Internet Engineering Task Force (IETF) M. Eisler

Internet Engineering Task Force (IETF) M. Eisler
Request for Comments: 5665 NetApp
Updates: 1833 January 2010
Category: Standards Track
ISSN: 2070-1721

IANA Considerations for Remote Procedure Call (RPC)
Network Identifiers and Universal Address Formats

Abstract

This document lists IANA Considerations for Remote Procedure Call
(RPC) Network Identifiers (netids) and RPC Universal Network
Addresses (uaddrs). This document updates, but does not replace, RFC
1833.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5665.

Copyright Notice

Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.

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RFC 5665 RPC Netids January 2010

Table of Contents

1. Introduction and Motivation .....................................3
2. Requirements Language ...........................................3
3. Considerations for the Netid of the Stream Control
Transmission Protocol ...........................................3
4. Security Considerations .........................................3
5. IANA Considerations .............................................3
5.1. IANA Considerations for Netids .............................4
5.1.1. Initial Registry ....................................6
5.1.2. Updating Registrations ..............................8
5.2. IANA Considerations for Uaddr Formats ......................8
5.2.1. Initial Registry ....................................9
5.2.2. Updating Registrations .............................10
5.2.3. Uaddr Formats ......................................10
5.2.3.1. Uaddr Format for System V Release
4 Loopback Transports .....................10
5.2.3.2. Uaddr Format for Netid "-" ................10
5.2.3.3. Uaddr Format for Most IPv4 Transports .....11
5.2.3.4. Uaddr Format for Most IPv6 Transports .....11
5.2.3.5. Uaddr Format for ICMP over IPv4 and IPv6 ..11
5.3. Cross Referencing between the Netid and Format Registry ...12
5.4. Port Assignment for NFS over SCTP .........................12
6. References .....................................................12
6.1. Normative References ......................................12
6.2. Informative References ....................................12
Appendix A. Acknowledgments ......................................14

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RFC 5665 RPC Netids January 2010

1. Introduction and Motivation

The concepts of an RPC (defined in RFC 5531 [4]) Network Identifier
(netid) and an RPC Universal Address (uaddr) were introduced in RFC
1833 [1] for distinguishing network addresses of multiple protocols
and representing those addresses in a canonical form. RFC 1833
states that a netid "is defined by a system administrator based on
local conventions, and cannot be depended on to have the same value
on every system". (The netid is contained in the field r_netid of
the data type rpcb_entry, and the uaddr is contained in the field
r_addr of the same data type, where rpcb_entry is defined in RFC
1833.) Since the publication of RFC 1833, it has been found that
protocols like Network File System version 4 (NFSv4.0) [5] and RPC/
RDMA (Remote Direct Memory Access) [6] depend on consistent values of
netids and representations of uaddrs. Current practices tend to
ensure this consistency. Thus, this document identifies the
considerations for IANA to establish registries of netids and uaddr
formats for RPC and specifies the initial content of the two
registries.

2. Requirements Language

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 [2].

3. Considerations for the Netid of the Stream Control Transmission
Protocol

The Stream Control Transmission Protocol (SCTP) (described in RFC
4960 [7]) is a connection-oriented protocol that supports both byte-
streamed and record-oriented data transfer. When the "sctp" and
"sctp6" netids are used, the Open Network Computing (ONC) RPC Record
Marking standard (see Section 11 of RFC 5531 [4]) is not used;
instead, SCTP's native record-oriented data transfer is used.

4. Security Considerations

Since this document is only concerned with the IANA management of the
Network Identifier (netid) and Universal Network Addresses (uaddrs)
format registry, it raises no new security issues.

5. IANA Considerations

This section uses terms that are defined in RFC 5226 [8].

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RFC 5665 RPC Netids January 2010

5.1. IANA Considerations for Netids

IANA has created a registry called "ONC RPC Netids". The remainder
of this section describes the registry.

All assignments to the ONC RPC Netids registry are made on one of two
bases:

o A First Come First Served basis subregistry per Section 4.1 of RFC
5226.

o A Standards Action basis subregistry per Section 4.1 of RFC 5226.

The eXternal Data Representation (XDR) encoding allows netids to be
up to 2^32 - 1 octets in length, but the registry will only allow a
much shorter length. Assignments made on a Standards Action basis
should be assigned netids 1 to 8 octets long. Assignments made on a
First Come First Served basis should be assigned netids 9 to 128
octets long. Some exceptions are listed in Table 2.

Some portion of the netid name space is Reserved:

o All netids, regardless of length, that start with the prefixes
"STDS" or "FCFS" are Reserved, in order to extend the name space
of either Standards Action or First Come First Served bases.

o To give the IESG the flexibility in the future to permit Private
and Experimental Uses, all netids with the prefixes "PRIV" or
"EXPE" are Reserved.

o To prevent confusion with the control protocol by the same name
[9], netids with the prefix "ICMP" are Reserved.

o Since netids are not constructed in an explicit hierarchical
manner, this document does not provide for Hierarchical Allocation
of netids. Nonetheless, all netids containing the octet "." are
Reserved for future possible provision of Hierarchical Allocation.

o The zero length netid is Reserved.

A recommended convention for netids corresponding to transports that
work over the IPv6 protocol is to have "6" as the last character in
the netid's name.

There are two subregistries of netids: one for Standards Action
assignments and one for First Come First Served assignments. Each
registry of netids is a list of assignments, each containing five
fields for each assignment.

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RFC 5665 RPC Netids January 2010

1. A US-ASCII string name that is the actual netid. The netid
should be 1 to 8 octets long for the Standards Action
subregistry, and 9 to 128 octets long for the First Come First
Served subregistry. The netid MUST NOT conflict with any other
registered netid. Despite the fact that netids are case
sensitive, the netid, when mapped to all upper case, MUST NOT
conflict with the value of any other registered netid after the
registered netid is mapped to upper case. In addition, when
mapped to upper case, the prefix of the netid MUST NOT be equal
to a Reserved prefix.

2. A constant name that can be used for software programs that wish
to use the transport protocol associated with the netid. The
name of the constant typically has the prefix "NC_", and a suffix
equal to the upper-case version of the netid. This constant name
should be a constant that is valid in the 'C' programming
language. This constant name MUST NOT conflict with any other
netid constant name. Constant names with the prefix "NC_STDS",
"NC_FCFS", "NC_PRIV", "NC_EXPE", and "NC_ICMP" are Reserved.
Constant names with a prefix of "NC_" and a total length of 11
characters or less should be for assignments made on the
Standards Action basis. The constant "NC_" is Reserved. The
constant name can be 1 to 131 octets long.

Given the typical derivation of the constant name from the netid,
the registration of the constant might be considered redundant.
This is not always true. For example, a netid might use a
character that is not valid in the programming language. The
first entry of Table 1 provides such an example.

3. A description and/or a reference to a description of how the
netid will be used. For assignments made on a First Come First
Served basis, the description should include, if applicable, a
reference to the transport and network protocols corresponding to
the netid. For assignments made on a Standards Action basis, the
description field must include the RFC numbers of the protocol
associated with the netid, including, if applicable, RFC numbers
of the transport and network protocols.

4. A point of contact of the registrant. For assignments made on a
First Come First Served basis:

* the point of contact should include an email address.

* subject to authorization by a Designated Expert, the point of
contact may be omitted for extraordinary situations, such as
the registration of a commonly used netid where the owner is
unknown.

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RFC 5665 RPC Netids January 2010

For assignments made on a Standards Action basis, the point of
contact is always determined by IESG.

5. A numerical value, used to cross reference the netid assignment
with an assignment in the uaddr format registry (see
Section 5.2). If the registrant is registering a netid that
cross references an existing assignment in the uaddr format
registry, then the registrant provides the actual value of the
cross reference along with the date the registrant retrieved the
cross reference value from the uaddr format registry. If the
registrant is registering both a new netid and new uaddr format,
then the registrant provides a value of TBD1 in the netid
request, and uses TBD1 in the uaddr format request. IANA will
then substitute TBD1 for the cross reference number IANA
allocates. Note that if a document requests multiple netid and
uaddr assignments, each additional uaddr format cross reference
will be identified as TBD2, TBD3, ..., etc.

5.1.1. Initial Registry

The initial list of netids is broken into two subregistries: those
assigned on a First Come First Served basis in Table 1 and those
assigned on a Standards Action basis in Table 2. These lists will
change as IANA registers additional netids as needed, and the
authoritative list of registered netids will always live with IANA.

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RFC 5665 RPC Netids January 2010

+-------------+--------------+---------------------------+-----+----+
| Netid | Constant | Description and/or | PoC | CR |
| | Name | Reference | | |
+-------------+--------------+---------------------------+-----+----+
| "-" | NC_NOPROTO | RFC1833 [1], | | 1 |
| | | Section 5.2.3.2 of RFC | | |
| | | 5665 | | |
| "ticlts" | NC_TICLTS | The loop back | | 0 |
| | | connectionless transport | | |
| | | used in System V Release | | |
| | | 4 and other operating | | |
| | | systems. Although this | | |
| | | assignment is made on a | | |
| | | First Come First Served | | |
| | | basis and is fewer than | | |
| | | nine characters long, the | | |
| | | exception is authorized. | | |
| | | See [10]. | | |
| "ticots" | NC_TICOTS | The loop back | | 0 |
| | | connection-oriented | | |
| | | transport used in System | | |
| | | V Release 4 and other | | |
| | | operating systems. See | | |
| | | [10]. Although this | | |
| | | assignment is made on a | | |
| | | First Come First Served | | |
| | | basis and is fewer than | | |
| | | nine characters long, the | | |
| | | exception is authorized. | | |
| "ticotsord" | NC_TICOTSORD | The loop back | | 0 |
| | | connection-oriented with | | |
| | | orderly-release transport | | |
| | | used in System V Release | | |
| | | 4 and other operating | | |
| | | systems. See [10]. | | |
+-------------+--------------+---------------------------+-----+----+

Table 1: Initial First Come First Served Netid Assignments

PoC: Point of Contact.

CR: Cross Reference to the Uaddr Format Registry.

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+---------+----------+----------------------------------+------+----+
| Netid | Constant | RFC(s) and Description (if | PoC | CR |
| | Name | needed) | | |
+---------+----------+----------------------------------+------+----+
| "rdma" | NC_RDMA | RFC 5666 [6], RFC 791 [11] | IESG | 2 |
| "rdma6" | NC_RDMA6 | RFC 5666 [6], RFC 2460 [12] | IESG | 3 |
| "sctp" | NC_SCTP | RFC 4960 [7], RFC 791 [11], | IESG | 2 |
| | | Section 3 of RFC 5665 | | |
| "sctp6" | NC_SCTP6 | RFC 4960 [7], RFC 2460 [12], | IESG | 3 |
| | | Section 3 of RFC 5665 | | |
| "tcp" | NC_TCP | RFC 793 [13], RFC 791 [11], | IESG | 2 |
| | | Section 11 of RFC 5531 [4] | | |
| "tcp6" | NC_TCP6 | RFC 793 [13], RFC 2460 [12], | IESG | 3 |
| | | Section 11 of RFC 5531 [4] | | |
| "udp" | NC_UDP | RFC 768 [14], RFC 791 [11] | IESG | 2 |
| "udp6" | NC_UDP6 | RFC 768 [14], RFC 2460 [12] | IESG | 3 |
+---------+----------+----------------------------------+------+----+

Table 2: Initial Standards Action Netid Assignments

5.1.2. Updating Registrations

Per Section 5.2 of RFC 5226, the registrant is always permitted to
update a registration made on a First Come First Served basis
"subject to the same constraints and review as with new
registrations". The IESG or a Designated Expert is permitted to
update any registration made on a First Come First Served basis,
which normally is done when the PoC cannot be reached in order to
make necessary updates. Examples where an update would be needed
include, but are not limited to: the email address or other contact
information becomes invalid; the reference to the corresponding
protocol becomes obsolete or unavailable; RFC 1833 is updated or
replaced in such a way that the scope of netids changes, requiring
additional fields in the assignment.

Only the IESG, on the advice of a Designated Expert, can update a
registration made on a Standards Action basis.

5.2. IANA Considerations for Uaddr Formats

IANA has created a registry called "ONC RPC Uaddr Format Registry"
(called the "format registry" for the remainder of this document).
The remainder of this section describes the registry.

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All assignments to the format registry are made on one of two bases:

o First Come First Served basis per Section 4.1 of RFC 5226.

o Standards Action per Section 4.1 of RFC 5226.

The registry of formats is a list of assignments, each containing
four fields for each assignment.

1. The basis for the assignment, which can be either FCFS for First
Come First Served assignments or STDS for Standards Action
assignments.

2. A description and/or reference to a description of the actual
uaddr format. Assignments made on a Standards Action basis
always have a reference to an RFC.

3. For assignments made on a First Come First Served basis, a point
of contact, including an email address. Subject to authorization
by a Designated Expert, the point of contact may be omitted for
extraordinary situations, such as the registration of a commonly
used format where the owner is unknown. For assignments made on
a Standards Action basis, the point of contact is always
determined by the IESG.

4. A numerical value, used to cross reference the format assignment
with an assignment in the netid registry. The registrant
provides a value of TBD1 for the cross reference field when
requesting an assignment. IANA will assign TBD1 to a real value.
Note that if a document requests multiple uaddr assignments, each
additional uaddr format cross reference will be identified as
TBD2, TBD3, ..., etc.

All requests for assignments to the format registry on a Standards
Action basis are only for Standards Track RFCs approved by the IESG.

5.2.1. Initial Registry

The initial list of formats is in Table 3. This list will change as
IANA registers additional formats as needed, and the authoritative
list of registered formats will always live with IANA.

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+-------+-----------------------------------------------+------+----+
| Basis | Description and/or Reference | PoC | CR |
+-------+-----------------------------------------------+------+----+
| FCFS | System V Release 4 loopback transport uaddr | | 0 |
| | format. Section 5.2.3.1 of RFC 5665 | | |
| FCFS | Uaddr format for NC_NOPROTO. Section 5.2.3.2 | | 1 |
| | of RFC 5665 | | |
| STDS | Uaddr format for IPv4 transports. | IESG | 2 |
| | Section 5.2.3.3 of RFC 5665 | | |
| STDS | Uaddr format for IPv6 transports. | IESG | 3 |
| | Section 5.2.3.4 of RFC 5665 | | |
+-------+-----------------------------------------------+------+----+

Table 3: Initial Format Assignments

5.2.2. Updating Registrations

The registrant is always permitted to update a registration made on a
First Come First Served basis "subject to the same constraints and
review as with new registrations." The IESG is permitted to update
any registration made on a First Come First Served basis, which
normally is done when the PoC cannot be reached in order to make
necessary updates. Examples where an update would be needed include,
but are not limited to: the email address or other contact
information becomes invalid; the reference to the format description
becomes obsolete or unavailable; RFC 1833 is updated or replaced in
such a way that the scope of uaddr formats changes, requiring
additional fields in the assignment.

Only the IESG, on the advice of a Designated Expert, can update a
registration made on a Standards Action basis.

5.2.3. Uaddr Formats

5.2.3.1. Uaddr Format for System V Release 4 Loopback Transports

Although RFC 1833 specifies the uaddr as the XDR data type string
(hence, limited to US-ASCII), implementations of the System V Release
4 loopback transports will use an opaque string of octets. Thus, the
format of a loopback transport address is any non-zero length array
of octets.

5.2.3.2. Uaddr Format for Netid "-"

There is no address format for netid "-". This netid is apparently
for internal use for supporting some implementations of RFC 1833.

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RFC 5665 RPC Netids January 2010

5.2.3.3. Uaddr Format for Most IPv4 Transports

Most transport protocols that operate over IPv4 use 16-bit port
numbers, including RDMA [6], SCTP [7], TCP [13], and UDP [14]. The
format of the uaddr for the above 16-bit port transports (when used
over IPv4) is the US-ASCII string:

h1.h2.h3.h4.p1.p2

The prefix "h1.h2.h3.h4" is the standard textual form for
representing an IPv4 address, which is always four octets long.
Assuming big-endian ordering, h1, h2, h3, and h4 are, respectively,
the first through fourth octets each converted to ASCII-decimal. The
suffix "p1.p2" is a textual form for representing a service port.
Assuming big-endian ordering, p1 and p2 are, respectively, the first
and second octets each converted to ASCII-decimal. For example, if a
host, in big-endian order, has an address in hexadecimal of
0xC0000207 and there is a service listening on, in big-endian order,
port 0xCB51 (decimal 52049), then the complete uaddr is
"192.0.2.7.203.81".

5.2.3.4. Uaddr Format for Most IPv6 Transports

Most transport protocols that operate over IPv6 use 16-bit port
numbers, including RDMA [6], SCTP [7], TCP [13], and UDP [14]. The
format of the uaddr for the above 16-bit port transports (when used
over IPv6) is the US-ASCII string:

x1:x2:x3:x4:x5:x6:x7:x8.p1.p2

The suffix "p1.p2" is the service port, and is computed the same way
as with uaddrs for transports over IPv4 (see Section 5.2.3.3). The
prefix "x1:x2:x3:x4:x5:x6:x7:x8" is the preferred textual form for
representing an IPv6 address as defined in Section 2.2 of RFC 4291
[3]. Additionally, the two alternative forms specified in Section
2.2 of RFC 4291 are also acceptable.

5.2.3.5. Uaddr Format for ICMP over IPv4 and IPv6

As ICMP is not a true transport, there is no uaddr format for ICMP.
The netid assignments "icmp" and "icmp6" and their shared uaddr
"format" are listed to prevent any registrant from allocating the
netids "icmp" and "icmp6" for a purpose that would likely cause
confusion.

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RFC 5665 RPC Netids January 2010

5.3. Cross Referencing between the Netid and Format Registry

The last field of the netids registry is used to cross reference with
the last field of the format registry. IANA is under no obligation
to maintain the same numeric values in cross references when updating
each registry; i.e., IANA is free to "re-number" these corresponding
fields. However, if IANA does so, both the netid and format
registries must be updated atomically.

5.4. Port Assignment for NFS over SCTP

Port 2049 is assigned to NFS over SCTP for the sctp and sctp6 netids.

6. References

6.1. Normative References

[1] Srinivasan, R., "Binding Protocols for ONC RPC Version 2",
RFC 1833, August 1995.

[2] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.

[3] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.

6.2. Informative References

[4] Thurlow, R., "RPC: Remote Procedure Call Protocol Specification
Version 2", RFC 5531, May 2009.

[5] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., Beame,
C., Eisler, M., and D. Noveck, "Network File System (NFS)
version 4 Protocol", RFC 3530, April 2003.

[6] Talpey, T. and B. Callaghan, "Remote Direct Memory Access
Transport for Remote Procedure Call", RFC 5666, January 2010.

[7] Stewart, R., Ed., "Stream Control Transmission Protocol",
RFC 4960, September 2007.

[8] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 5226, May 2008.

[9] Postel, J., "Internet Control Message Protocol", STD 5,
RFC 792, September 1981.

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RFC 5665 RPC Netids January 2010

[10] American Telephone and Telegraph Company, "UNIX System V,
Release 4 Programmer's Guide: Networking Interfaces, ISBN
0139470786", 1990.

[11] Postel, J., "Internet Protocol", STD 5, RFC 791,
September 1981.

[12] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998.

[13] Postel, J., "Transmission Control Protocol", STD 7, RFC 793,
September 1981.

[14] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.

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Appendix A. Acknowledgments

Lisa Dusseault, Lars Eggert, Pasi Eronen, Tim Polk, Juergen
Schoenwaelder, and Robert Sparks reviewed the document and gave
valuable feedback.

Author's Address

Mike Eisler
NetApp
5765 Chase Point Circle
Colorado Springs, CO 80919
US

Phone: +1-719-599-9026
EMail: [email protected]

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