Network Working Group                                          B. Kantor
Request for Comments: 1226                      Univ. of Calif San Diego
                                                               May 1991


           Internet Protocol Encapsulation of AX.25 Frames

Status of this Memo

  This memo describes a method for the encapsulation of AX.25 (the
  Amateur Packet-Radio Link-Layer Protocol) frames within IP packets.
  This technique is an Experimental Protocol for the Internet
  community.  Discussion and suggestions for improvement are requested.
  Please refer to the current edition of the "IAB Official Protocol
  Standards" for the standardization state and status of this protocol.
  Distribution of this memo is unlimited.

The AX.25 Amateur Packet-Radio Link-Layer Protocol

  The AX.25 Amateur Packet-Radio Link-Layer Protocol is described in
  the publication by that name [1], incorporated here by reference.

  Each AX.25 packet ("frame") is encapsulated in one IP datagram.
  Normally no AX.25 frame will exceed 330 octets, so fragmentation at
  the IP layer should not be necessary.  However, experiments with
  larger AX.25 frame sizes may require the use of standard IP
  fragmentation and reassembly procedures.

  When an AX.25 frame is encapsulated within an IP packet, HDLC framing
  elements (flags and zero-stuffing) are omitted, as the IP datagram
  adequately delimits the beginning and end of each AX.25 frame.  The
  16-bit CRC-CCITT frame check sequence (normally generated by the HDLC
  transmission hardware) is included.  In all other respects, AX.25
  frames are encapsulated unaltered.

  Each such IP datagram shall have a protocol number of 93.

Reference

  [1] AX.25 Amateur Packet-Radio Link-Layer Protocol Version 2.0
      October 1984.  Available from the American Radio Relay League,
      Newington CT USA 06111, and other sources.

Security Considerations

  Security issues are not discussed in this memo.





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RFC 1226            IP Encapsulation of AX.25 Frames            May 1991


Author's Address

  Brian Kantor
  University of California at San Diego
  Network Operations C-024
  La Jolla, CA 92093-0214

  Phone: (619) 534-6865

  EMail: [email protected]









































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