INTERNET-DRAFT M. Yevstifeyev
Intended Status: Experimental January 30, 2011
Expires: August 3, 2011
Extendable User Datagram Protocol (EUDP)
<draft-yevstifeyev-eudp-06>
Abstract
This document is a specification of experimental Extendable User
Datagram Protocol (EUDP), which is based on User Datagram Protocol
(UDP), but allows to extend its header and, therefore, its
functionality with options.
Status of this Memo
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document authors. All rights reserved.
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to this document. Code Components extracted from this document must
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Protocol Description . . . . . . . . . . . . . . . . . . . . . 4
2.1. Lower Layer Protocols Considerations . . . . . . . . . . . 4
2.2. Packet Format . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.1. Header . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2. Fields . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. EUDP Options . . . . . . . . . . . . . . . . . . . . . . . 5
2.3.1. Generic Description . . . . . . . . . . . . . . . . . 5
2.3.2. Pre-Defined Options . . . . . . . . . . . . . . . . . 5
2.3.2.1. 'No Operation' Option . . . . . . . . . . . . . . 5
2.3.2.2. 'End Of Options List' Option . . . . . . . . . . 6
2.3.2.3. 'Echo Request' Option . . . . . . . . . . . . . . 6
2.3.2.4. 'Echo Response' Option . . . . . . . . . . . . . 6
2.3.2.5. 'Packet Identifier' Option . . . . . . . . . . . 7
2.3.2.6. 'Packet Acknowledgment' Option . . . . . . . . . 7
2.4. Pseudo Header . . . . . . . . . . . . . . . . . . . . . . . 7
2.5. Packet Revival Acknowledgment Mechanism . . . . . . . . . . 7
2.6. Compatibility with UDP . . . . . . . . . . . . . . . . . . 8
3. Security Considerations . . . . . . . . . . . . . . . . . . . . 9
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
4.1. EUDP Options Numbers Registry . . . . . . . . . . . . . . 10
4.2. EUDP Ports Registry . . . . . . . . . . . . . . . . . . . 11
4.3. IP Protocol Number Assignment . . . . . . . . . . . . . . 11
5. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Normative References . . . . . . . . . . . . . . . . . . 11
5.2. Informative References . . . . . . . . . . . . . . . . . 11
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 11
Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
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1. Introduction
This document is a specification of experimental Extendable User
Datagram Protocol (EUDP), which is based on User Datagram Protocol
(UDP), but allows to extend its header and, therefore, its
functionality with options.
Such solution may be useful in the situations when UDP provides lack
of features while other transport-layer protocols, such as
Transmission Control Protocol (TCP) [RFC793] or Datagram Congestion
Control Protocol (DCCP) [RFC4340], have excessive facilities, which
might not be needed in such particular case. Current transport-layer
protocols are not able to cope with such situations. Unlike them,
EUDP may provide theoretically unlimited number of features, that may
be appended to core transport facilities, depending on what the
client wants EUDP to provide. Therefore, EUDP is intended to be a
universal solution, that may be used in almost any situation and may
suit to almost any requirements.
1.1. Terminology
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 RFC 2119 [RFC2119].
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2. Protocol Description
2.1. Lower Layer Protocols Considerations
EUDP is a transport-layer protocol. It is implemented on the top of
Internet Protocol (IP). EUDP supports as IPv4 [RFC791], as IPv6
[RFC2460] as lower-layer protocol. The IP Protocol number to be used
with EUDP is TBD1. Moreover, EUDP SHOULD be able to operate on the
any protocol that provides the same functionality as IP, such as EIP
[RFC1385] or TP/IX [RFC1475].
2.2. Packet Format
2.2.1. Header
The EUDP header is shown in the figure 1.
0 15 16 31
+----------------+----------------+
| Source Port |Destination Port|
+----------------+----------------+
| Data Offset | Reserved |
+----------------+----------------+
| |
: Options :
: |
| +----------------+
| | Padding |
+----------------+----------------+
| |
: Data :
| |
+----------------+----------------+
Figure 1
2.2.2. Fields
Source Port (16 bits) - REQUIRED field which is defied and is to be
used as described in UDP specification - RFC 768 [RFC768]. EUDP uses
the same port set as UDP.
Destination Port (16 bits) - REQUIRED field which is defied and is to
be used as described in UDP specification - RFC 768 [RFC768]. EUDP
uses the same port set as UDP.
Data Offset (16 bits) - REQUIRED field which is the number of 32 bit
words in the EUDP header. The EUDP header (even one including
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options) MUST be an integral number of 32 bits long.
Options (variable length) - OPIONAL field, that is used to carry EUDP
options in. EUDP option are described in Section 2.3.
Padding (variable length) - OPTIONAL field. The EUDP header padding
is used to ensure that the EUDP header ends and data begins on a 32
bit boundary. The padding MUST be composed of zeros.
NOTE: Bits 48-63 are reserved for future use and MUST be ignored by
EUDP hosts until their use will be properly specified.
2.3. EUDP Options
2.3.1. Generic Description
EUDP options are placed into the 'Options' header field. Options may
occupy space at the end of the EUDP header and are a multiple of 8
bits in length. An option may begin on any octet boundary. There
are two cases for the format of an option:
a) a single octet of option-kind.
b) an octet of option-kind, an octet of option-length, and the
actual option-data octets. The option-length counts the two octets
of option-kind and option-length as well as the option-data octets.
Note that the list of options MAY be shorter than the data offset
field might imply. The content of the header beyond the 'End Of
Options List' option MUST be header padding (i.e., zero).
All options can be _mandatory_ or _elective_ for support. EUDP nodes
MUST support all _mandatory_ options. Support of _elective_ options
is OPTIONAL.
Pre-defined options are specified in Section 2.3.2.
2.3.2. Pre-Defined Options
This section specifies pre-defined EUDP options.
2.3.2.1. 'No Operation' Option
+--------+
| Kind=0 |
+--------+
This option may be used between options, for example, to align the
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beginning of a subsequent option on a word boundary.
The option is _mandatory_ for support.
2.3.2.2. 'End Of Options List' Option
+--------+
| Kind=1 |
+--------+
This option code indicates the end of the option list. This might
not coincide with the end of the EUDP header according to the 'Data
Offset' header field. This SHALL be used at the end of all options,
not the end of each option, and need only be used if the end of the
options would not otherwise coincide with the end of the EUDP header.
The option is _mandatory_ for support.
2.3.2.3. 'Echo Request' Option
+--------+--------+-------//-------+
| Kind=2 | Length | Data |
+--------+--------+-------//-------+
The 'Echo Request' option is used to provide the possibility of echo
debugging using the EUDP. The option-data octets of option MAY
consist of arbitrary octets. The receiver of the packet with this
option MUST answer with the packet with 'Echo Response' option (see
Section 2.3.2.4).
The option is _elective_ for support.
2.3.2.4. 'Echo Response' Option
+--------+--------+-------//-------+
| Kind=3 | Length | Data |
+--------+--------+-------//-------+
The 'Echo Response' option is used to answer the packets with 'Echo
Request' option. The packet containing 'Echo Response' option MUST
be send after receiving any EUDP packet with 'Echo Request' option.
The option-data octets of the option MUST be the same as in 'Echo
Request' option in the received packet.
The option is _elective_ for support.
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2.3.2.5. 'Packet Identifier' Option
+--------+--------+--------+-------+
| Kind=4 |Length=4| Packet ID |
+--------+--------+--------+-------+
The 'Packet Identifier' option is asked to request the acknowledgment
of the single packet. The 'Packet ID' field is filled by arbitrary
bytes by the sender of the packet with this option. The receiver of
the packet with 'Packet Identifier' option MUST answer with the
packet with 'Packet Acknowledgment' option (see Section 2.3.2.6). See
Section 2.5 for details.
The option is _elective_ for support.
2.3.2.6. 'Packet Acknowledgment' Option
+--------+--------+--------+-------+
| Kind=5 |Length=4| ACK Packet ID |
+--------+--------+--------+-------+
The 'Packet Acknowledgment' option is used to answer the packets with
'Packet Identifier' option. The 'ACK Packet ID' field in the option
in the packet sent to the originating host for packet with 'Packet
Identifier' option MUST be the same as in received from this host
packet. See Section 2.5 for details.
The option is _elective_ for support.
2.3.2.7. 'Options Negotiation Request' Option
+--------+--------+--------+-------//-------+
| Kind=6 | Length | Opt.#1 | Opt#2 .. Opt#N |
+--------+--------+--------+-------//-------+
The 'Options Negotiation Request' option is used to initiate the
negotiation of use of _elective_ options (see Section 2.3.1). If the
EUDP host wants to use one or more _elective_ options, it SHOULD
firstly negotiate their use with the other host. The option-data
octets of the option contain the numbers of options the host wants to
negotiate. The EUDP host that receives the packet with this option
SHALL answer with the packet with 'Options Negotiation Response' (see
Section 2.3.2.8). The 'Options Negotiation Request' option MUST
contain the numbers of _elective_ options only.
The option is _mandatory_ for support.
2.3.2.8. 'Options Negotiation Response' Option
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+--------+--------+--------+-------//-------+
| Kind=7 | Length | Opt.#1 | Opt#2 .. Opt#N |
+--------+--------+--------+-------//-------+
The 'Options Negotiation Response' option is used to complete the
_elective_ options negotiation. Once EUDP host receives the 'Options
Negotiation Request' option (see Section 2.3.2.7), it SHALL check
what option from the list mentioned in the negotiation request it
supports and put appropriate values into the 'Options Negotiation
Response' option, put it into the EUDP packet and send back.
The option is _mandatory_ for support.
2.3.2.9. 'Packet Checksum' Option
+--------+--------+--------+-------+
| Kind=8 |Length=4| Checksum |
+--------+--------+--------+-------+
The 'Packet Checksum' option is used to carry packet checksum,
calculated using the method described in RFC 768 [RFC768]. Packets
containing this option with bad checksum SHOULD be discarded.
The option is _elective_ for support.
2.4. Pseudo Header
EUDP does not use pseudo header.
2.5. Packet Delivery Acknowledgment Mechanism
EUDP provides the possibility to request the acknowledgment of the
single EUDP packet. This is provided by 'Packet Identifier' and
'Packet Acknowledgment' options. In the simplest form, the delivery
acknowledgment mechanism works as below.
If EUDP host (let it be A) wants to request the acknowledgment of
delivery of some packet, it puts the 'Packet Identifier' option in it
and sends this packet to another EUDP host (let it be B). Once B
receives the A's packet, it checks the 'Packet Identifier' option to
find out the packet identifier. After it finds it out, this number
becomes the 'ACK Packet Identifier', that is put into 'Packet
Acknowledgment' option, which is put into the EUDP packet, and sent
to A. The packet identifiers MAY be reused once they are
acknowledged, since EUDP does provides stateless connection.
Compared with acknowledgment mechanism of TCP [RFC793], EUDP provides
simpler and more liberal system. While TCP makes using the packet
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sequence numbers and acknowledgement mandatory, EUDP allows the host
to decide whether the packet needs to be acknowledged by the other
side or not.
2.6. Compatibility with UDP
The applications which use UDP can safely use EUDP with no options
instead.
3. Security Considerations
Generic security issues for UDP concern EUDP as well.
Additional security can be provided by EUDP options. This document
does not define such options.
UDP itself does not provide any authentication features. Such
features can be provided by additional options, which are not defined
by this document.
4. IANA Considerations
4.1. 'EUDP Options Numbers' Registry
IANA is asked to create and maintain the registry named 'EUDP Options
Numbers Registry' following the guidelines below.
The regsitry consists of 5 values: Option Kind, Option Length,
Support Criteria, Name and Reference. They are described below.
Option Kind - an integer; refers to the value used in EUDP options.
Values from 0 to 255 are assigned.
Option Length - an integer, 'variable' (for multi-octet options) or
'N/A' (for one-octet options).
Support Criteria - 'Mandatory' and 'Elective' (see Section 2.3.1).
Name - contains the name of the option.
Reference - the reference to the document, that defines the option.
The initial values are given below; assignments to this registry for
_mandatory_ options are to be made following the 'IETF Consensus'
policies; for _elective_ options - following the 'RFC required'
policies. [RFC5226]
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+-------+-------+----------+------------------------------+-----------+
| # | Length| Support | Name | Reference |
+-------+-------+----------+------------------------------+-----------+
| 0 | N/A | mandatory| No Operation | RFC xxxx |
| 1 | N/A | mandatory| End Of Options List | RFC xxxx |
| 2 | var. | elective | Echo Request | RFC xxxx |
| 3 | var. | elective | Echo Response | RFC xxxx |
| 4 | 4 | elective | Packet Identifier | RFC xxxx |
| 5 | 4 | elective | Packet Acknowledgment | RFC xxxx |
| 6 | var. | mandatory| Options Negotiation Request | RFC xxxx |
| 7 | var. | mandatory| Options Negotiation Response | RFC xxxx |
| 8 | 4 | elective | Packet Checksum | RFC xxxx |
| 9-252 | -- | -- | Unassigned | RFC xxxx |
| 253 | -- | -- | Used for Experimentation | RFC xxxx |
| 254 | -- | -- | Used for Experimentation | RFC xxxx |
| 255 | -- | -- | Reserved | RFC xxxx |
+-------+-------+----------+------------------------------+-----------+
[RFC Editor: Please replace xxxx with assigned RFC number]
4.2. EUDP Port Numbers Assignment
As EUDP uses the same port set as UDP, IANA is asked to mark the UDP
port numbers registry values may be used with EUDP as well.
4.3. IP Protocol Number Assignment
IANA has assigned the IP protocol number TBD1 to be used with EUDP.
5. References
5.1. Normative References
[RFC768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.
[RFC791] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.
[RFC2119] S. Bradner, "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
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5.2. Informative References
[RFC793] Postel, J., "Transmission Control Protocol", STD 7, RFC
793, September 1981.
[RFC1385] Wang, Z., "EIP: The Extended Internet Protocol", RFC
1385, November 1992.
[RFC1475] Ullmann, R., "TP/IX: The Next Internet", RFC 1475, June
1993.
[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340, March
2006.
Appendix A. Acknowledgments
The portions of RFC 793 [RFC793], whose author - Jon Postel - is
acknowledged, are adopted in this document for describing options.
Author's Addresses
Mykyta Yevstifeyev
Kotovsk, Ukraine
EMail: evnikita2@gmail.com
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