RFC 5354 EXPERIMENTAL TRANSPORT · PROTOCOL REGISTRATION
Aggregate Server Access Protocol (ASAP) and Endpoint Handlespace Redundancy Protocol (ENRP) Parameters
Reference parameters for ASAP and ENRP protocols.
RFC EDITOR
Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate Server Access Protocol (ASAP) and Endpoint Handlespace Redundancy Protocol (ENRP) Parameters", RFC 5354, DOI 10.17487/RFC5354, September 2008, <https://www.rfc-editor.org/info/rfc5354>.
BIBTEX
@misc{rfc5354,
series = {Request for Comments},
number = 5354,
howpublished = {RFC 5354},
publisher = {RFC Editor},
doi = {10.17487/RFC5354},
url = {https://www.rfc-editor.org/info/rfc5354},
author = {R. Stewart and Q. Xie and M. Stillman and M. Tuexen},
title = {{Aggregate Server Access Protocol (ASAP) and Endpoint Handlespace Redundancy Protocol (ENRP) Parameters}},
pagetotal = 23,
year = 2008,
month = sep,
} RFC text
Contents
Network Working Group R. Stewart
Request for Comments: 5354 Q. Xie
Category: Experimental The Resource Group
M. Stillman
Nokia
M. Tuexen
Muenster Univ. of Applied Sciences
September 2008
Aggregate Server Access Protocol (ASAP) and
Endpoint Handlespace Redundancy Protocol (ENRP) Parameters
Status of This Memo
This memo defines an Experimental Protocol for the Internet
community. It does not specify an Internet standard of any kind.
Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.
Abstract
This document details the parameters of the Aggregate Server Access
Protocol (ASAP) and Endpoint Handlespace Redundancy Protocol (ENRP)
defined within the Reliable Server Pooling (RSerPool) architecture.
Table of Contents
1. Introduction ....................................................3
1.1. Conventions ................................................3
2. Parameters in General ...........................................3
3. ENRP-ASAP Common Parameters .....................................3
3.1. IPv4 Address Parameter .....................................6
3.2. IPv6 Address Parameter .....................................6
3.3. DCCP Transport Parameter ...................................7
3.4. SCTP Transport Parameter ...................................8
3.5. TCP Transport Parameter ....................................9
3.6. UDP Transport Parameter ....................................9
3.7. UDP-Lite Transport Parameter ..............................10
3.8. Pool Member Selection Policy Parameter ....................11
3.9. Pool Handle Parameter .....................................12
3.10. Pool Element Parameter ...................................12
3.11. Server Information Parameter .............................13
3.12. Operation Error Parameter ................................14
3.12.1. Unspecified Error .................................15
3.12.2. Unrecognized Parameter Error ......................15
3.12.3. Unrecognized Message Error ........................15
3.12.4. Invalid Values Error ..............................16
3.12.5. Non-Unique PE Identifier Error ....................16
3.12.6. Inconsistent Pool Policy Error ....................16
3.12.7. Lack of Resources Error ...........................16
3.12.8. Inconsistent Transport Type Error .................16
3.12.9. Inconsistent Data/Control Configuration Error .....16
3.12.10. Rejected Due to Security Considerations ..........16
3.12.11. Unknown Pool Handle Error ........................17
3.13. Cookie Parameter .........................................17
3.14. PE Identifier Parameter ..................................17
3.15. PE Checksum Parameter ....................................18
3.16. Opaque Transport Parameter ...............................18
4. Common Message Formats .........................................18
5. IANA Considerations ............................................20
5.1. A New Table for RSerPool Parameter Types ..................20
5.2. A New Table for RSerPool Error Causes .....................21
6. Security Considerations ........................................21
7. Normative References ...........................................21
1. Introduction
The Aggregate Server Access Protocol (ASAP) [RFC5352], in conjunction
with the Endpoint Handlespace Redundancy Protocol (ENRP) [RFC5353],
provides a high-availability, data-transfer mechanism over IP
networks.
Both protocols work together and so share many common parameters used
in message formats. This document details the common message
parameters shared between the two protocols. This document provides
parameter formats only; for procedures and message composition,
please refer to the respective [RFC5352] and [RFC5353] documents.
1.1. Conventions
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 [RFC2119].
2. Parameters in General
All parameters described below MUST be in network byte order (aka Big
Endian, i.e., the most significant byte first) during transmission.
Please note that messages in both ENRP and ASAP are often composed of
multiple parameters. These parameters may also be nested. In such a
case, a nested parameter will include the length of the padding
between the nested parameters but not the last padding.
3. ENRP-ASAP Common Parameters
Parameters are defined in the following Type-Length-Value (TLV)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Parameter Type | Parameter Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Parameter Value :
: +-------------------------------:
: | Padding :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Parameter Type: 16 bits (unsigned integer)
The Type field is a 16-bit identifier of the type of parameter.
It takes a value of 0 to 65534.
The value of 65535 is reserved for IETF-defined extensions.
Values, other than those defined in the specific ENRP parameter
description, are reserved by IETF. (Additional types, when
needed, will be defined in the future through appropriate IETF/
IANA procedures.)
The Parameter Types are encoded such that the two bits of the
highest-order specify the action that must be taken if the
processing endpoint does not recognize the Parameter Type.
00 Stop processing this ENRP or ASAP message and discard it; do
not process any further parameters within it.
01 Stop processing this ENRP or ASAP message and discard it; do
not process any further parameters within it, and report the
unrecognized parameter in an 'Unrecognized Parameter' error
(see Section 3.12).
10 Skip this parameter and continue processing.
11 Skip this parameter and continue processing, but report the
unrecognized parameter in an 'Unrecognized Parameter' error
(see Section 3.12).
The values of parameter types are defined as follows:
+-----------------+------------------------------+
| Value | Parameter Type |
+-----------------+------------------------------+
| 0x0 | (Reserved by IETF) |
| 0x1 | IPv4 Address |
| 0x2 | IPv6 Address |
| 0x3 | DCCP Transport |
| 0x4 | SCTP Transport |
| 0x5 | TCP Transport |
| 0x6 | UDP Transport |
| 0x7 | UDP-Lite |
| 0x8 | Pool Member Selection Policy |
| 0x9 | Pool Handle |
| 0xa | Pool Element |
| 0xb | Server Information |
| 0xc | Operation Error |
| 0xd | Cookie |
| 0xe | PE Identifier |
| 0xf | PE Checksum |
| 0x10 | Opaque Transport |
| 0x11-0xfffffffe | (Available for assignment) |
| 0xffffffff | IETF-defined extensions |
+-----------------+------------------------------+
Table 1
Parameter Length: 16 bits (unsigned integer)
The Parameter Length field contains the size of the parameter in
bytes, including the Parameter Type, Parameter Length, and
Parameter Value fields. Thus, a parameter with a zero-length
Parameter Value field would have a Length field of 4.
The total length of a parameter (including Type, Parameter Length
and Value fields) MUST be a multiple of 4 bytes. If the length of
the parameter is not a multiple of 4 bytes, the sender MUST pad
the parameter at the end (i.e., after the Parameter Value field)
with all zero bytes. The length of this padding is not included
in the Parameter Length field. A sender MUST NOT pad with more
than 3 bytes. The receiver MUST ignore the padding bytes.
Parameter Value: variable length.
The Parameter Value field contains the actual information to be
transferred in the parameter.
Parameter Padding: variable length.
The Parameter Padding, as described above.
3.1. IPv4 Address Parameter
This parameter defines a TLV that carries an IPv4 address.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x1 | Length = 0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv4 Address: 32 bits (unsigned integer)
Contains an IPv4 address. It is binary encoded.
3.2. IPv6 Address Parameter
This parameter defines a TLV that carries an IPv6 address.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x2 | Length = 0x14 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| IPv6 Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
IPv6 Address: 128 bits (unsigned integer)
Contains an IPv6 address. It is binary encoded.
3.3. DCCP Transport Parameter
This parameter defines a TLV that describes a user transport using
Datagram Congestion Control Protocol (DCCP).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x3 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DCCP Port | (reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DCCP Service Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, DCCP port, reserved fields, and IP
Address Parameter.
DCCP Port: 16 bits (unsigned integer)
The DCCP port number signed to this DCCP user transport.
DCCP Service Code: 32 bits (unsigned integer)
The DCCP service code signed to this DCCP user transport.
IPv4 or IPv6 Address
Indicates an IPv4 or IPv6 address parameter (as defined above in
Section 3.1 and Section 3.2) assigned to this DCCP user transport.
Unlike in an SCTP Transport parameter, only one IP address
parameter can be present in a DCCP Transport parameter.
Note: The DCCP Port MUST NOT be used for control information. For
this reason, no Transport Use field is provided. DCCP MUST always be
treated as a "Data Only" type transport use.
3.4. SCTP Transport Parameter
This parameter defines a TLV that describes a user transport using
Stream Control Transport Protocol (SCTP).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x4 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCTP Port | Transport Use |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address #1 :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: ... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address #n :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, SCTP port, reserved fields, and all IP
Address Parameters present.
SCTP Port: 16 bits (unsigned integer)
The SCTP port number signed to this SCTP user transport.
Transport Use: 16 bits (unsigned integer)
This field represents how the pool element intends this transport
address to be used. The field MUST be populated with one of the
following values:
+-------------------+--------+
| Type | Value |
+-------------------+--------+
| DATA ONLY | 0x0000 |
| DATA plus CONTROL | 0x0001 |
+-------------------+--------+
IPv4 or IPv6 Address #1 - #n
Each indicates an IPv4 or IPv6 address parameter (as defined above
in Section 3.1 and Section 3.2) assigned to this SCTP user
transport. An SCTP Transport parameter may have a mixed list of
IPv4 and IPv6 addresses and at least one IP address parameter MUST
be present in an SCTP Transport parameter.
3.5. TCP Transport Parameter
This parameter defines a TLV that describes a user transport using
TCP protocol.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x5 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TCP Port | (reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, TCP port, reserved fields, and IP
Address Parameter.
TCP Port: 16 bits (unsigned integer)
The TCP port number signed to this TCP user transport.
IPv4 or IPv6 Address
Indicates an IPv4 or IPv6 address parameter (as defined above in
Section 3.1 and Section 3.2) assigned to this TCP user transport.
Unlike in an SCTP Transport parameter, only one IP Address
parameter can be present in a TCP Transport parameter.
Note: The TCP Port MUST NOT be used for control information. For
this reason, no Transport Use field is provided. TCP MUST always be
treated as a "Data Only" type transport use.
3.6. UDP Transport Parameter
This parameter defines a TLV that describes a user transport using
UDP protocol.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x6 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP Port | (reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, UDP port, reserved fields, and IP
Address Parameter.
UDP Port: 16 bits (unsigned integer)
The UDP port number signed to this UDP user transport.
IPv4 or IPv6 Address
Indicates an IPv4 or IPv6 address parameter (as defined above in
Section 3.1 and Section 3.2) assigned to this UDP user transport.
Unlike in an SCTP Transport parameter, only one IP Address
parameter can be present in a UDP Transport parameter.
Note: The UDP Port MUST NOT be used for control information. For
this reason, no Transport Use field is provided. UDP MUST always be
treated as a "Data Only" type transport use.
3.7. UDP-Lite Transport Parameter
This parameter defines a TLV that describes a user transport using
UDP-Lite protocol.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x7 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| UDP-Lite Port | (reserved) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: IPv4 or IPv6 Address :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, UDP-Lite port, reserved fields, and IP
Address Parameter.
UDP Port: 16 bits (unsigned integer)
The UDP-Lite port number signed to this UDP-Lite user transport.
IPv4 or IPv6 Address
Indicates an IPv4 or IPv6 address parameter (as defined above in
Section 3.1 and Section 3.2) assigned to this UDP-Lite user
transport. Unlike in an SCTP Transport parameter, only one IP
address parameter can be present in a UDP-Lite transport
parameter.
Note: The UDP-Lite Port MUST NOT be used for control information.
For this reason, no Transport Use field is provided. UDP-Lite MUST
always be treated as a "Data Only" type transport use.
3.8. Pool Member Selection Policy Parameter
This parameter defines a pool member selection policy. RSerPool
supports multiple pool member selection policies and also allows the
definition of new selection policies in the future.
The enforcement rules and handling procedures of all the policies are
defined in [RFC5352].
All pool member selection policies, both present and future, MUST use
the following general parameter 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x8 | Length = variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Policy Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Policy-specific Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, Policy Type, and the Policy-specific
Data fields.
Note, the Length field value will NOT include any padding at the
end of the parameter.
Policy Type: 32 bits (unsigned integer)
Specifies the type of selection policy. The values are defined in
[RFC5356].
Policy-specific Data:
The structure and fields for each presently defined policy type
are described in detail in [RFC5356].
3.9. Pool Handle Parameter
This parameter holds a pool handle.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x9 | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Pool Handle :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, and Pool Handle string.
Note, the value in the Length field will NOT cover any padding at
the end of the parameter.
Pool Handle
Defined as a sequence of (Length - 4) bytes.
3.10. Pool Element Parameter
This parameter is used in multiple ENRP messages to represent an ASAP
endpoint (i.e., a Pool Element (PE) in a pool) and the associated
information, such as its transport address, selection policy, and
other operational or status information of the PE.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xa | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PE Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Home ENRP Server Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Registration Life |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: User Transport param :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Member Selection Policy param :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ASAP Transport param :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of octets,
including the Type, Length, PE Identifier, Registration Life, User
Transport, and Member Selection Policy parameters.
Note, the value in the Length field will NOT cover any padding at
the end of this Pool Element parameter.
PE Identifier: 32 bits (unsigned integer)
Uniquely identifies the PE in the pool. The PE picks its
identifier when it starts up.
Home ENRP Server Identifier: 32 bits (unsigned integer)
Indicates the current Home ENRP server of this PE. Set to all 0s
if the PE's Home ENRP server is undetermined.
Registration Life: 32 bits (signed integer)
Indicates the lifetime of the registration in number of seconds.
A value of -1 indicates infinite lifetime.
User Transport
This can be either an DCCP, SCTP, TCP, UDP, UDP-Lite, or Opaque
Transport parameter (see Section 3.3, Section 3.4, Section 3.5,
Section 3.6, Section 3.7, and Section 3.16). A PE MUST have one
and only one User Transport.
Member Selection Policy
Contains one of the defined member selection policy parameters
(see Section 3.8).
ASAP Transport
This indicates the ASAP transport address of the PE and MUST be an
SCTP type transport parameter (see Section 3.4).
3.11. Server Information Parameter
This parameter is used in ENRP to pass basic information of an ENRP
server.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xb | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Server ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Server Transport :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of bytes.
Note, the value in the Length field will NOT cover any padding at
the end of the parameter.
Server ID: 32 bits (unsigned integer)
This is the ID of the ENRP server, as defined in [RFC5353].
Server Transport:
This is an SCTP Transport Parameter, as defined in Section 3.4,
that contains the network access address(es), SCTP port number,
etc. of the ENRP server.
3.12. Operation Error Parameter
This parameter is used in both ENRP and ASAP for a message sender to
report an error(s) to a message receiver.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xc | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: one or more Error Causes :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of bytes.
Note, the value in the Length field will NOT cover any padding at
the end of the parameter.
Error causes are defined as variable-length parameters using the
following 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cause Code | Cause Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Cause-Specific Information :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Cause Code: 16 bits (unsigned integer)
Defines the type of error condition being reported.
+------------------+-----------------------------------------+
| Cause Code Value | Cause Code |
+------------------+-----------------------------------------+
| 0x0 | Unspecified Error |
| 0x1 | Unrecognized Parameter |
| 0x2 | Unrecognized Message |
| 0x3 | Invalid Values |
| 0x4 | Non-unique PE Identifier |
| 0x5 | Inconsistent Pooling Policy |
| 0x6 | Lack of Resources |
| 0x7 | Inconsistent Transport Type |
| 0x8 | Inconsistent Data/Control Configuration |
| 0x9 | Unknown Pool Handle |
| 0xa | Rejected due to security considerations |
| 0xb -0xffff | (Available for assignment) |
+------------------+-----------------------------------------+
Table 2
Cause Length: 16 bits (unsigned integer)
Set to the size of the parameter in bytes, including the Cause
Code, Cause Length, and Cause-Specific Information fields, but not
including any padding at the end of this error cause TLV.
Cause-specific Information: variable length
This field carries the details of the error condition.
The following subsections (Section 3.12.1 - Section 3.12.9) define
specific error causes.
3.12.1. Unspecified Error
This error cause is used to report an unspecified error by the
sender. There is no cause specific information.
3.12.2. Unrecognized Parameter Error
This error cause is used to report an unrecognized parameter. The
complete, unrecognized parameter TLV is included as cause-specific
information. If a message contains multiple unrecognized parameters,
multiple error causes are used.
3.12.3. Unrecognized Message Error
This error cause is used to report an unrecognized message. The
unrecognized message TLV is included as cause-specific information.
3.12.4. Invalid Values Error
This error cause is used to report one or more invalid values found
in a received parameter. The offending TLV that contains the invalid
value(s) is included as cause-specific information.
3.12.5. Non-Unique PE Identifier Error
This error cause is used by an ENRP server to indicate to a
registering PE that the PE Identifier it chooses has already been
used by another PE in the pool. There is no cause-specific
information.
3.12.6. Inconsistent Pool Policy Error
This error cause is used by an ENRP server to indicate to a
registering PE that the pool policy it chooses does not match the
overall policy of the pool. A Pool Member Selection Policy TLV (see
Section 3.8) that indicates the overall pool policy is included as
cause-specific information.
3.12.7. Lack of Resources Error
This error cause is used to indicate that the sender does not have
certain resources to perform a requested function. There is no cause
specific information.
3.12.8. Inconsistent Transport Type Error
This error cause is used by an ENRP server to indicate to a
registering PE that the User Transport it chooses does not match the
overall user transport of the pool. A Transport TLV that indicates
the overall pool user transport type is included as cause-specific
information.
3.12.9. Inconsistent Data/Control Configuration Error
This error cause is used by an ENRP server to indicate to a
registering PE that the Transport Use field in the User Transport it
sent in its registration is inconsistent to the pool's overall data/
control channel configuration. There is no cause-specific
information.
3.12.10. Rejected Due to Security Considerations
This error cause is used by any endpoint to indicate a rejection of a
request due to a failure in security credentials or authorizations.
3.12.11. Unknown Pool Handle Error
This error cause is used by an ENRP server to indicate to a PE or PU
that the requested pool is unknown by the server. There is no cause-
specific information.
3.13. Cookie Parameter
This parameter defines a TLV that carries a Cookie.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xd | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Cookie :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of bytes,
including the Type, Length, and Cookie.
Cookie: variable length
The Cookie is an arbitrary byte string of (Length - 4) bytes.
3.14. PE Identifier Parameter
This parameter defines a TLV that carries a PE Identifier.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xe | Length=0x8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PE Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PE Identifier: 32 bits (unsigned integer)
Uniquely identifies the PE in the pool. The PE picks its
identifier when it starts up. See [RFC5352] for recommendations
on PE identifier generation.
3.15. PE Checksum Parameter
This parameter defines a TLV that carries a PE Checksum.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0xf | Length=0x6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PE Checksum | Padding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
PE Checksum: 16 bits (unsigned integer)
An overall checksum of all PEs in the current handlespace owned by
an ENRP server (which is normally the sender of this TLV). The
definition and calculation of this checksum is defined in
[RFC5353].
3.16. Opaque Transport Parameter
This parameter defines a TLV that carries opaque transport
information.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x10 | Length=variable |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Opaque Transport Data :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Length: 16 bits (unsigned integer)
Indicates the entire length of the parameter in number of bytes,
including the Type, Length, and Opaque Transport Data.
Opaque Transport Data: variable length
The Opaque Transport Data is an arbitrary byte string of (Length -
4) bytes.
4. Common Message Formats
The figure below illustrates the common format for all ASAP and ENRP
messages. Each message is formatted with a Message Type field, a
message-specific Flag field, a Message Length field, and a Value
field.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Message Type | Msg Flags | Message Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: :
: Message Value :
: :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Message Type: 8 bits (unsigned integer)
This field identifies the type of information contained in the
Message Value field. It takes a value from 0 to 254. The value
of 255 is reserved for future use as an extension field.
Message Types are encoded such that the two bits of the highest
order specify the action that must be taken if the message
receiver does not recognize the Message Type.
00 Stop processing this message and discard it.
01 Stop processing this message and discard it, and report the
unrecognized message in an 'Unrecognized Message' error (see
Section 3.12.3).
10 Reserved.
11 Reserved.
Message Flags: 8 bits
The usage of these bits depends on the message type, as given by
the Message Type. Unless otherwise specified, they are set to
zero on transmit and ignored on receipt.
Message Length: 16 bits (unsigned integer)
This value represents the size of the message in bytes, including
the Message Type, Message Flags, Message Length, and Message Value
fields. Therefore, if the Message Value field is zero length, the
Length field will be set to 4.
Note, the value in the Message Length field will NOT cover any
padding at the end of this message.
Message Value: variable length
The Message Value field contains the actual information to be
transferred in the message. The usage and format of this field is
dependent on the Message Type.
The total length of a message (including Type, Length, and Value
fields) MUST be a multiple of 4 bytes. If the length of the
message is not a multiple of 4 bytes, the sender MUST pad the
message with all zero bytes and this padding is not included in
the Message Length field. The sender should never pad with more
than 3 bytes. The receiver MUST ignore the padding bytes.
5. IANA Considerations
This document (RFC 5354) is the reference for all registrations
described in this section. All registrations have been listed on the
RSerPool Parameters page.
5.1. A New Table for RSerPool Parameter Types
RSerPool Parameter Types are maintained by IANA. Thirteen initial
values have been assigned by IANA, as described in Table 1. IANA
created a new table, "RSerPool Parameter Types":
+------------+------------------------------+
| Value | Parameter Type |
+------------+------------------------------+
| 0x0 | (Reserved by IETF) |
| 0x1 | IPv4 Address |
| 0x2 | IPv6 Address |
| 0x3 | DCCP Transport |
| 0x4 | SCTP Transport |
| 0x5 | TCP Transport |
| 0x6 | UDP Transport |
| 0x7 | UDP-Lite |
| 0x8 | Pool Member Selection Policy |
| 0x9 | Pool Handle |
| 0xa | Pool Element |
| 0xb | Server Information |
| 0xc | Operation Error |
| 0xd | Cookie |
| 0xe | PE Identifier |
| 0xf | PE Checksum |
| 0x10 | Opaque Transport |
| 0xffffffff | IETF-defined extensions |
| others | (Reserved by IETF) |
+------------+------------------------------+
Requests to register an RSerPool Parameter Type in this table should
be sent to IANA. The number must be unique. The "Specification
Required" policy of [RFC5226] MUST be applied.
5.2. A New Table for RSerPool Error Causes
RSerPool Error Causes are maintained by IANA. Eleven initial values
have been assigned by IANA, as described in Table 2. IANA created a
new table, "RSerPool Error Causes":
+------------------+-----------------------------------------+
| Cause Code Value | Cause Code |
+------------------+-----------------------------------------+
| 0x0 | Unspecified Error |
| 0x1 | Unrecognized Parameter |
| 0x2 | Unrecognized Message |
| 0x3 | Invalid Values |
| 0x4 | Non-Unique PE Identifier |
| 0x5 | Inconsistent Pooling Policy |
| 0x6 | Lack of Resources |
| 0x7 | Inconsistent Transport Type |
| 0x8 | Inconsistent Data/Control Configuration |
| 0x9 | Unknown Pool Handle |
| 0xa | Rejected Due to Security Considerations |
| others | (Reserved by IETF) |
+------------------+-----------------------------------------+
Requests to register an RSerPool Error Cause in this table should be
sent to IANA. The number must be unique. The "Specification
Required" policy of [RFC5226] MUST be applied.
6. Security Considerations
This document contains common parameter formats only. As such, it
specifies no new security constraints on either ENRP or ASAP.
Details on ENRP and ASAP security constraints are addressed in
[RFC5353] and [RFC5352].
7. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5352] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
"Aggregate Server Access Protocol (ASAP)", RFC 5352,
September 2008.
[RFC5353] Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A.
Silverton, "Endpoint Handlespace Redundancy Protocol
(ENRP)", RFC 5353, September 2008.
[RFC5356] Dreibholz, T. and M. Tuexen, "Reliable Server Pooling
Policies", RFC 5356, September 2008.
Authors' Addresses
Randall R. Stewart
The Resource Group
1700 Pennsylvania Ave NW
Suite 560
Washington, DC 20006
USA
Phone:
EMail: randall.stewart@trgworld.com
Qiaobing Xie
The Resource Group
1700 Pennsylvania Ave NW
Suite 560
Washington, D.C., 20006
USA
Phone: +1 224-465-5954
EMail: Qiaobing.Xie@gmail.com
Maureen Stillman
Nokia
1167 Peachtree Ct.
Naperville, IL 60540
USA
EMail: maureen.stillman@nokia.com
Michael Tuexen
Muenster Univ. of Applied Sciences
Stegerwaldstr. 39
48565 Steinfurt
Germany
EMail: tuexen@fh-muenster.de
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This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
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AI ELI5
On this page
PROBLEMASAP and ENRP protocols need to communicate consistently across different implementations. They require a shared set of parameter types, transport protocols, and error codes.
MECHANISMThis RFC defines and registers all the Type-Length-Value parameters and error causes used by ASAP and ENRP. It collects 16 parameter types covering addresses, transports, and policies, plus 11 error codes.
ENSURES INTEROPERABILITYImplementations can follow this registry to ensure compatible message exchange. This is part of the Reliable Server Pooling architecture for high-availability services.
§1Introduction
ASAP (Aggregate Server Access Protocol) and ENRP (Endpoint Handlespace Redundancy Protocol) are two companion protocols that work together to provide a high-availability, data-transfer mechanism over IP networks. They share many common parameters in their message formats.
This RFC is a reference document that details all the common message parameters shared between the two protocols. It provides parameter formats only; for how to use them, refer to RFC 5352 (ASAP) and RFC 5353 (ENRP). All parameters are transmitted in network byte order (big-endian).
Two protocols need to talk to each other using agreed-upon codes and message layouts. This document lists all those codes and layouts so they can communicate correctly.
§2Parameter and Message Structure
All parameters use a Type-Length-Value (TLV) format. Each parameter starts with a 16-bit type field (identifying what kind of data it is), followed by a 16-bit length field (how many bytes it contains), then the actual data, padded to align on 4-byte boundaries.
The parameter type field uses its two highest bits to specify how to handle unrecognized parameters: stop and discard, stop and report an error, skip and continue, or skip and report an error. This allows future extensions without breaking old implementations.
Messages themselves follow a similar structure: an 8-bit message type, 8-bit flags, 16-bit length, and a variable-length message value. Messages are also padded to 4-byte alignment.
Data is packaged like a labeled box: the label says what's inside, a number says how big it is, and then comes the data. Extra space is padded so everything lines up neatly.
| Field | Name | Size | Value | Description |
|---|---|---|---|---|
TYPE | Parameter Type | 2 bytes | Identifies the parameter type; the two highest bits control unrecognized handling. | |
LENGTH | Parameter Length | 2 bytes | Total length including Type, Length, Value and padding. | |
VALUE | Parameter Value | 2 bytes | Variable-length data; padded to 4-byte alignment. |
- 00Stop, discard — Stop processing and discard the message.
- 01Stop and report — Stop and send an error about the unrecognized parameter.
- 10Skip — Skip this parameter and continue processing.
- 11Skip and report — Skip and report an error about the unrecognized parameter.
§3Address and Transport Parameters
The RFC defines six transport protocol parameters: DCCP, SCTP, TCP, UDP, and UDP-Lite. Each carries a port number and one or more IP addresses. SCTP is special because it can list multiple addresses; the others support one IP address each.
Additionally, IPv4 and IPv6 Address parameters carry individual network addresses in binary form. IPv4 addresses are 32 bits; IPv6 addresses are 128 bits.
SCTP and ASAP transport parameters include a Transport Use field indicating whether the transport is for data only or for both data and control messages. Other transports are always data-only.
To send data to another computer, you need to know where it is (its address) and which door to knock on (its port). These parameters describe addresses and ports for different types of network pipes.
§4Pool Policies and Server Information
The RFC defines a Pool Member Selection Policy parameter that specifies which server in a pool should be chosen when a client asks for service. The actual policy types are defined in RFC 5356 and include round-robin, weighted round-robin, random, priority-based, and load-based policies.
A Pool Handle parameter names a pool (a group of servers), and a Pool Element parameter describes one server, including its ID, registration lifetime, user transport, selection policy, and ASAP control transport. The Server Information parameter describes an ENRP server itself, holding its ID and transport address.
When you need a cashier, the store has rules for which cashier serves you: maybe they take turns (round-robin) or you pick randomly. Pool parameters describe these rules and which servers belong to which group.
§5Error Reporting
The RFC defines an Operation Error parameter for reporting problems. It carries one or more error causes, each with a 16-bit cause code and detailed information. Eleven error causes are registered: unspecified error, unrecognized parameter, unrecognized message, invalid values, non-unique pool element identifier, inconsistent pool policy, lack of resources, inconsistent transport type, inconsistent data/control configuration, rejection due to security, and unknown pool handle.
Additional support parameters include a Cookie parameter (opaque state), a PE Identifier parameter (unique server ID), a PE Checksum parameter (integrity check over pool elements), and an Opaque Transport parameter (application-specific data).
When something goes wrong, the protocol sends an error message saying what happened. These are the standard error messages both protocols understand.
§6References
[RFC5352]RFC 5352Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate Server Access Protocol (ASAP)", RFC 5352, September 2008.September 2008[RFC5353]RFC 5353Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A. Silverton, "Endpoint Handlespace Redundancy Protocol (ENRP)", RFC 5353, September 2008.September 2008[RFC5356]RFC 5356Dreibholz, T. and M. Tuexen, "Reliable Server Pooling Policies", RFC 5356, September 2008.September 2008[RFC2119]RFC 2119Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.March 1997