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Network Working Group                                        D. WaitzmanRequest for Comments: 1149                                       BBN STC                                                            1 April 1990A Standard for the Transmission of IP Datagrams on Avian CarriersStatus 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-Waitzman                                                        [Page 1]

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: dwaitzman@BBN.COMWaitzman                                                        [Page 2]