Multicast

   Multicast transfer is a very critical IPng requirement for the Navy's
   mission critical systems. Aboard a Naval platform there are many
   hosts (e.g., workstations) connected via numerous subnetworks. These
   hosts are all working different aspects of the problem of keeping the
   platform operational to perform its mission. In support of this
   environment, multicast transfer is needed to share data that is
   needed by multiple hosts. For example, aboard a ship platform,
   environmental data (roll, pitch, heading...) is needed by almost all
   systems. Video conferencing may be used for communication among
   operational personnel at multiple places aboard this ship. Video
   conferencing could also be used for communicating with personnel on
   other platforms or at shore facilities.  Both of these examples, in
   addition to a number of DoD and NATO studies, have highlighted the
   need for multicast functionality in mission critical systems.

   One of the limiting factors with the present IP version 4 multicast
   is the optional nature of this multicast, particularly with respect
   to routers. The use of tunnels, while enabling the initial deployment
   of multicast in the Internet, appears to limit its potential. The HPN
   working group believes that the best approach to provision of
   multicast functionality is to consider it as a basic functionality to
   be provided by IPng. In addition, sensible mechanisms are needed to
   control multicast traffic (i.e., scope control). Finally, support is
   required to enable multicast functionality in IPng in areas such as
   group addressing and scalable multicast routing.

4.5   Rapid Route Reconfiguration

   The HPN project will be using very high bandwidth subnetwork
   technology.  In the mission critical environment one very important
   problem is placing a very low bound on the time it takes to identify
   a subnetwork problem and to complete the necessary route
   reconfigurations. The Navy's mission critical environment needs to be
   able to trade-off bandwidth to enable a short
   detection/reconfiguration time on subnetwork faults. A maximum bound
   on this time is felt to be less than 1 second.

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RFC 1679                 HPN IPng Requirements               August 1994

5.   Additional considerations

   This section represents additional concerns of the mission critical
   environment which may impact IPng. The HPN working group felt that
   these issues are important for the mission critical environment;
   however, it was not clear how or whether it is necessary to
   accommodate them in IPng solutions. It may suffice that designers of
   IPng are aware of these issues and therefore do not preclude
   reasonable solutions to these problems.

5.1   Fault Tolerance

   The mission critical environment is particularly sensitive to the
   area of fault tolerance. Any mechanisms that can be accommodated
   within the IPng protocol set, including routing and management, to
   support various levels of fault tolerance are desirable. In
   particular, the following features should be supported: error
   detection, error reporting, traffic analysis, and status reporting.

5.2   Policy Based Routing

   The HPN working group feels that there may be some uses for policy
   based routing within the Navy's mission critical systems.  The
   primary interest is in support of a very capable security facility.
   Other uses discussed are as a means for keeping certain types of data
   on certain subnetworks (for multiply homed hosts) and providing for
   automatic reconfiguration in the event of particular subnetwork

5.3   Security

   Security is an important requirement for most Navy applications and
   thus the ability for the network functions to be designed to support
   security services are essential. The following are several security
   services in particular that the HPN working group believes the
   network function should be able to support:  rule based access
   control, labeling, authentication, audit, connection oriented and
   connectionless confidentiality, selective routing, traffic flow
   confidentiality, connection oriented and connectionless integrity,
   denial of service protection, continuity of operations, and
   precedence/preemption.  In addition to these services, the network
   function should also support the security management of these
   security services. In particular, key management is of importance.

   Currently, the IPSEC of the IETF has several draft memos being
   considered to incorporate various security services in the network
   functions. It is of concern to the HPN working group that the IPng be
   able to support the concepts currently being developed by the IPSEC

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RFC 1679                 HPN IPng Requirements               August 1994

   and also provide the ability for the addition of future security

5.4   Time Synchronization

   Time synchronization among the various components of mission critical
   systems is of vital importance to the Navy. It is desirable to be
   able to synchronize systems on multiple subnetworks via a network
   layer infrastructure. Some hooks for time synchronization can be
   envisioned in the network layer.  However, the HPN working group
   feels that, as a minimum, efficient time synchronization algorithms
   must be able to function above an IPng infrastructure. For HPN
   systems, it is desirable that a time-of-day synchronization
   capability be supported of at least an accuracy of one microsecond
   among all hosts in a platform or campus network. The IPng protocols
   should not arbitrarily prevent this type of synchronization

6.   Conclusions

   A number of concerns specific to mission critical systems targeted by
   the HPN working group have been identified. The HPN working group is
   interested in participating with the IETF in the development of
   standards which would apply to mission critical systems. In
   particular, the HPN working group is interested in the development of
   multicast functionality, an integrated services architecture, and
   support for high performance subnetworks.

7.   References

   [1] HPN Planning Group, "Concepts and Guidance for High Performance
       Network (HPN)", Work in Progress, May 17, 1993.

8.  Security Considerations

   Security issues are discussed in Section 5.3.

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RFC 1679                 HPN IPng Requirements               August 1994

9.   Authors' Addresses

   Dan Green
   Code B35 NSWCDD
   Dahlgren, VA 22448

   Phone: (703) 663-1571

   Phil Irey
   Code B35 NSWCDD
   Dahlgren, VA 22448

   Phone: (703) 663-1571

   Dave Marlow
   Code B35 NSWCDD
   Dahlgren, VA 22448

   Phone: (703) 663-1571

   Karen O'Donoghue
   Code B35 NSWCDD
   Dahlgren, VA 22448

   Phone: (703) 663-1571

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