path: root/doc/rfc/rfc6217.txt

Independent Submission                                         T. Ritter
Request for Comments: 6217                                  1 April 2011
Category: Experimental
ISSN: 2070-1721


           Regional Broadcast Using an Atmospheric Link Layer

Abstract

   Broadcasting is a technology that has been largely discarded in favor
   of technologies like multicast.  This document builds on RFC 919 and
   describes a more efficient routing mechanism for broadcast packets
   destined for multiple Local Area Networks (LANs) or Metropolitan Area
   Networks (MANs) using an alternative link layer.  It significantly
   reduces congestion on network equipment and does not require
   additional physical infrastructure investment.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6217.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.






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Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................2
   3. Limitations .....................................................2
   4. Physical Layer ..................................................3
   5. Frame Format in the OSI Model ...................................3
      5.1. Data Link Layer ............................................3
      5.2. Network Layer ..............................................3
      5.3. Transport Layer ............................................4
   6. Reception .......................................................6
   7. Datagram Transmission ...........................................6
      7.1. Chemical Approach to the Atmospheric Link Layer ............6
      7.2. Location ...................................................7
      7.3. Physical Layer Conditions ..................................7
   8. References ......................................................8
      8.1. Normative References .......................................8
      8.2. Informative References .....................................8

1.  Introduction

   RFC 919 [1] defines a method for broadcasting packets to a local
   network.  It assumes that data link layers support efficient
   broadcasting.  In the years since RFC 919 was written, Local Area
   Networks have grown exponentially in size, and frequently they are
   not geographically local.

   This RFC proposes a new data link layer that scales efficiently to a
   geographically local network and, depending on visibility, to an
   entire Metropolitan Area Network.  By using a different transmission
   medium, the broadcast traffic does not impact current inter- or
   intra-network routed traffic.  It also makes use of a widely
   available infrastructure that is in use in all major cities and,
   surprisingly, rural and under-developed locations as well.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.

3.  Limitations

   This RFC does not propose solutions to all problems.  Just as RFC 919
   was unconcerned with reliability, we also do not guarantee that hosts
   receive datagrams sent.  Hosts may not receive packets for a variety
   of reasons, among them weather conditions, line of sight, sleep
   patterns, and distraction.  A best-effort delivery approach is taken.



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   These limitations do impact the usefulness of the proposal, but
   organizations serious about distributing information in this fashion
   can overcome these obstacles with relatively little difficulty.

4.  Physical Layer

   The physical layer used is made up primarily of nitrogen and oxygen,
   at a pressure of 101.3 kilopascal at sea level, but dropping to about
   half that pressure at operating altitudes.  Microscopic residue or
   trace elements may exist in the transmission medium, depending on
   local formation properties.

   This residue may include argon, carbon dioxide, neon, helium,
   chloride anions, sulfur dioxide, and other molecules occurring at
   very low mixtures.  It is common for there to be some degree of
   gaseous dihydrogen monoxide present.  These trace molecules usually
   do not impede the broadcast, although further details on datagram
   transmission follow.

5.  Frame Format in the OSI Model

   It is always a challenge to design a protocol that allows enough
   flexibility for future adaptation while keeping it efficient in size
   -- and for this medium, size and complexity of the header are of
   particular concern.  For this reason, this RFC proposes
   recommendations for the Data Link, Network, and Transport Layers.

   Implementations MAY use any protocol that fits their needs for the
   Network and Transport Layers.  They SHOULD consider how different
   protocols may be interpreted by recipients of the message and choose
   the most effective protocol available.  The protocols defined have
   been designed to allow maximum ease of interpretation, so their use
   is encouraged.

5.1.  Data Link Layer

   The Data Link Layer is primarily concerned with transmitting
   datagrams between adjacent nodes, and it is unnecessary here since we
   only support broadcast transmission.  Implementers MUST NOT
   encapsulate packets in a link layer protocol.

5.2.  Network Layer

   When designing a protocol for the Network Layer, it makes sense to
   consider existing protocols in this layer and reference their
   strengths and weaknesses.  Looking at IPv4/6, we can see their header
   structures include several fields unnecessary for our purposes:




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   Destination, TTL (Time to Live), DSCP (Diffserv Code Point), ECN
   (Explicit Congestion Notification), Hop Limits, and so on.  We can
   design a much more compact protocol thusly:

      +-------------------------------+-----------------------------+
      |            Content            |           Source            |
      +-------------------------------+-----------------------------+

                     Figure 1: Layout of the Datagram

   Content - A variable-length field containing the encapsulation of
   higher-level protocols.

   Source - The sender of the message.  A transmission MUST choose one
   of the following representations of the source:
      - IPv4 address in dot-decimal notation (e.g., 192.168.1.1)
      - IPv6 address in standard notation (RFC 5952 [2])
      - telephone number in E.123 notation
      - electronic mail address in E.123 notation
      - Uniform Resource Identifier (RFC 3986 [3])
      - geographic address

   The Source field MUST be present -- to send a message anonymously, a
   sender MUST use one of the reserved entries of the different types.
   Reserved Entries for telephone numbers vary by region; for example,
   in North America they are 555-0100 to 555-0199.  Reserved entries for
   IPv4 (RFC 5735 [4]), IPv6 (RFC 5156 [5]), and URIs (RFC 2606 [6]) may
   be found in their respective RFCs.  The concept of a region defined
   by homogeneous communication characteristics has been put forward
   already in [7], so geographic addressing ambiguities may be resolved
   by community standards.

   Because the message is sent to a specific geographical region, more
   leniency is available in source addressing, but requirements may be
   imposed by higher-level protocols.

   We call this protocol the Asynchronous Dumb Visual Exchange of Raw
   Transmissions or ADVERT.

5.3.  Transport Layer

   Similar to the Network Layer, a Transport Layer protocol is able to
   omit several constructs that are used in existing Transport Layer
   protocols.  Consider TCP -- sequence, acknowledgement, and many of
   the flags are discarded as there will be no SYN, SYN/ACK, or ACK
   handshake in a broadcast message.  Likewise, fields such as Window
   Size and Urgent -- created primarily as a benefit to router
   manufacturers -- are unnecessary in this medium.



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   In fact, in the event of a plain text message, content SHOULD be
   embedded directly in the ADVERT Protocol without the need of a
   transport protocol.  Consider the following packet:

              Content                          Source
   +------------------------------------------------------------+
   | Lobster Dinner - only $14.99    500 Boardwalk, Pt Pleasant |
   +------------------------------------------------------------+

                 Figure 2: Example ADVERT Datagram

   For UTF-encoded payloads, one SHOULD use the default UTF-encoding so
   the packet is human-readable.  This will minimize accidental
   misinterpretation.  This transmission structure lends itself most
   easily to human-parsable messages.

   For messages intended to be responded to by a computer (for example,
   binary content), a Transport Layer protocol MUST be used, and an
   implementer SHOULD use UDP, as it is one of the more compact
   protocols available in this layer.  An implementer SHOULD encode the
   UDP ports, length, and checksum in base-10 (leading zeros omitted)
   and the data in Base64 encoding.  The Base64 encoding, combined with
   the UDP checksum, resolves ambiguities with trailing whitespace or
   non-printable characters.

   The usage of UDP or other protocols that compute a checksum over
   source and destination addresses necessitates the use of either an
   IPv4 or IPv6 address as the Source in the ADVERT Protocol.  The
   Destination address 255.255.255.255 MUST be used in the calculation
   of an IPv4-based checksum, as it has already been specified as a
   local hardware broadcast that must not be forwarded (RFC 919).  For
   IPv6, the All Nodes link-local multicast destination
   FF02:0:0:0:0:0:0:1 MUST be used, defined in RFC 4291 [8].

     ADVERT Datagram           UDP Embedded            Sample Data
   +-----------------+     +--------+--------+     +--------+--------+
   |                 |     |Src Port|Dst Port|     |      0 |     80 |
   |                 |     +--------+--------+     +--------+--------+
   |                 |     | Length |Checksum|     |     24 |  62670 |
   |   UDP Packet    |     +--------+--------+     +--------+--------+
   |                 |     |                 |     | R0VUIC8gSFRUUC8 |
   |                 |     |      Data       |     | xLjENCg0K       |
   |                 |     |                 |     |                 |
   +-----------------+     +-----------------+     +-----------------+
   |  Source Address |     |  Source Address |     |     203.0.113.8 |
   +-----------------+     +-----------------+     +-----------------+

   Figure 3: Example of Encapsulating Binary Data in an ADVERT Datagram



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6.  Reception

   Upon receipt, the datagram should be optically scanned into an
   electronically transmittable form, similar to the methods used in RFC
   1149 [9].  If present, any checksums SHOULD be computed and compared
   with supplied values.  If the checksum does not match, the packet
   MUST be discarded.

   Physical layers always have advantages and disadvantages depending on
   their condition, maintenance, prevalence, and economic factors; the
   atmosphere is no different.  The protocols defined herein do not
   specify a TTL specifically because it is often out of their control,
   and dependent on the conditions present.  The intrinsic TTL produces
   a curve of error rates where, after time, meaning cannot be
   deciphered from the datagram either because of a non-matching
   checksum or, in the absence of a checksum (such as the ADVERT
   protocol), because of an unintelligible transmission.  If the Source
   field is sufficiently distinguishable, the recipient MAY contact the
   sender for message clarification.  RFC 919 is in agreement in stating
   that broadcasts MUST NOT be assumed to have been reliably delivered.

   Reconsidering Figure 3, a broadcast HTTP Request is sent, and
   recipients should return the request from each of their computer
   systems that are listening on the requisite port.  It is important to
   remember the security implications of the systems' acceptance of data
   from unknown senders.  It is the responsibility of each organization
   to utilize host-protection mechanisms and egress filtering to avoid
   exposing their systems to undue risk or exposing internal or NAT-ed
   devices.

   Although it may be easy for an operator to silently discard the
   packet, it would be inappropriate for a network operator to
   unilaterally discard data, in the absence of policy.  RFC 1087 [10]
   classifies an action that destroys the integrity of computer-based
   information as unethical and unacceptable; and the Code of Ethics of
   SAGE, USENIX, and LOPSA recognize the important of maintaining
   integrity, reliability, and availability.

7.  Datagram Transmission

7.1.  Chemical Approach to the Atmospheric Link Layer

   Information is sent by transmitters producing a specialized form of
   smoke, most often by emitting a specialized oil onto the exhaust
   manifold.  The oil, held in a pressurized container, is vaporized in
   a thick white smoke, producing readable display.  The makeup of the
   smoke is often subject to patents, and any organization interested
   should consult with their attorneys.  Further details on transmission



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   on the Physical Layer is beyond the scope of this RFC, but
   implementers MAY refer to references for help.  It is by design that
   the broadcast mechanism does not result in incompatibilities if
   implementers choose different Physical Layer implementations.

7.2.  Location

   The datagram MUST be displayed in the atmosphere, at an altitude of
   7000 to 17000 feet (2133 to 5181 meters).  It SHOULD be written using
   a "skytyping" method, similar to dot-matrix printing (Figure 4).
   This method will provide better persistence of the datagram in the
   presence of air currents.  Additionally, it provides the ability for
   parallelism by using additional avionic instruments.

                #######   #######   #######   #######
                   #      #            #      #
                   #      #            #      #
                   #      ####         #      ####
                   #      #            #      #
                   #      #            #      #
                #######   #######      #      #

               Figure 4: Skytyping Method in the Sky

   The most efficient method for broadcasting a datagram on this link
   layer is the hire of specialized companies that perform this service
   on a regular basis.  For a large organization interested in using
   this method frequently, it may be more cost-effective to develop
   one's own methods.

7.3.  Physical Layer Conditions

   Transmission ability varies by atmospheric and regional conditions.
   Adverse conditions, such as an accumulation of moisture or ice
   crystals in the Physical Layer, may preclude transmission for a
   period of time.  During these periods, it is suggested broadcasts be
   delayed, as higher-than-expected error rates may occur, and receivers
   may not be prepared to process the transmission immediately.

   Additionally, solar radiation conditions affect transmission in a
   predictable, cyclic manner.  Depending on latitude, the medium may be
   unusable for a lengthy period, during which alternate arrangements
   must be made.

   Conditions may worsen before, during, or after a transmission,
   resulting in higher-than-expected transmission error rates.  Regional
   operators should be familiar with their operating conditions and




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   consider the feasibility of implementing a casual or robust
   infrastructure on this transmission medium.  Some locales lend
   themselves better to regular operation than others.

8.  References

8.1.  Normative References

   [1]  Mogul, J., "Broadcasting Internet Datagrams", STD 5, RFC 919,
        October 1984.

8.2.  Informative References

   [2]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
        Address Text Representation", RFC 5952, August 2010.

   [3]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
        Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986,
        January 2005.

   [4]  Cotton, M. and L. Vegoda, "Special Use IPv4 Addresses", BCP 153,
        RFC 5735, January 2010.

   [5]  Blanchet, M., "Special-Use IPv6 Addresses", RFC 5156, April
        2008.

   [6]  Eastlake 3rd, D. and A. Panitz, "Reserved Top Level DNS Names",
        BCP 32, RFC 2606, June 1999.

   [7]  Hooke, A., "Interplanetary Internet", GSAW 2003,
        <http://sunset.usc.edu/gsaw/gsaw2003/s3/hooke.pdf>.

   [8]  Hinden, R. and S. Deering, "IP Version 6 Addressing
        Architecture", RFC 4291, February 2006.

   [9]  Waitzman, D., "Standard for the transmission of IP datagrams on
        avian carriers", RFC 1149, April 1 1990.

   [10] Defense Advanced Research Projects Agency and Internet
        Activities Board, "Ethics and the Internet", RFC 1087, January
        1989.










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Author's Address

   Thomas Ritter
   PO Box 541
   Hoboken, NJ 07030
   USA

   EMail: tom@ritter.vg
   URI:   http://ritter.vg










































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