RFC 1149 – Avian Carrier for IP Protocol;

   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.

 

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