Network Working Group                                        D. Waitzman
Request for Comments: 1149                                       BBN STC
                                                           1 April 1990


  A Standard for the Transmission of IP Datagrams on Avian Carriers

Status of this Memo

  This memo describes an experimental method for the encapsulation of
  IP datagrams in avian carriers.  This specification is primarily
  useful in Metropolitan Area Networks.  This is an experimental, not
  recommended standard.  Distribution of this memo is unlimited.

Overview and Rational

  Avian carriers can provide high delay, low throughput, and low
  altitude service.  The connection topology is limited to a single
  point-to-point path for each carrier, used with standard carriers,
  but many carriers can be used without significant interference with
  each other, outside of early spring.  This is because of the 3D ether
  space available to the carriers, in contrast to the 1D ether used by
  IEEE802.3.  The carriers have an intrinsic collision avoidance
  system, which increases availability.  Unlike some network
  technologies, such as packet radio, communication is not limited to
  line-of-sight distance.  Connection oriented service is available in
  some cities, usually based upon a central hub topology.

Frame Format

  The IP datagram is printed, on a small scroll of paper, in
  hexadecimal, with each octet separated by whitestuff and blackstuff.
  The scroll of paper is wrapped around one leg of the avian carrier.
  A band of duct tape is used to secure the datagram's edges.  The
  bandwidth is limited to the leg length.  The MTU is variable, and
  paradoxically, generally increases with increased carrier age.  A
  typical MTU is 256 milligrams.  Some datagram padding may be needed.

  Upon receipt, the duct tape is removed and the paper copy of the
  datagram is optically scanned into a electronically transmittable
  form.

Discussion

  Multiple types of service can be provided with a prioritized pecking
  order.  An additional property is built-in worm detection and
  eradication.  Because IP only guarantees best effort delivery, loss
  of a carrier can be tolerated.  With time, the carriers are self-



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RFC 1149             IP Datagrams on Avian Carriers         1 April 1990


  regenerating.  While broadcasting is not specified, storms can cause
  data loss.  There is persistent delivery retry, until the carrier
  drops.  Audit trails are automatically generated, and can often be
  found on logs and cable trays.

Security Considerations

  Security is not generally a problem in normal operation, but special
  measures must be taken (such as data encryption) when avian carriers
  are used in a tactical environment.

Author's Address

  David Waitzman
  BBN Systems and Technologies Corporation
  BBN Labs Division
  10 Moulton Street
  Cambridge, MA 02238

  Phone: (617) 873-4323

  EMail: [email protected]





























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