Network Working Group                                         H. Kennedy
Request for Comments: 3252                                      Mimezine
Category: Informational                                     1 April 2002


                 Binary Lexical Octet Ad-hoc Transport

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2002).  All Rights Reserved.

Abstract

   This document defines a reformulation of IP and two transport layer
   protocols (TCP and UDP) as XML applications.

1.   Introduction

1.1. Overview

   This document describes the Binary Lexical Octet Ad-hoc Transport
   (BLOAT): a reformulation of a widely-deployed network-layer protocol
   (IP [RFC791]), and two associated transport layer protocols (TCP
   [RFC793] and UDP [RFC768]) as XML [XML] applications.  It also
   describes methods for transporting BLOAT over Ethernet and IEEE 802
   networks as well as encapsulating BLOAT in IP for gatewaying BLOAT
   across the public Internet.

1.2. Motivation

   The wild popularity of XML as a basis for application-level protocols
   such as the Blocks Extensible Exchange Protocol [RFC3080], the Simple
   Object Access Protocol [SOAP], and Jabber [JABBER] prompted
   investigation into the possibility of extending the use of XML in the
   protocol stack.  Using XML at both the transport and network layer in
   addition to the application layer would provide for an amazing amount
   of power and flexibility while removing dependencies on proprietary
   and hard-to-understand binary protocols.  This protocol unification
   would also allow applications to use a single XML parser for all
   aspects of their operation, eliminating developer time spent figuring
   out the intricacies of each new protocol, and moving the hard work of




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   parsing to the XML toolset.  The use of XML also mitigates concerns
   over "network vs. host" byte ordering which is at the root of many
   network application bugs.

1.3. Relation to Existing Protocols

   The reformulations specified in this RFC follow as closely as
   possible the spirit of the RFCs on which they are based, and so MAY
   contain elements or attributes that would not be needed in a pure
   reworking (e.g. length attributes, which are implicit in XML.)

   The layering of network and transport protocols are maintained in
   this RFC despite the optimizations that could be made if the line
   were somewhat blurred (i.e. merging TCP and IP into a single, larger
   element in the DTD) in order to foster future use of this protocol as
   a basis for reformulating other protocols (such as ICMP.)

   Other than the encoding, the behavioral aspects of each of the
   existing protocols remain unchanged.  Routing, address spaces, TCP
   congestion control, etc. behave as specified in the extant standards.
   Adapting to new standards and experimental algorithm heuristics for
   improving performance will become much easier once the move to BLOAT
   has been completed.

1.4. Requirement Levels

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in BCP 14, RFC 2119
   [RFC2119].

2.   IPoXML

   This protocol MUST be implemented to be compliant with this RFC.
   IPoXML is the root protocol REQUIRED for effective use of TCPoXML
   (section 3.) and higher-level application protocols.

   The DTD for this document type can be found in section 7.1.

   The routing of IPoXML can be easily implemented on hosts with an XML
   parser, as the regular structure lends itself handily to parsing and
   validation of the document/datagram and then processing the
   destination address, TTL, and checksum before sending it on to its
   next-hop.

   The reformulation of IPv4 was chosen over IPv6 [RFC2460] due to the
   wider deployment of IPv4 and the fact that implementing IPv6 as XML
   would have exceeded the 1500 byte Ethernet MTU.



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   All BLOAT implementations MUST use - and specify - the UTF-8 encoding
   of RFC 2279 [RFC2279].  All BLOAT document/datagrams MUST be well-
   formed and include the XMLDecl.

2.1. IP Description

   A number of items have changed (for the better) from the original IP
   specification.  Bit-masks, where present have been converted into
   human-readable values.  IP addresses are listed in their dotted-
   decimal notation [RFC1123].  Length and checksum values are present
   as decimal integers.

   To calculate the length and checksum fields of the IP element, a
   canonicalized form of the element MUST be used.  The canonical form
   SHALL have no whitespace (including newline characters) between
   elements and only one space character between attributes.  There
   SHALL NOT be a space following the last attribute in an element.

   An iterative method SHOULD be used to calculate checksums, as the
   length field will vary based on the size of the checksum.

   The payload element bears special attention.  Due to the character
   set restrictions of XML, the payload of IP datagrams (which MAY
   contain arbitrary data) MUST be encoded for transport. This RFC
   REQUIRES the contents of the payload to be encoded in the base-64
   encoding of RFC 2045 [RFC2045], but removes the requirement that the
   encoded output MUST be wrapped on 76-character lines.
























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2.2. Example Datagram

   The following is an example IPoXML datagram with an empty payload:

   
   
   
   
3. TCPoXML This protocol MUST be implemented to be compliant with this RFC. The DTD for this document type can be found in section 7.2. 3.1. TCP Description A number of items have changed from the original TCP specification. Bit-masks, where present have been converted into human-readable values. Length and checksum and port values are present as decimal integers. To calculate the length and checksum fields of the TCP element, a canonicalized form of the element MUST be used as in section 2.1. An iterative method SHOULD be used to calculate checksums as in section 2.1. The payload element MUST be encoded as in section 2.1. Kennedy Informational [Page 4] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 The TCP offset element was expanded to a maximum of 255 from 16 to allow for the increased size of the header in XML. TCPoXML datagrams encapsulated by IPoXML MAY omit the header as well as the declaration. 3.2. Example Datagram The following is an example TCPoXML datagram with an empty payload: 4. UDPoXML This protocol MUST be implemented to be compliant with this RFC. The DTD for this document type can be found in section 7.3. 4.1. UDP Description A number of items have changed from the original UDP specification. Bit-masks, where present have been converted into human-readable values. Length and checksum and port values are present as decimal integers. Kennedy Informational [Page 5] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 To calculate the length and checksum fields of the UDP element, a canonicalized form of the element MUST be used as in section 2.1. An iterative method SHOULD be used to calculate checksums as in section 2.1. The payload element MUST be encoded as in section 2.1. UDPoXML datagrams encapsulated by IPoXML MAY omit the header as well as the declaration. 4.2. Example Datagram The following is an example UDPoXML datagram with an empty payload: 5. Network Transport This document provides for the transmission of BLOAT datagrams over two common families of physical layer transport. Future RFCs will address additional transports as routing vendors catch up to the specification, and we begin to see BLOAT routed across the Internet backbone. 5.1. Ethernet BLOAT is encapsulated in Ethernet datagrams as in [RFC894] with the exception that the type field of the Ethernet frame MUST contain the value 0xBEEF. The first 5 octets of the Ethernet frame payload will be 0x3c 3f 78 6d 6c (" --> Kennedy Informational [Page 7] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 Kennedy Informational [Page 9] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 Kennedy Informational [Page 10] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 7.2. TCPoXML DTD Kennedy Informational [Page 11] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 Kennedy Informational [Page 12] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 7.3. UDPoXML DTD Kennedy Informational [Page 13] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 8. Security Considerations XML, as a subset of SGML, has the same security considerations as specified in SGML Media Types [RFC1874]. Security considerations that apply to IP, TCP and UDP also likely apply to BLOAT as it does not attempt to correct for issues not related to message format. 9. References [JABBER] Miller, J., "Jabber", draft-miller-jabber-00.txt, February 2002. (Work in Progress) [RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, August 1980. [RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1981. [RFC793] Postel, J., "Transmission Control Protocol", STD 7, RFC 793, September 1981. [RFC894] Hornig, C., "Standard for the Transmission of IP Datagrams over Ethernet Networks.", RFC 894, April 1984. [RFC1042] Postel, J. and J. Reynolds, "Standard for the Transmission of IP Datagrams Over IEEE 802 Networks", STD 43, RFC 1042, February 1988. [RFC1123] Braden, R., "Requirements for Internet Hosts - Application and Support", RFC 1123, October 1989. [RFC1874] Levinson, E., "SGML Media Types", RFC 1874, December 1995. [RFC2003] Perkins, C., "IP Encapsulation within IP", RFC 2003, October 1996. [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies", RFC 2045, November 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2279] Yergeau, F., "UTF-8, a transformation format of ISO 10646", RFC 2279, January 1998. Kennedy Informational [Page 14] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", RFC 2460, December 1998. [RFC3080] Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC 3080, March 2001. [SOAP] Box, D., Ehnebuske, D., Kakivaya, G., Layman, A., Mendelsohn, N., Nielsen, H. F., Thatte, S. Winer, D., "Simple Object Access Protocol (SOAP) 1.1" World Wide Web Consortium Note, May 2000 http://www.w3.org/TR/SOAP/ [XML] Bray, T., Paoli, J., Sperberg-McQueen, C. M., "Extensible Markup Language (XML)" World Wide Web Consortium Recommendation REC- xml-19980210. http://www.w3.org/TR/1998/REC-xml-19980210 10. Author's Address Hugh Kennedy Mimezine 1060 West Addison Chicago, IL 60613 USA EMail: kennedyh@engin.umich.edu Kennedy Informational [Page 15] RFC 3252 Binary Lexical Octet Ad-hoc Transport 1 April 2002 11. Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Kennedy Informational [Page 16]