Intended status: Standards Track A.Eromenko September 2016
draft-eromenko-ipff-fdp-00

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INTERNET-DRAFT
"Internet Protocol Five Fields - Fragmented Datagram Protocol", 
Alexey Eromenko, 2016-09-29, 
<draft-eromenko-ipff-fdp-00.txt>
expiration date: 2017-03-29

Intended status: Standards Track
                                                              A.Eromenko
                                                          September 2016

                      Fragmented Datagram Protocol
                    --------------------------------
                 for Internet Protocol "Five Fields" (IP-FF)
                          Specification draft

Abstract

A heavy-weight version of the UDP protocol, intended to provide simple
 fragmentation mechanism with Internet Protocol "Five Fields", along 
 with a stronger checksum at a cost of somewhat higher overhead.

Status of This Memo

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   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   described in the Simplified BSD License.

Introduction
------------

This Fragmented Datagram  Protocol  (FDP)  is  defined  to  make  
datagram   mode  communication possible in  the computing environment,
  where fragmented transmission and reception are needed.
FDP conceptually is a heavy-weight UDP if you will.

Format
------
                   Fragmented Datagram Header Format

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  4|                                                               |
   +                       CRC64c Checksum                         +
  8|                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 12|M|       Fragment Offset       |                               |
   |F|                             |                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 16|                       Fragment Identifier                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                          data octets ...                      .
   |                                                               .
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
(bytes)

Fields
------

   CRC64c Checksum (64-bit)  -- 64-bit checksum. See CRC64 Checksum.

   M flag               1 = more fragments; 0 = last fragment.

   Fragment Offset      15-bit unsigned integer.  The offset, in 8-byte
                        units, of the data following this header,
                        relative to the start of the datagram.

   Fragment Identifier  48-bit identifier is needed to distinguish
                        fragments from different datagrams.

   FDP segment must only be assembled when the six-tuple matches:
   1. Source and Destination IP address
   2. Source and Destination ports / Flow
   3. Protocol
   4. Same Fragment Identifier

   *NOTE: Fragmentation is incompatible with very big Jumbograms. 
   (IP packets sized > 256 KiB)

CRC64 Checksum
--------------

   Consists of parts of the IP header, the FDP header, 
   and the data,  padded  with zero bytes  at the end (if  necessary)
   to  make  a multiple of two bytes.
   This checksum procedure is similar to what is used in TCP.64.

   If the computed  checksum  is zero,  it is transmitted  as all ones.
   An all zero  transmitted checksum  value means that the transmitter
   generated  no checksum  (for debugging or for higher level protocols
   that don't care or for ILNP purposes).

   Design note:
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