draft-ietf-nfsv4-nfs-ulb-v2-05.txt   draft-ietf-nfsv4-nfs-ulb-v2-06.txt 
Network File System Version 4 C. Lever Network File System Version 4 C. Lever
Internet-Draft Oracle Internet-Draft Oracle
Intended status: Standards Track 6 July 2021 Intended status: Standards Track 16 November 2021
Expires: 7 January 2022 Expires: 20 May 2022
Network File System (NFS) Upper-Layer Binding To RPC-Over-RDMA Version 2 Network File System (NFS) Upper-Layer Binding To RPC-Over-RDMA Version 2
draft-ietf-nfsv4-nfs-ulb-v2-05 draft-ietf-nfsv4-nfs-ulb-v2-06
Abstract Abstract
This document specifies Upper-Layer Bindings of Network File System This document specifies Upper-Layer Bindings of Network File System
(NFS) protocol versions to RPC-over-RDMA version 2. (NFS) protocol versions to RPC-over-RDMA version 2.
Note Note
This note is to be removed before publishing as an RFC.
Discussion of this draft takes place on the NFSv4 working group Discussion of this draft takes place on the NFSv4 working group
mailing list (nfsv4@ietf.org), which is archived at mailing list (nfsv4@ietf.org), archived at
https://mailarchive.ietf.org/arch/browse/nfsv4/. Working Group https://mailarchive.ietf.org/arch/browse/nfsv4/. Working Group
information can be found at https://datatracker.ietf.org/wg/nfsv4/ information is available at https://datatracker.ietf.org/wg/nfsv4/
about/. about/.
The source for this draft is maintained in GitHub. Suggested changes Submit suggestions and changes as pull requests at
can be submitted as pull requests at https://github.com/chucklever/ https://github.com/chucklever/i-d-nfs-ulb-v2. Instructions are on
i-d-nfs-ulb-v2. Instructions are on that page as well. that page.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 7 January 2022. This Internet-Draft will expire on 20 May 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 2, line 27 skipping to change at page 2, line 22
provided without warranty as described in the Simplified BSD License. provided without warranty as described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Upper-Layer Binding for NFS Versions 2 and 3 . . . . . . . . 4 3. Upper-Layer Binding for NFS Versions 2 and 3 . . . . . . . . 4
3.1. Reply Size Estimation . . . . . . . . . . . . . . . . . . 4 3.1. Reply Size Estimation . . . . . . . . . . . . . . . . . . 4
3.2. RPC Binding Considerations . . . . . . . . . . . . . . . 5 3.2. RPC Binding Considerations . . . . . . . . . . . . . . . 5
3.3. Transport Considerations . . . . . . . . . . . . . . . . 5 3.3. Transport Considerations . . . . . . . . . . . . . . . . 5
3.3.1. Keep-Alive . . . . . . . . . . . . . . . . . . . . . 5
3.3.2. Replay Detection . . . . . . . . . . . . . . . . . . 6
4. Upper-Layer Bindings for NFS Version 2 and 3 Auxiliary 4. Upper-Layer Bindings for NFS Version 2 and 3 Auxiliary
Protocols . . . . . . . . . . . . . . . . . . . . . . . . 6 Protocols . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. MOUNT, NLM, and NSM Protocols . . . . . . . . . . . . . . 7 4.1. MOUNT, NLM, and NSM Protocols . . . . . . . . . . . . . . 7
4.2. NFSACL Protocol . . . . . . . . . . . . . . . . . . . . . 7 4.2. NFSACL Protocol . . . . . . . . . . . . . . . . . . . . . 7
5. Upper-Layer Binding For NFS Version 4 . . . . . . . . . . . . 7 5. Upper-Layer Binding For NFS Version 4 . . . . . . . . . . . . 7
5.1. DDP-Eligibility . . . . . . . . . . . . . . . . . . . . . 7 5.1. DDP-Eligibility . . . . . . . . . . . . . . . . . . . . . 7
5.2. Reply Size Estimation . . . . . . . . . . . . . . . . . . 9 5.1.1. The NFSv4.2 READ_PLUS operation . . . . . . . . . . . 8
5.3. RPC Binding Considerations . . . . . . . . . . . . . . . 10 5.2. Reply Size Estimation . . . . . . . . . . . . . . . . . . 8
5.4. NFS COMPOUND Requests . . . . . . . . . . . . . . . . . . 10 5.2.1. Reply Size Estimation for Minor Version 0 . . . . . . 9
5.5. NFS Callback Requests . . . . . . . . . . . . . . . . . . 12 5.2.2. Reply Size Estimation for Minor Version 1 and
5.6. Session-Related Considerations . . . . . . . . . . . . . 13 Newer . . . . . . . . . . . . . . . . . . . . . . . . 9
5.7. Transport Considerations . . . . . . . . . . . . . . . . 14 5.3. RPC Binding Considerations . . . . . . . . . . . . . . . 9
5.4. NFS COMPOUND Requests . . . . . . . . . . . . . . . . . . 9
5.4.1. Multiple DDP-eligible Data Items . . . . . . . . . . 10
5.4.2. Chunk List Complexity . . . . . . . . . . . . . . . . 10
5.4.3. NFS Version 4 COMPOUND Example . . . . . . . . . . . 11
5.5. NFS Callback Requests . . . . . . . . . . . . . . . . . . 11
5.5.1. NFS Version 4.0 Callback . . . . . . . . . . . . . . 12
5.5.2. NFS Version 4.1 Callback . . . . . . . . . . . . . . 12
5.6. Session-Related Considerations . . . . . . . . . . . . . 12
5.7. Transport Considerations . . . . . . . . . . . . . . . . 13
5.7.1. Congestion Avoidance . . . . . . . . . . . . . . . . 13
5.7.2. Retransmission and Keep-alive . . . . . . . . . . . . 14
6. Extending NFS Upper-Layer Bindings . . . . . . . . . . . . . 15 6. Extending NFS Upper-Layer Bindings . . . . . . . . . . . . . 15
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 16 9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 17 9.2. Informative References . . . . . . . . . . . . . . . . . 16
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 18
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction 1. Introduction
The RPC-over-RDMA version 2 transport may employ direct data The RPC-over-RDMA version 2 transport can employ direct data
placement to convey data payloads associated with RPC transactions, placement to convey data payloads associated with RPC transactions,
as described in [I-D.ietf-nfsv4-rpcrdma-version-two]. RPC client and as described in [I-D.ietf-nfsv4-rpcrdma-version-two]. As mandated by
server implementations using RPC-over-RDMA version 2 must agree which that document, RPC client and server implementations using RPC-over-
XDR data items and RPC procedures are eligible to use direct data RDMA version 2 MUST agree in advance which XDR data items and RPC
placement (DDP) to ensure successful interoperation. procedures are eligible for direct data placement (DDP).
An Upper-Layer Binding specifies this agreement for one or more An Upper-Layer Binding specifies this agreement for one or more
versions of one RPC program. Other operational details, such as RPC versions of one RPC program. Other operational details, such as RPC
binding assignments, pairing Write chunks with result data items, and binding assignments, pairing Write chunks with result data items, and
reply size estimation, are also specified by such a Binding. reply size estimation, are also specified by such a Binding.
This document contains material required of Upper-Layer Bindings, as This document contains material required of Upper-Layer Bindings, as
specified in Appendix A of [I-D.ietf-nfsv4-rpcrdma-version-two], for specified in Appendix A of [I-D.ietf-nfsv4-rpcrdma-version-two], for
the following NFS protocol versions: the following NFS protocol versions:
skipping to change at page 4, line 28 skipping to change at page 4, line 28
* The pathname argument in the NFS SYMLINK procedure * The pathname argument in the NFS SYMLINK procedure
* The opaque file data result in the NFS READ procedure * The opaque file data result in the NFS READ procedure
* The pathname result in the NFS READLINK procedure * The pathname result in the NFS READLINK procedure
All other argument or result data items in NFS versions 2 and 3 are All other argument or result data items in NFS versions 2 and 3 are
not DDP-eligible. not DDP-eligible.
Whether or not an NFS operation is considered non-idempotent, a Regardless of whether an NFS operation is considered non-idempotent,
transport error might not indicate whether the server has processed a transport error might not indicate whether the server has processed
the arguments of the RPC Call, or whether the server has accessed or the arguments of the RPC Call or whether the server has accessed or
modified client memory associated with that RPC. modified client memory associated with that RPC.
3.1. Reply Size Estimation 3.1. Reply Size Estimation
During the construction of each RPC Call message, a Requester is During the construction of each RPC Call message, a Requester is
responsible for allocating appropriate transport resources to receive responsible for allocating appropriate RDMA resources to receive the
the corresponding Reply message. These resources must be capable of corresponding Reply message. These resources must be capable of
holding the entire Reply, therefore the Requester needs to estimate holding the entire Reply. Therefore the Requester needs to estimate
the maximum possible size of the expected Reply message. the maximum possible size of the expected Reply message.
* In many cases, the expected Reply can fit in one or a few RDMA * Often, the expected Reply can fit in a limited number of RDMA Send
Send messages. The Requester need not provision any RDMA messages. The Requester need not provision any RDMA resources for
resources, relying instead on message continuation to handle the the Reply, relying instead on message continuation to handle the
entire Reply message. entire Reply message.
* In cases where the Requester deems direct data placement to be the * In cases where the Upper Layer Binding permits direct data
most efficient transfer mechanism, it provisions Write chunks placement of the results (DDP), a Requester can provision Write
wherein the Responder can place results. In these cases, the chunks to receive those results. The Requester MUST reliably
Requester must reliably estimate the maximum size of each result estimate the maximum size of each result receive via a Write
that is to be placed in a Write chunk. chunk.
* When the Requester expects an especially large Reply message, it * A Requester that expects a large Reply message can provision a
can provision a combination of a Reply chunk and Write chunks for Reply chunk. The Requester MUST reliably estimate the maximum
result data items. In such cases, the Requester must reliably size of the payload received via the Reply chunk.
estimate the maximum size of each result that is to be placed in a
Write chunk and the maximum size of the remainder to be placed in
the Reply chunk.
A legacy NFS client needs to make every effort to avoid * If RDMA resources are not available to send a Reply, a Responder
retransmission of non-idempotent NFS requests due to underestimated falls back to message continuation.
Reply resources. Thanks to the mechanism of message continuation in
RPC-over-RDMA version 2, the need for such retransmission is greatly A correctly implemented Legacy NFS client thus avoids retransmission
reduced. of non-idempotent NFS requests due to improperly estimated Reply
resources.
3.2. RPC Binding Considerations 3.2. RPC Binding Considerations
Legacy NFS servers traditionally listen for clients on UDP and TCP Legacy NFS servers typically listen for clients on UDP and TCP port
port 2049. Additionally, they register these ports with a local 2049. Additionally, they register these ports with a local
portmapper service [RFC1833]. portmapper service [RFC1833].
A Legacy NFS server supporting RPC-over-RDMA version 2 and A Legacy NFS server supporting RPC-over-RDMA version 2 and
registering itself with the RPC portmapper MAY choose an arbitrary registering itself with the RPC portmapper MAY choose an arbitrary
port, or MAY use the alternative well-known port number for its RPC- port or MAY use the alternative well-known port number for its RPC-
over-RDMA service (see Section 8). The chosen port MAY be registered over-RDMA service (see Section 8). The chosen port MAY be registered
with the RPC portmapper using the netids assigned in Section 12 of with the RPC portmapper using the netids assigned in Section 12 of
[I-D.ietf-nfsv4-rpcrdma-version-two]. [I-D.ietf-nfsv4-rpcrdma-version-two].
3.3. Transport Considerations 3.3. Transport Considerations
Legacy NFS client implementations often rely on a transport-layer
keep-alive mechanism to detect when a legacy server has become
unresponsive. When an NFS server is no longer responsive, client-
side keep-alive terminates the connection, which in turn triggers
reconnection and retransmission of outstanding RPC transactions.
3.3.1. Keep-Alive 3.3.1. Keep-Alive
Legacy NFS client implementations can rely on connection keep-alive
to detect when a Legacy NFS server has become unresponsive. When an
NFS server is no longer responsive, client-side keep-alive terminates
the connection, triggering reconnection and retransmission of
outstanding RPC transactions.
Some RDMA transports (such as the Reliable Connected QP type on Some RDMA transports (such as the Reliable Connected QP type on
InfiniBand) have no keep-alive mechanism. Without a disconnect or InfiniBand) have no keep-alive mechanism. Without a disconnect or
new RPC traffic, such connections can remain alive long after an NFS new RPC traffic, such connections can remain alive long after an NFS
server has become unresponsive or unreachable. Once an NFS client server has become unresponsive or unreachable. Once an NFS client
has consumed all available RPC-over-RDMA version 2 credits on that has consumed all available RPC-over-RDMA version 2 credits on that
transport connection, it awaits a reply indefinitely before sending transport connection, it awaits a reply indefinitely before sending
another RPC request. another RPC request.
Legacy NFS clients SHOULD reserve one RPC-over-RDMA version 2 credit Legacy NFS clients SHOULD reserve one RPC-over-RDMA version 2 credit
to use for periodic server or connection health assessment. Either to use for periodic server or connection health assessment. Either
peer can use this credit to drive an RPC request on an otherwise idle peer can use this credit to drive an RPC request on an otherwise idle
connection, triggering either an affirmative server response or a connection, triggering either an affirmative server response or a
connection termination. connection termination.
3.3.2. Replay Detection 3.3.2. Replay Detection
Legacy NFS servers typically employ request replay detection to Like NFSv4.0, Legacy NFS servers typically employ request replay
reduce the risk of data and file namespace corruption that could detection to reduce the risk of data and file namespace corruption
result when an NFS client retransmits a non-idempotent NFS request. that could result when an NFS client retransmits a non-idempotent NFS
A legacy NFS server can send a cached response when a replay is request. A Legacy NFS server can send a cached response when a
detected, rather than executing the request again. Replay detection replay is detected, rather than executing the request again. Replay
is not perfect, but it is usually adequate. detection is not perfect, but it is usually adequate.
For legacy NFS servers, replay detection commonly utilizes heuristic For Legacy NFS servers, replay detection commonly utilizes heuristic
indicators such as the IP address of the NFS client, the source port indicators such as the IP address of the NFS client, the source port
of the connection, the transaction ID of the request, and the of the connection, the transaction ID of the request, and the
contents of the request's RPC and upper-layer protocol headers. In contents of the request's RPC and upper-layer protocol headers. A
short, replay detection is typically based on a connection tuple and Legacy NFS client is careful to re-use the same source port when
the request's XID. A legacy NFS client is careful to re-use the same reconnecting so that Legacy NFS servers can better detect RPC
source port, if practical, when reconnecting so that legacy NFS retransmission.
servers are better able to detect retransmissions.
However, a legacy NFS client operating over an RDMA transport has no However, a Legacy NFS client operating over an RDMA transport has no
control over connection source ports. It is almost certain that an control over connection source ports. It is almost certain that an
RPC request that is retransmitted on a new connection can never be RPC request retransmitted on a new connection can never be detected
detected as a replay if the legacy NFS server includes the connection as a replay if the receiving Legacy NFS server includes the
source port in its replay detection heuristics. connection source port in its replay detection heuristics.
Therefore a legacy NFS server using an RDMA transport should never Therefore a Legacy NFS server using an RDMA transport should never
use a legacy NFS client connection's source port as part of its NFS use a connection's source port as part of its NFS request replay
request replay detection mechanism. detection mechanism.
4. Upper-Layer Bindings for NFS Version 2 and 3 Auxiliary Protocols 4. Upper-Layer Bindings for NFS Version 2 and 3 Auxiliary Protocols
Storage administrators typically deploy NFS versions 2 and 3 with Storage administrators typically deploy NFS versions 2 and 3 with
several other protocols, sometimes referred to as the "NFS auxiliary several other protocols, sometimes called the "NFS auxiliary
protocols." These are distinct RPC programs that define procedures protocols." These are distinct RPC programs that define procedures
that are not part of the NFS RPC program (100003). The Upper-Layer not part of the NFS RPC program (100003). The Upper-Layer Bindings
Bindings in this section apply to: in this section apply to:
* Versions 2 and 3 of the MOUNT RPC program (100005) [RFC1813] * Versions 2 and 3 of the MOUNT RPC program (100005) [RFC1813]
* Versions 1, 3, and 4 of the NLM RPC program (100021) [RFC1813] * Versions 1, 3, and 4 of the NLM RPC program (100021) [RFC1813]
* Version 1 of the NSM RPC program (100024), described in Chapter 11 * Version 1 of the NSM RPC program (100024), described in Chapter 11
of [XNFS] of [XNFS]
* Versions 2 and 3 of the NFSACL RPC program (100227). The NFSACL * Versions 2 and 3 of the NFSACL RPC program (100227). The NFSACL
program does not have a public definition. In this document it is program does not have a public definition. This document treats
treated as a de facto standard, as there are several the NFSACL program as a de facto standard, as there are several
interoperating implementations. interoperating implementations.
4.1. MOUNT, NLM, and NSM Protocols 4.1. MOUNT, NLM, and NSM Protocols
Historically, NFS/RDMA implementations have chosen to convey the Historically, NFS/RDMA implementations have conveyed the MOUNT, NLM,
MOUNT, NLM, and NSM protocols via TCP. A legacy NFS server and NSM protocols via TCP. A Legacy NFS server implementation MUST
implementation MUST provide support for these protocols via TCP to provide support for these auxiliary protocols via TCP.
enable interoperation of these protocols when NFS/RDMA is in use.
Moreover, there is little benefit from transporting these protocols
via RDMA. Thus this document does not provide an Upper-Layer binding
for them.
4.2. NFSACL Protocol 4.2. NFSACL Protocol
Often legacy clients and servers that support the NFSACL RPC program Legacy NFS clients and servers convey NFSACL procedures on the same
convey NFSACL procedures on the same transport connection and port as transport connection and port as the NFS RPC program (100003).
the NFS RPC program (100003). Utilizing the same port obviates the Utilizing the same port obviates the need for a separate rpcbind
need for separate a rpcbind query to discover server support for this query to discover server support for this RPC program.
RPC program.
ACLs are typically small, but even large ACLs must be encoded and ACLs are typically small, but even large ACLs must be encoded and
decoded to some degree before being made available to users. Thus no decoded to some degree before being being stored in local
data item in this Upper-Layer Protocol is DDP-eligible. filesystems. Thus no data item in this Upper-Layer Protocol is DDP-
eligible.
For procedures whose replies do not include an ACL object, the size For procedures whose replies do not include an ACL object, the size
of a reply is determined directly from the NFSACL RPC program's XDR of each Reply is determined directly from the NFSACL RPC program's
definition. However, legacy client implementations should choose a XDR definition.
maximum size for ACLs based on internal limits, and can rely on
message continuation to handle the a priori unknown size of large ACL The NFSACL protocol does not provide a mechanism to determine the
objects in Replies. size of a received ACL in advance. When preparing for responses that
include ACLs, Legacy NFS clients estimate a maximum reply size based
on limits within their local file systems. If that estimation is
inadequate, a Responder falls back to message continuation.
5. Upper-Layer Binding For NFS Version 4 5. Upper-Layer Binding For NFS Version 4
The Upper-Layer Binding specification in this section applies to The Upper-Layer Binding specification in this section applies to
versions of the NFS RPC program defined in NFS version 4.0 [RFC7530] versions of the NFS RPC program defined in NFS version 4.0 [RFC7530],
NFS version 4.1 [RFC8881] and NFS version 4.2 [RFC7862]. NFS version 4.1 [RFC8881], and NFS version 4.2 [RFC7862].
5.1. DDP-Eligibility 5.1. DDP-Eligibility
Only the following XDR data items in the COMPOUND procedure of all Only the following XDR data items in the COMPOUND procedure of all
NFS version 4 minor versions are DDP-eligible: NFS version 4 minor versions are DDP-eligible:
* The opaque data field in the WRITE4args structure * The opaque data field in the WRITE4args structure
* The linkdata field of the NF4LNK arm in the createtype4 union * The linkdata field of the NF4LNK arm in the createtype4 union
* The opaque data field in the READ4resok structure * The opaque data field in the READ4resok structure
* The linkdata field in the READLINK4resok structure * The linkdata field in the READLINK4resok structure
5.1.1. The NFSv4.2 READ_PLUS operation 5.1.1. The NFSv4.2 READ_PLUS operation
NFS version 4.2 introduces an enhanced READ operation called NFS version 4.2 introduces an enhanced READ operation called
READ_PLUS [RFC7862]. READ_PLUS enables an NFS server to perform data READ_PLUS [RFC7862]. READ_PLUS enables an NFS server to compact
reduction of READ results so that the returned READ data is more returned READ data payloads. No part of a READ_PLUS Reply is DDP-
compact. eligible.
In a READ_PLUS result, returned file content appears as a list of one In a READ_PLUS result, returned file content appears as a list of one
or more of the following items: or more of the following items:
* Regular data content: the same as the result of a traditional READ * Regular data content, the same as the result of a traditional READ
operation. operation
* Unallocated space in a file: where no data has yet been written or * Unallocated space in a file, where no data has been written, or
previously-written data has been removed via a hole-punch previously-written data has been removed via a hole-punch
operation. operation
* A counted pattern. * A counted pattern
Upon receipt of a READ_PLUS result, an NFSv4.2 client expands the Upon receipt of a READ_PLUS result, an NFSv4.2 client expands the
returned list into the preferred local representation of the original returned list into its preferred representation of the original file
file content. content.
Before receiving that result, an NFSv4.2 client typically does not
know how the file's content is organized on the NFS server. Thus it
is not possible to predict the size or structure of a READ_PLUS Reply
in advance. The use of direct data placement is therefore
challenging.
A READ_PLUS content list containing more than one segment of regular Before receiving that result, an NFSv4.2 client is unaware of how the
file data could be conveyed using multiple Write chunks, but only if NFS server has organized the file content. Thus it is not possible
the client knows in advance where those chunks appear in the Reply to predict the size or structure of a READ_PLUS Reply in advance.
Payload stream. Moreover, the usual benefits of hardware-assisted The use of direct data placement is therefore challenging. Moreover,
data placement are entirely waived if the client-side transport must the usual benefits of hardware-assisted data placement are entirely
parse the result of each read I/O. lost if the client must parse the result of each READ I/O.
Therefore this Upper Layer Binding does not make any element of an Therefore this Upper Layer Binding does not make elements of an
NFSv4.2 READ_PLUS Reply DDP-eligible. Further, this Upper Layer NFSv4.2 READ_PLUS Reply DDP-eligible. Further, this Upper Layer
Binding recommends that implementations avoid the use of the Binding recommends that NFS client implemenations avoid using the
READ_PLUS operation on NFS/RDMA mount points. READ_PLUS operation on NFS/RDMA mount points.
5.2. Reply Size Estimation 5.2. Reply Size Estimation
Within NFS version 4, there are certain variable-length result data Within NFS version 4, there are certain variable-length result data
items whose maximum size cannot be estimated by clients reliably items whose maximum size cannot be estimated by clients reliably
because there is no protocol-specified size limit on these result because there is no protocol-specified size limit on these result
arrays. These include: arrays. These include:
* The attrlist4 field * The attrlist4 field
skipping to change at page 9, line 26 skipping to change at page 9, line 14
* Fields in the fs_locations4 and fs_locations_info4 data structures * Fields in the fs_locations4 and fs_locations_info4 data structures
* Fields which pertain to pNFS layout metadata, such as loc_body, * Fields which pertain to pNFS layout metadata, such as loc_body,
loh_body, da_addr_body, lou_body, lrf_body, fattr_layout_types, loh_body, da_addr_body, lou_body, lrf_body, fattr_layout_types,
and fs_layout_types and fs_layout_types
5.2.1. Reply Size Estimation for Minor Version 0 5.2.1. Reply Size Estimation for Minor Version 0
The NFS version 4.0 protocol itself does not impose any bound on the The NFS version 4.0 protocol itself does not impose any bound on the
size of NFS calls or replies. size of NFS Calls or Replies.
Some of the data items enumerated in Section 5.2 (in particular, the
items related to ACLs and fs_locations) make it difficult to predict
the maximum size of NFS version 4.0 replies that interrogate
variable-length fattr4 attributes. Client implementations might rely
upon internal architectural limits to constrain the reply size, but
such limits are not always guaranteed to be reliable.
When an NFS version 4.0 client expects an especially sizeable fattr4 Variable-length fattr4 attributes make it particularly difficult for
result, it can rely on message continuation or provision a Reply clients to predict the maximum size of some NFS version 4.0 Replies.
chunk to enable that server to return that result via explicit RDMA. Client implementations might rely upon internal architectural limits
to constrain the reply size, but such limits are not always reliable.
When an NFS version 4.0 client cannot predict the size of a Reply, it
can rely on message continuation to enable a Reply under any
circumstances.
5.2.2. Reply Size Estimation for Minor Version 1 and Newer 5.2.2. Reply Size Estimation for Minor Version 1 and Newer
In NFS version 4.1 and newer minor versions, the csa_fore_chan_attrs In NFS version 4.1 and newer minor versions, the csa_fore_chan_attrs
argument of the CREATE_SESSION operation contains a argument of the CREATE_SESSION operation contains a
ca_maxresponsesize field. The value in this field can be taken as ca_maxresponsesize field. The value in this field is the absolute
the absolute maximum size of replies generated by an NFS version 4.1 maximum size of replies generated by an NFS version 4.1 server.
server.
An NFS version 4 client can use this value in cases where it is not An NFS version 4 client can use this value when it is impossible to
possible to estimate a reply size upper bound precisely. In estimate a reply size upper bound precisely. In practice, objects
practice, objects such as ACLs, named attributes, layout bodies, and such as ACLs, named attributes, layout bodies, and security labels
security labels are much smaller than this maximum. are much smaller than this maximum.
5.3. RPC Binding Considerations 5.3. RPC Binding Considerations
NFS version 4 servers are required to listen on TCP port 2049, and NFS version 4 servers are required to listen on TCP port 2049 and are
are not required to register with an rpcbind service [RFC7530]. not required to register with an rpcbind service [RFC7530].
Therefore, an NFS version 4 server supporting RPC-over-RDMA version 2 Therefore, an NFS version 4 server supporting RPC-over-RDMA version 2
MUST use the alternative well-known port number for its RPC-over-RDMA MUST use the alternative well-known port number for its RPC-over-RDMA
service (see Section 8 Clients SHOULD connect to this well-known port service defined in Section 8.
without consulting the RPC portmapper (as for NFS version 4 on TCP
transports).
5.4. NFS COMPOUND Requests 5.4. NFS COMPOUND Requests
5.4.1. Multiple DDP-eligible Data Items 5.4.1. Multiple DDP-eligible Data Items
An NFS version 4 COMPOUND procedure can contain more than one An NFS version 4 COMPOUND procedure can contain more than one
operation that carries a DDP-eligible data item. An NFS version 4 operation that carries a DDP-eligible data item. An NFS version 4
client provides XDR Position values in each Read chunk to client provides XDR Position values in each Read chunk to determine
disambiguate which chunk is associated with which argument data item. which chunk is associated with which argument data item. However,
However, NFS version 4 server and client implementations must agree NFS version 4 server and client implementations must agree on how to
in advance on how to pair Write chunks with returned result data pair Write chunks with returned result data items.
items.
In the following lists, a "READ operation" refers to any NFS version A "READ operation" refers to any NFS version 4 operation with a DDP-
4 operation that has a DDP-eligible result data item. An NFS version eligible result data item in the following lists. An NFS version 4
4 client applies the mechanism specified in Section 4.3.2 of client applies the mechanism specified in Section 4.3.2 of
[I-D.ietf-nfsv4-rpcrdma-version-two] to this class of operations as [I-D.ietf-nfsv4-rpcrdma-version-two] to this class of operations as
follows: follows:
* If an NFS version 4 client wishes all DDP-eligible items in an NFS * If an NFS version 4 client wishes all DDP-eligible items in an NFS
reply to be conveyed inline, it leaves the Write list empty. reply to be conveyed inline, it leaves the Write list empty.
An NFS version 4 server acts as follows: An NFS version 4 server acts as follows:
* The first chunk in the Write list MUST be used by the first READ * The first READ operation MUST use the first chunk in the Write
operation in an NFS version 4 COMPOUND procedure. The next Write list in an NFS version 4 COMPOUND procedure. The next READ
chunk is used by the next READ operation, and so on. operation uses the next Write chunk, and so on.
* If an NFS version 4 client has provided a matching non-empty Write * If an NFS version 4 client has provided a matching non-empty Write
chunk, then the corresponding READ operation MUST return its DDP- chunk, then the corresponding READ operation MUST return its DDP-
eligible data item using that chunk. eligible data item using that chunk.
* If an NFS version 4 client has provided an empty matching Write * If an NFS version 4 client has provided an empty matching Write
chunk, then the corresponding READ operation MUST return all of chunk, then the corresponding READ operation MUST return all of
its result data items inline. its result data items inline.
* If a READ operation returns a union arm which does not contain a * If a READ operation returns a union arm which does not contain a
DDP-eligible result, and the NFS version 4 client has provided a DDP-eligible result, and the NFS version 4 client has provided a
matching non-empty Write chunk, an NFS version 4 server MUST matching non-empty Write chunk, an NFS version 4 server MUST
return an empty Write chunk in that Write list position. return an empty Write chunk in that Write list position.
* If there are more READ operations than Write chunks, then * If there are more READ operations than Write chunks, then
remaining NFS Read operations in an NFS version 4 COMPOUND that remaining NFS Read operations in an NFS version 4 COMPOUND that
have no matching Write chunk MUST return their results inline. have no matching Write chunk MUST return their results inline.
5.4.2. Chunk List Complexity 5.4.2. Chunk List Complexity
By default, the RPC-over-RDMA version 2 protocol places limits on the By default, the RPC-over-RDMA version 2 protocol limits the number of
number of chunks or segments that may appear in Read or Write lists chunks or segments that may appear in Read or Write lists (see
(see Section 5.2 of [I-D.ietf-nfsv4-rpcrdma-version-two]). Section 5.2 of [I-D.ietf-nfsv4-rpcrdma-version-two]).
These implementation limits are especially important when Kerberos These implementation limits are significant when Kerberos integrity
integrity or privacy is in use [RFC7861]. GSS services increase the or privacy is in use [RFC7861]. GSS services increase the size of
size of credential material in RPC headers, potentially requiring the credential material in RPC headers, potentially requiring the more
use of a Long message, which increases the complexity of chunk lists frequent use of less efficient Special Payload or Continued Payload
independent of the particular NFS version 4 COMPOUND being conveyed. messages.
In the absence of an explicit transport property exchange that alters NFS version 4 clients follow the prescriptions listed below when
these limits, NFS version 4 clients SHOULD follow the prescriptions constructing RPC-over-RDMA version 2 messages in the absence of an
listed below when constructing RPC-over-RDMA version 2 messages. NFS explicit transport property exchange that alters these limits. NFS
version 4 servers MUST accept and process all such requests. version 4 servers MUST accept and process all such requests.
* The Read list can contain either a Position-Zero Read chunk, one * The Read list can contain either a Call chunk, no more than one
Read chunk with a non-zero Position, or both. Read chunk, or both a Call chunk and one Read chunk.
* The Write list can contain no more than one Write chunk. * The Write list can contain no more than one Write chunk.
NFS version 4 clients wishing to send more complex chunk lists can NFS version 4 clients wishing to send more complex chunk lists can
provide configuration interfaces to bound the complexity of NFS use transport properties to bound the complexity of NFS version 4
version 4 COMPOUNDs, limit the number of elements in scatter-gather COMPOUNDs, limit the number of elements in scatter-gather operations,
operations, and avoid other sources of chunk overruns at the and avoid other sources of chunk overruns at the receiving peer.
receiving peer.
If an NFS version 4 server receives an RPC request via RPC-over-RDMA
version 2 that it cannot process due to chunk list complexity limits,
it SHOULD return one of the following responses to the client:
* A problem is detected by the transport layer while parsing the
transport header in an RPC Call message. The server responds with
an RDMA2_ERROR message with the err field set to ERR_CHUNK.
* A problem is detected during XDR decoding of the RPC Call message
while the RPC layer reassembles the call's XDR stream. The server
responds with an RPC reply with its "reply_stat" field set to
MSG_ACCEPTED and its "accept_stat" field set to GARBAGE_ARGS.
After receiving one of these errors, an NFS version 4 client SHOULD
NOT retransmit the failing request, as the result would be the same
error. It SHOULD terminate the RPC transaction associated with the
XID in the reply without further processing, and report an error to
the RPC consumer.
5.4.3. NFS Version 4 COMPOUND Example 5.4.3. NFS Version 4 COMPOUND Example
The following example shows a Write list with three Write chunks, A, The following example shows a Write list with three Write chunks, A,
B, and C. The NFS version 4 server consumes the provided Write B, and C. The NFS version 4 server consumes the provided Write
chunks by writing the results of the designated operations in the chunks by writing the results of the designated operations in the
compound request (READ and READLINK) back to each chunk. compound request (READ and READLINK) back to each chunk.
Write list: Write list:
A --> B --> C A --> B --> C
NFS version 4 COMPOUND request: NFS version 4 COMPOUND request:
PUTFH LOOKUP READ PUTFH LOOKUP READLINK PUTFH LOOKUP READ PUTFH LOOKUP READ PUTFH LOOKUP READLINK PUTFH LOOKUP READ
| | | | | |
v v v v v v
A B C A B C
If the NFS version 4 client does not want to have the READLINK result If the NFS version 4 client does not want the READLINK result
returned via RDMA, it provides an empty Write chunk for buffer B to returned via RDMA, it provides an empty Write chunk for buffer B to
indicate that the READLINK result must be returned inline. indicate that the READLINK result must be returned inline.
5.5. NFS Callback Requests 5.5. NFS Callback Requests
The NFS version 4 family of protocols support server-initiated The NFS version 4 family of protocols supports server-initiated
callbacks to notify NFS version 4 clients of events such as recalled callbacks to notify NFS version 4 clients of events such as recalled
delegations. delegations.
5.5.1. NFS Version 4.0 Callback 5.5.1. NFS Version 4.0 Callback
An NFS version 4.0 client uses the SETCLIENTID operation to advertise An NFS version 4.0 client uses the SETCLIENTID operation for
the IP address, port, and netid of its NFS version 4.0 callback advertising the IP address, port, and netid of its NFS version 4.0
service. When an NFS version 4.0 server provides a backchannel callback service. When an NFS version 4.0 server provides a
service to an NFS version 4.0 client that uses RPC-over-RDMA version backchannel service to an NFS version 4.0 client that uses RPC-over-
2 for its forward channel, the server MUST advertise the backchannel RDMA version 2 for its forward channel, the server MUST advertise the
service using either the "tcp" or "tcp6" netid. backchannel service using either the "tcp" or "tcp6" netid.
Because the backchannel does not operate on RPC-over-RDMA, no XDR Because the NFSv4.0 backchannel does not operate on RPC-over-RDMA,
data item in the NFS version 4.0 callback RPC program is DDP- this document does not specify an Upper-Layer binding for the NFSv4.0
eligible. backchannel RPC program.
5.5.2. NFS Version 4.1 Callback 5.5.2. NFS Version 4.1 Callback
In NFS version 4.1 and newer minor versions, callback operations may In NFS version 4.1 and newer minor versions, callback operations may
appear on the same connection that is in use for NFS version 4 appear on the same connection that is in use for NFS version 4
forward channel client requests. NFS version 4 clients and servers forward channel client requests. NFS version 4 clients and servers
MUST use the mechanisms described in Section 4.5 of MUST use the mechanisms described in Section 4.5 of
[I-D.ietf-nfsv4-rpcrdma-version-two] to convey backchannel operations [I-D.ietf-nfsv4-rpcrdma-version-two] to convey backchannel operations
on an RPC-over-RDMA version 2 transport. on an RPC-over-RDMA version 2 transport.
The csa_back_chan_attrs argument of the CREATE_SESSION operation The csa_back_chan_attrs argument of the CREATE_SESSION operation
contains a ca_maxresponsesize field. The value in this field is the contains a ca_maxresponsesize field. The value in this field is the
absolute maximum size of backchannel replies generated by a replying absolute maximum size of backchannel replies generated by a replying
NFS version 4 client. NFS version 4 client.
There are no DDP-eligible data items in callback procedures defined There are no DDP-eligible data items in callback procedures defined
in NFS version 4.1 or NFS version 4.2. However, some callback in NFS version 4.1 or NFS version 4.2. However, some callback
operations, such as messages that convey device ID information, can operations, such as messages that convey device ID information, can
be sizeable. A sender can use Message Continuation or a Long message be sizeable. A sender can use Message Continuation or a Special
in this situation. Payload message in this situation.
When an NFS version 4.1 client can support Long Calls in its When an NFS version 4.1 client can support Special Payload Calls in
backchannel, it reports a backchannel ca_maxrequestsize that is its backchannel, it reports a backchannel ca_maxrequestsize that is
larger than the connection's inline thresholds. Otherwise, an NFS larger than the connection's inline thresholds. Otherwise, an NFS
version 4 server MUST use only Short messages to convey backchannel version 4 server MUST use only Simple Payload or Continued Payload
operations. messages to convey backchannel operations.
5.6. Session-Related Considerations 5.6. Session-Related Considerations
The presence of an NFS version 4 session (as defined in [RFC8881]) The presence of an NFS version 4 session (as defined in [RFC8881])
does not effect the operation of RPC-over-RDMA version 2. None of does not affect the operation of RPC-over-RDMA version 2. None of
the operations introduced to support NFS sessions (e.g., the SEQUENCE the operations introduced to support NFS sessions (e.g., the SEQUENCE
operation) contain DDP-eligible data items. There is no need to operation) contain DDP-eligible data items. There is no need to
match the number of session slots with the number of available RPC- match the number of session slots with the available RPC-over-RDMA
over-RDMA version 2 credits. version 2 credits.
However, there are a few new cases where an RPC transaction can fail. However, there are a few new cases where an RPC transaction can fail.
For example, a Requester might receive, in response to an RPC For example, a Requester might receive, in response to an RPC
request, an RDMA2_ERROR message with a rdma_err value of ERR_CHUNK. request, an RDMA2_ERROR message with a rdma_err value of
These situations are not different from existing RPC errors, which an RDMA2_ERR_BADXDR. These situations are not different from existing
NFS session implementation can already handle for other transport RPC errors, which an NFS session implementation can already handle
types. Moreover, there might be no SEQUENCE result available to the for other transport types. Moreover, there might be no SEQUENCE
Requester to distinguish whether failure occurred before or after the result available to the Requester to distinguish whether failure
Responder executed the requested operations. occurred before or after the Responder executed the requested
operations.
When a transport error occurs (e.g., an RDMA2_ERROR type message is When a transport error occurs (e.g., an RDMA2_ERROR type message is
received), the Requester proceeds, as usual, to match the incoming received), the Requester proceeds, as usual, to match the incoming
XID value to a waiting RPC Call. The Requester terminates the RPC XID value to a waiting RPC Call. The Requester terminates the RPC
transaction and reports the result status to the RPC consumer. The transaction and reports the result status to the RPC consumer. The
Requester's session implementation then determines the session ID and Requester's session implementation then determines the session ID and
slot for the failed request and performs slot recovery to make that slot for the failed request and performs slot recovery to make that
slot usable again. Otherwise, that slot could be rendered slot usable again. Otherwise, that slot is rendered permanently
permanently unavailable. unavailable.
When an NFS session is not present (for example, when NFS version 4.0 When an NFS session is not present (for example, when NFS version 4.0
is in use), a transport error does not indicate whether the server is in use), a transport error does not indicate whether the server
has processed the arguments of the RPC Call, or whether the server has processed the arguments of the RPC Call, or whether the server
has accessed or modified client memory associated with that RPC. has accessed or modified client memory associated with that RPC.
5.7. Transport Considerations 5.7. Transport Considerations
5.7.1. Congestion Avoidance 5.7.1. Congestion Avoidance
skipping to change at page 15, line 8 skipping to change at page 14, line 13
an NFS version 4.1 transport. an NFS version 4.1 transport.
RPC-over-RDMA version 2 utilizes only reliable, connection-oriented RPC-over-RDMA version 2 utilizes only reliable, connection-oriented
transports that guarantee in-order delivery, meeting all the above transports that guarantee in-order delivery, meeting all the above
requirements for NFS version 4.0 and 4.1. See Section 4.2.1 of requirements for NFS version 4.0 and 4.1. See Section 4.2.1 of
[I-D.ietf-nfsv4-rpcrdma-version-two] for more details. [I-D.ietf-nfsv4-rpcrdma-version-two] for more details.
5.7.2. Retransmission and Keep-alive 5.7.2. Retransmission and Keep-alive
NFS version 4 client implementations often rely on a transport-layer NFS version 4 client implementations often rely on a transport-layer
keep-alive mechanism to detect when an NFS version 4 server has connection keep-alive mechanism to detect when an NFS version 4
become unresponsive. When an NFS server is no longer responsive, server has become unresponsive. When an NFS server is no longer
client-side keep-alive terminates the connection, which in turn responsive, client-side keep-alive terminates the connection,
triggers reconnection and RPC retransmission. triggering reconnection and RPC retransmission.
Some RDMA transports (such as the Reliable Connected QP type on Some RDMA transports (such as the Reliable Connected QP type on
InfiniBand) have no keep-alive mechanism. Without a disconnect or InfiniBand) have no keep-alive mechanism. Without a disconnect or
new RPC traffic, such connections can remain alive long after an NFS new RPC traffic, such connections can remain alive long after an NFS
server has become unresponsive. Once an NFS client has consumed all server has become unresponsive. Once an NFS client has consumed all
available RPC-over-RDMA version 2 credits on that transport available RPC-over-RDMA version 2 credits on that transport
connection, it indefinitely awaits a reply before sending another RPC connection, it indefinitely awaits a reply before sending another RPC
request. request.
NFS version 4 clients SHOULD reserve one RPC-over-RDMA version 2 NFS version 4 peers SHOULD reserve one RPC-over-RDMA version 2 credit
credit to use for periodic server or connection health assessment. for periodic server or connection health assessment. Either peer can
Either peer can use this credit to drive an RPC request on an use this credit to drive an RPC request on an otherwise idle
otherwise idle connection, triggering either a quick affirmative connection, triggering either a quick affirmative server response or
server response or immediate connection termination. immediate connection termination.
In addition to network partition and request loss scenarios, RPC- In addition to network partition and request loss scenarios, RPC-
over-RDMA version 2 transport connections can be terminated when a over-RDMA version 2 peers can terminate a connection when a Transport
Transport header is malformed, Reply messages exceed receive header is malformed or when too many RPC-over-RDMA messages are sent
resources, or when too many RPC-over-RDMA messages are sent at once. without a credit update. In such cases:
In such cases:
* If a transport error occurs (e.g., an RDMA2_ERROR type message is * If a transport error occurs (e.g., an RDMA2_ERROR type message is
received) before the disconnect or instead of a disconnect, the received) just before the disconnect or instead of a disconnect,
Requester MUST respond to that error as prescribed by the the Requester MUST respond to that error as prescribed by the
specification of the RPC transport. Then the NFS version 4 rules specification of the RPC transport. Then the NFS version 4 rules
for handling retransmission apply. for handling retransmission apply.
* If there is a transport disconnect and the Responder has provided * If there is a transport disconnect and the Responder has provided
no other response for a request, then only the NFS version 4 rules no other response for a request, then only the NFS version 4 rules
for handling retransmission apply. for handling retransmission apply.
6. Extending NFS Upper-Layer Bindings 6. Extending NFS Upper-Layer Bindings
RPC programs such as NFS are required to have an Upper-Layer Binding RPC programs such as NFS must have an Upper-Layer Binding
specification to interoperate on RPC-over-RDMA version 2 transports specification to operate on an RPC-over-RDMA version 2 transport
[I-D.ietf-nfsv4-rpcrdma-version-two]. Via standards action, the [I-D.ietf-nfsv4-rpcrdma-version-two]. Via standards action, the
Upper-Layer Binding specified in this document can be extended to Upper-Layer Binding specified in this document can be extended to
cover versions of the NFS version 4 protocol specified after NFS cover versions of the NFS version 4 protocol specified after NFS
version 4 minor version 2, or to cover separately published version 4 minor version 2, or to cover separately published
extensions to an existing NFS version 4 minor version, as described extensions to an existing NFS version 4 minor version, as described
in [RFC8178]. in [RFC8178].
7. Security Considerations 7. Security Considerations
RPC-over-RDMA version 2 supports all RPC security models, including RPC-over-RDMA version 2 supports all RPC security models, including
skipping to change at page 16, line 20 skipping to change at page 15, line 31
and results does not affect this since it changes only the method of and results does not affect this since it changes only the method of
data transfer. Because the current document defines only the binding data transfer. Because the current document defines only the binding
of the NFS protocols atop RPC-over-RDMA version 2 of the NFS protocols atop RPC-over-RDMA version 2
[I-D.ietf-nfsv4-rpcrdma-version-two], all relevant security [I-D.ietf-nfsv4-rpcrdma-version-two], all relevant security
considerations are, therefore, described at that layer. considerations are, therefore, described at that layer.
8. IANA Considerations 8. IANA Considerations
The use of direct data placement in NFS introduces a need for an The use of direct data placement in NFS introduces a need for an
additional port number assignment for networks that share traditional additional port number assignment for networks that share traditional
UDP and TCP port spaces with RDMA services. The iWARP protocol is UDP and TCP port spaces with RDMA services. The DDP protocol is such
such an example [RFC5040] [RFC5041]. an example [RFC5041].
For this purpose, the current document specifies a set of transport For this purpose, the current document lists a set of port number
protocol port number assignments. IANA has assigned the following assignments that IANA has already assigned for NFS/RDMA in the IANA
ports for NFS/RDMA in the IANA port registry, according to the port registry, according to the guidelines described in [RFC6335].
guidelines described in [RFC6335].
nfsrdma 20049/tcp Network File System (NFS) over RDMA nfsrdma 20049/tcp Network File System (NFS) over RDMA
nfsrdma 20049/udp Network File System (NFS) over RDMA nfsrdma 20049/udp Network File System (NFS) over RDMA
nfsrdma 20049/sctp Network File System (NFS) over RDMA nfsrdma 20049/sctp Network File System (NFS) over RDMA
The current document should be added as a reference for the nfsrdma The author requests that IANA add the current document as a reference
port assignments. The current document does not alter these for the existing nfsrdma port assignments. This document does not
assignments. alter these assignments.
9. References 9. References
9.1. Normative References 9.1. Normative References
[I-D.ietf-nfsv4-rpcrdma-version-two] [I-D.ietf-nfsv4-rpcrdma-version-two]
Lever, C. and D. Noveck, "RPC-over-RDMA Version 2 Lever, C. and D. Noveck, "RPC-over-RDMA Version 2
Protocol", Work in Progress, Internet-Draft, draft-ietf- Protocol", Work in Progress, Internet-Draft, draft-ietf-
nfsv4-rpcrdma-version-two-05, 6 July 2021, nfsv4-rpcrdma-version-two-05, 6 July 2021,
<https://datatracker.ietf.org/doc/html/draft-ietf-nfsv4- <https://datatracker.ietf.org/doc/html/draft-ietf-nfsv4-
rpcrdma-version-two-05>. rpcrdma-version-two-05>.
[RFC1833] Srinivasan, R., "Binding Protocols for ONC RPC Version 2", [RFC1833] Srinivasan, R., "Binding Protocols for ONC RPC Version 2",
RFC 1833, DOI 10.17487/RFC1833, August 1995, RFC 1833, DOI 10.17487/RFC1833, August 1995,
<https://www.rfc-editor.org/info/rfc1833>. <https://www.rfc-editor.org/rfc/rfc1833>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA) Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165, Transport Protocol Port Number Registry", BCP 165,
RFC 6335, DOI 10.17487/RFC6335, August 2011, RFC 6335, DOI 10.17487/RFC6335, August 2011,
<https://www.rfc-editor.org/info/rfc6335>. <https://www.rfc-editor.org/rfc/rfc6335>.
[RFC7530] Haynes, T., Ed. and D. Noveck, Ed., "Network File System [RFC7530] Haynes, T., Ed. and D. Noveck, Ed., "Network File System
(NFS) Version 4 Protocol", RFC 7530, DOI 10.17487/RFC7530, (NFS) Version 4 Protocol", RFC 7530, DOI 10.17487/RFC7530,
March 2015, <https://www.rfc-editor.org/info/rfc7530>. March 2015, <https://www.rfc-editor.org/rfc/rfc7530>.
[RFC7861] Adamson, A. and N. Williams, "Remote Procedure Call (RPC) [RFC7861] Adamson, A. and N. Williams, "Remote Procedure Call (RPC)
Security Version 3", RFC 7861, DOI 10.17487/RFC7861, Security Version 3", RFC 7861, DOI 10.17487/RFC7861,
November 2016, <https://www.rfc-editor.org/info/rfc7861>. November 2016, <https://www.rfc-editor.org/rfc/rfc7861>.
[RFC7862] Haynes, T., "Network File System (NFS) Version 4 Minor [RFC7862] Haynes, T., "Network File System (NFS) Version 4 Minor
Version 2 Protocol", RFC 7862, DOI 10.17487/RFC7862, Version 2 Protocol", RFC 7862, DOI 10.17487/RFC7862,
November 2016, <https://www.rfc-editor.org/info/rfc7862>. November 2016, <https://www.rfc-editor.org/rfc/rfc7862>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
[RFC8881] Noveck, D., Ed. and C. Lever, "Network File System (NFS) [RFC8881] Noveck, D., Ed. and C. Lever, "Network File System (NFS)
Version 4 Minor Version 1 Protocol", RFC 8881, Version 4 Minor Version 1 Protocol", RFC 8881,
DOI 10.17487/RFC8881, August 2020, DOI 10.17487/RFC8881, August 2020,
<https://www.rfc-editor.org/info/rfc8881>. <https://www.rfc-editor.org/rfc/rfc8881>.
9.2. Informative References 9.2. Informative References
[RFC1094] Nowicki, B., "NFS: Network File System Protocol [RFC1094] Nowicki, B., "NFS: Network File System Protocol
specification", RFC 1094, DOI 10.17487/RFC1094, March specification", RFC 1094, DOI 10.17487/RFC1094, March
1989, <https://www.rfc-editor.org/info/rfc1094>. 1989, <https://www.rfc-editor.org/rfc/rfc1094>.
[RFC1813] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS [RFC1813] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS
Version 3 Protocol Specification", RFC 1813, Version 3 Protocol Specification", RFC 1813,
DOI 10.17487/RFC1813, June 1995, DOI 10.17487/RFC1813, June 1995,
<https://www.rfc-editor.org/info/rfc1813>. <https://www.rfc-editor.org/rfc/rfc1813>.
[RFC5040] Recio, R., Metzler, B., Culley, P., Hilland, J., and D.
Garcia, "A Remote Direct Memory Access Protocol
Specification", RFC 5040, DOI 10.17487/RFC5040, October
2007, <https://www.rfc-editor.org/info/rfc5040>.
[RFC5041] Shah, H., Pinkerton, J., Recio, R., and P. Culley, "Direct [RFC5041] Shah, H., Pinkerton, J., Recio, R., and P. Culley, "Direct
Data Placement over Reliable Transports", RFC 5041, Data Placement over Reliable Transports", RFC 5041,
DOI 10.17487/RFC5041, October 2007, DOI 10.17487/RFC5041, October 2007,
<https://www.rfc-editor.org/info/rfc5041>. <https://www.rfc-editor.org/rfc/rfc5041>.
[RFC8178] Noveck, D., "Rules for NFSv4 Extensions and Minor [RFC8178] Noveck, D., "Rules for NFSv4 Extensions and Minor
Versions", RFC 8178, DOI 10.17487/RFC8178, July 2017, Versions", RFC 8178, DOI 10.17487/RFC8178, July 2017,
<https://www.rfc-editor.org/info/rfc8178>. <https://www.rfc-editor.org/rfc/rfc8178>.
[XNFS] The Open Group, "Protocols for Interworking: XNFS, Version [XNFS] The Open Group, "Protocols for Interworking: XNFS, Version
3W", February 1998. 3W", January 1998.
Acknowledgments Acknowledgments
Thanks to Tom Talpey, who contributed the text of Section 5.4.2. Thanks to Tom Talpey, who contributed the text of Section 5.4.2.
David Noveck contributed the text of Section 5.6 and Section 6. The David Noveck contributed the text of Section 5.6 and Section 6. The
author also wishes to thank Bill Baker and Greg Marsden for their author also wishes to thank Bill Baker and Greg Marsden for their
support of this work. support of this work.
Special thanks go to Transport Area Directors Zaheduzzaman Sarker, Special thanks go to Transport Area Directors Zaheduzzaman Sarker,
NFSV4 Working Group Chairs Brian Pawlowski, and David Noveck, and NFSV4 Working Group Chairs Brian Pawlowski, and David Noveck, and
 End of changes. 96 change blocks. 
279 lines changed or deleted 254 lines changed or added

This html diff was produced by rfcdiff 1.48. The latest version is available from http://tools.ietf.org/tools/rfcdiff/