wdiff draft-ietf-nfsv4-rfc5667bis-00.txt draft-ietf-nfsv4-rfc5667bis-01.txt

Network File System Version 4 C. Lever, Ed.
Internet-Draft Oracle
Obsoletes: 5667 (if approved) June 13, 30, 2016
Intended status: Standards Track
Expires: December 15, 2016 January 1, 2017

Network File System (NFS) Direct Data Placement
draft-ietf-nfsv4-rfc5667bis-00 Upper Layer Binding To RPC-Over-RDMA
draft-ietf-nfsv4-rfc5667bis-01

Abstract

This document defines specifies the bindings Upper Layer Bindings of the various Network File
System (NFS) protocol versions to the Remote Direct Memory Access (RDMA) operations
supported by the RPC-over-RDMA transport protocol. It describes the transports. Such
Upper Layer Bindings are required to enable RPC-based protocols to
use of direct data placement by means of server-initiated RDMA
operations into client-supplied buffers for implementations of NFS
versions 2, 3, 4, and 4.1 over such an RDMA transport. when conveying large data payloads on RPC-
over-RDMA transports. This document obsoletes RFC 5667.

Status of This Memo

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provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on December 15, 2016. January 1, 2017.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 3
1.2. Changes Since RFC 5667 . . . . . . . . . . . . . . . . . 3
1.3. Planned Changes To This Document . . . . . . . . . . . . 2 4
2. Transfers from NFS Client to Conveying NFS Server Operations On RPC-Over-RDMA Transports . . . . 4
2.1. Use Of The Read List . . . . . . . 3
3. Transfers from NFS Server to NFS Client . . . . . . . . . . . 3
4. NFS Versions 2 and 3 Mapping 4
2.2. Use Of The Write List . . . . . . . . . . . . . . . . . . 5
5.
2.3. Construction Of Individual Chunks . . . . . . . . . . . . 5
2.4. Use Of Long Calls And Replies . . . . . . . . . . . . . . 5
3. NFS Versions 2 And 3 Upper Layer Binding . . . . . . . . . . 5
4. NFS Version 4 Mapping Upper Layer Binding . . . . . . . . . . . . . . 6
4.1. NFS Version 4 COMPOUND Considerations . . . . . . 6
5.1. . . . . 7
4.2. NFS Version 4 Callbacks . . . . . . . . . . . . . . . . . 8
6.
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
7. 8
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8.
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9
9.
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. 9
8.1. Normative References . . . . . . . . . . . . . . . . . . 10
9.2. 9
8.2. Informative References . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11

1. Introduction

The

Remote Direct Memory Access (RDMA) Transport for Remote Procedure
Call (RPC) Call,
Version One [I-D.ietf-nfsv4-rfc5666bis] allows an RPC client
application (RPC-over-RDMA) enables the
use of direct data placement to post buffers in a Chunk list for specific arguments
and results from an accelerate the transmission of large
data payloads associated with RPC call. The RDMA transactions.

Each RPC-over-RDMA transport header conveys this
list of client buffer addresses to the server where the application can associate them with client convey lists of memory
locations involved in direct transfers of data and use RDMA operations to
transfer the results directly payloads. These
memory locations correspond to and from the posted buffers on the
client. The XDR data items defined in an Upper
Layer Protocol (such as NFS).

To facilitate interoperation, RPC client and server implementations
must agree on a consistent mapping of
posted buffers to RPC. what XDR data items in which RPC procedures are
eligible for direct data placement (DDP).

This document details specifies the mapping for set of XDR data items in each
version of the
following NFS protocol versions that are eligible for DDP. It also
contains additional material required of Upper Layer Bindings as
specified in [I-D.ietf-nfsv4-rfc5666bis].

o NFS Version 2 [RFC1094]
o NFS Version 3 [RFC1813]

o NFS Version 4.0 [RFC7530] [RFC5661].

o NFS Version 4.1 [RFC5661]

o NFS Version 4.2 [I-D.ietf-nfsv4-minorversion2]

The Upper Layer Binding specified in this document can be extended to
cover the addition of new DDP-eligible XDR data items defined by
versions of the NFS version 4 protocol specified after this document
has been ratified.

1.1. 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 [RFC2119].

1.2. Planned Changes To This Document Since RFC 5667

Corrections and updates made necessary by new language in
[I-D.ietf-nfsv4-rfc5666bis] has been introduced. For example,
references to deprecated features of RPC-over-RDMA Version One, such
as RDMA_MSGP, and the use of the Read list for handling RPC replies,
has been removed. The term "mapping" has been replaced with the term
"binding" or "Upper Layer Binding" throughout the document. Material
that duplicates what is in [I-D.ietf-nfsv4-rfc5666bis] has been
deleted.

Material required by [I-D.ietf-nfsv4-rfc5666bis] for Upper Layer
Bindings that was not present in [RFC5667] has been added, including
discussion of how each NFS version properly estimates the maximum
size of RPC replies.

The following changes will be have been made, relative to [RFC5667]:

o Ambiguous or erroneous uses of RFC2119 terms have been corrected.

o References to [RFC5666] will be replaced with references to
[I-D.ietf-nfsv4-rfc5666bis]. Corrections and updates relative to
new language in [I-D.ietf-nfsv4-rfc5666bis] will be introduced. specific data movement mechanisms have been made
generic or removed.

o References to obsolete RFCs will be have been replaced.

o Technical corrections have been made. For example, the mention of
12KB and 36KB inline thresholds have been removed. The reference
to a non-existant NFSv4 NFS version 4 SYMLINK operation will be has been
replaced with NFSv4 NFS version 4 CREATE(NF4LNK).

o The An IANA Considerations Section has replaced the "Port Usage
Considerations" Section.

o Code excerpts have been removed, and figures have been modernized.

o Language inconsistent with or contradictory to
[I-D.ietf-nfsv4-rfc5666bis] has been removed from Sections 2 and
3, and both Sections have been combined into Section 2 in the
present document.

o An explicit discussion of 12KB NFSv4.0 and 36KB inline threshold NFSv4.1 backchannel
operation will be removed. replace the previous treatment of callback
operations. No NFSv4.x callback operation is DDP-eligible.

o The binding for NFSv4.1 has been completed. No additional DDP-
eligible operations exist in NFSv4.1.

o A binding for NFSv4.2 has been added that includes discussion of NFSv4
new data-bearing operations like READ_PLUS.

1.3. Planned Changes To This Document

The following changes are planned, relative to [RFC5667]:

o The discussion of NFS version 4 COMPOUND handling will be
completed.

o An explicit discussion of NFSv4.0 and NFSv4.1 backchannel
operation Remarks about handling DDP-eligibility violations will be
introduced.

o An IANA Considerations section A discussion of how the NFS binding to RPC-over-RDMA is required extended
by IDNITS.

o Code excerpts standards action will be modernized.

Other minor changes and editorial corrections may also be made. added.

2. Transfers from Conveying NFS Client Operations On RPC-Over-RDMA Transports

Definitions of terminology and a general discussion of how RPC-over-
RDMA is used to convey RPC transactions can be found in
[I-D.ietf-nfsv4-rfc5666bis]. In this section, these general
principals are applied to the specifics of the NFS Server protocol.

2.1. Use Of The RDMA Read list, List

The Read list in the RDMA each RPC-over-RDMA transport header, allows an RPC
client to marshal RPC call data selectively. Large chunks header represents a set
of data, memory regions containing DDP-eligible NFS argument data. Large
data items, such as the file data payload of an NFS WRITE request, MAY be
are referenced by
an RDMA the Read list and be moved efficiently and directly placed by an
RDMA Read operation initiated by the server.

The process of identifying these chunks for the RDMA Read list can be
implemented entirely within the RPC layer. It is transparent to the
upper-level protocol, such as NFS. For instance, the file data
portion of an NFS WRITE request can be selected as an RDMA "chunk"
within the eXternal Data Representation (XDR) marshaling code of RPC
based on a size criterion, independently of the NFS protocol layer.
The directly into server
memory.

XDR unmarshaling code on the receiving system can identify NFS server identifies the correspondence
between Read chunks and protocol elements particular NFS arguments via the XDR
position chunk
Position value encoded in the Read chunk entry.

RPC RDMA each Read chunks chunk.

2.2. Use Of The Write List

The Write list in each RPC-over-RDMA transport header represents a
set of memory regions that can receive DDP-eligible NFS result data.
Large data items such as the payload of an NFS READ request are employed
referenced by this NFS mapping the Write list and placed directly into client memory.

Each Write chunk corresponds to convey a specific NFS XDR data to the server item in a manner that may be directly
placed. The following sections describe this mapping for versions of
the NFS protocol.

3. Transfers from an NFS Server to
reply. This document specifies how NFS Client

The RDMA Write list, in the RDMA transport header, allows the client
to post one or more buffers into which the and server will RDMA Write
designated result chunks directly. If
implementations identify the client sends a null correspondence between Write
list, then results from the RPC call will be returned either as an
inline reply, as chunks in an RDMA and
each XDR result.

2.3. Construction Of Individual Chunks

Each Read chunk is represented as a list of server-posted
buffers, or in a client-posted reply buffer.

Each posted buffer in a segments at the same XDR
Position, and each Write list chunk is represented as an array of
memory
segments. This allows the An NFS client some flexibility in
submitting discontiguous memory segments into which the server will
scatter thus has the result. Each segment is described by flexibility to advertise a triplet
consisting set
of the segment handle or steering tag (STag), segment
length, and memory address or offset.

struct xdr_rdma_segment {
uint32 handle; /* Registered discontiguous memory handle */
uint32 length; /* Length of the chunk regions in bytes */
uint64 offset; /* Chunk virtual address or offset */
};

struct xdr_write_chunk {
struct xdr_rdma_segment target<>;
};

struct xdr_write_list {
struct xdr_write_chunk entry;
struct xdr_write_list *next;
};

The sum of the segment lengths yields the total size of the buffer, which MUST be large enough to accept the result. send or receive a single
DDP-eligible data item.

2.4. Use Of Long Calls And Replies

Small RPC messages are conveyed using RDMA Send operations which are
of limited size. If the buffer an NFS request is too small, the server MUST return large to be conveyed via
an XDR encode error. The server
MUST return the result RDMA Send, and there are no DDP-eligible data for a posted buffer by progressively
filling its segments, perhaps leaving some trailing segments unfilled
or partially full if the size of the result is less than the total
size of items that can be
removed, an NFS client must send the buffer segments. request using a Long Call. The server returns the RDMA Write list to the
entire NFS request is sent in a special Read chunk.

If a client with the segment
length fields overwritten to indicate the amount of data RDMA written expects that an NFS reply will be too large to each segment. Results returned by direct placement MUST NOT be
returned by other methods, e.g., by Read
conveyed via an RDMA Send, it provides a Reply chunk list or inline. If no
result data at all is returned for the element, the server places no
data in the buffer(s), but does return zeros in the segment length
fields corresponding to the result.

The RPC-over-
RDMA Write list allows the client to provide multiple result
buffers -- each buffer maps to a specific result in transport header conveying the reply. The NFS client and server implementations agree by specifying the mapping
of results to buffers for each RPC procedure. request. The following sections
describe this mapping for versions of the NFS protocol.

Through server can
place the use of RDMA Write lists in entire NFS requests, it is not
necessary to employ the RDMA Read lists reply in the NFS replies, as Reply chunk.

These are described in the RPC-over-RDMA protocol. This enables more efficient
operation, by avoiding the need for the server to expose buffers for
RDMA, and also avoiding "RDMA_DONE" exchanges. Clients MAY
additionally employ RDMA Reply chunks to receive entire messages, as
described detail in [I-D.ietf-nfsv4-rfc5666bis].

3. NFS Versions 2 and And 3 Mapping

A single RDMA Write list entry MAY be posted by the Upper Layer Binding

An NFS client MAY send a single Read chunk to receive
either the supply opaque file data from a READ request
for an NFS WRITE procedure, or the pathname from
a READLINK request. The for an NFS SYMLINK
procedure. For all other NFS procedures, the server MUST ignore Read
chunks that have a Write list for any
other NFS procedure, as well as any Write list entries non-zero value in their Position fields, and Read
chunks beyond the first in the Read list.

Similarly, an NFS client MAY provide a single RDMA Read list entry MAY be posted by the client Write chunk to supply the receive
either opaque file data for a WRITE request from an NFS READ procedure, or the pathname
for a SYMLINK request.
from an NFS READLINK procedure. The server MUST ignore any Read the Write
list for any other NFS procedures, as well as additional Read list entries procedure, and any Write chunks beyond the
first in the Write list.

Because there

There are no NFS version 2 or 3 requests procedures that transfer bulk have DDP-eligible
data items in both directions, it is not necessary to post requests
containing both Write their Call and Read lists. Any unneeded Read Reply. However, if an NFS client
is sending a Long Call or Reply, it MAY provide a combination of Read
list, Write
lists are ignored by list, and/or a Reply chunk in the server.

In same transaction.

NFS clients already successfully estimate the case where maximum reply size of
each operation in order to provide an adequate set of buffers to
receive each NFS reply. An NFS client provides a Reply chunk when
the outgoing request or expected incoming maximum possible reply size is larger than the maximum size supported on the connection, it is
possible for client's responder
inline threshold.

How does the RPC layer to post server respond if the entire message or result in a
special "RDMA_NOMSG" message type that is transferred entirely by
RDMA. This is implemented in RPC, below NFS, and therefore client has no
effect on the message contents.

Non-RDMA (inline) not provided enough
Write list resources to handle an NFS WRITE transfers MAY OPTIONALLY employ the
"RDMA_MSGP" padding method described in the RPC-over-RDMA protocol,
if the appropriate value for or READLINK reply? How
does the server is known to the client.
Padding allows respond if the opaque file data client has not provided enough Reply
chunk resources to arrive at the server in handle an
aligned fashion, which may improve server performance.

The NFS version 2 and 3 protocols are frequently limited in practice
to requests containing less than or equal reply?

4. NFS Version 4 Upper Layer Binding

This specification applies to 8 kilobytes NFS Version 4.0 [RFC7530], NFS Version
4.1 [RFC5661], and 32
kilobytes NFS Version 4.2 [I-D.ietf-nfsv4-minorversion2].
It also applies to the callback protocols associated with each of data, respectively. In
these cases, it is often
practical to support basic operation without employing minor versions.

An NFS client MAY send a
configuration exchange as discussed in [I-D.ietf-nfsv4-rfc5666bis].
The server MUST post buffers large enough Read chunk to receive supply opaque file data for a
WRITE operation or the largest
possible incoming message (approximately 12 KB pathname for a CREATE(NF4LNK) operation in an
NFS version 2, or
36 KB for 4 COMPOUND procedure. An NFS client MUST NOT send a Read
chunk that corresponds with any other XDR data item in any other NFS
version 3, would be vastly sufficient), and the 4 operation.

Similarly, an NFS client
can post buffers large enough MAY provide a Write chunk to receive replies based on the "rsize"
it is using to the server, plus either
opaque file data from a fixed overhead for READ operation, NFS4_CONTENT_DATA from a
READ_PLUS operation, or the RPC and pathname from a READLINK operation in an
NFS
headers. Because the server version 4 COMPOUND procedure. An NFS client MUST NOT return provide a
Write chunk that corresponds with any other XDR data item in excess of this
size, the client can be assured of the adequacy of its posted buffer
sizes.

Flow control is handled dynamically by the RPC RDMA protocol, and
write padding any
other NFS version 4 operation.

There is OPTIONAL no prohibition against an NFS version 4 COMPOUND procedure
constructed with both a READ and therefore MAY remain unused.

Alternatively, if the server WRITE operation, say. Thus it is administratively configured to values
appropriate
possible for all its clients, the same assurance of
interoperability within the domain can be made.

The NFS version 4 COMPOUND procedures to use of a configuration protocol with both the Read
list and Write list simultaneously. An NFS v2 client MAY provide a Read
list and v3 is therefore
OPTIONAL. Employing a configuration exchange may allow some
advantage to server resource management through accurately sizing
buffers, enabling Write list in the server same transaction if it is sending a Long
Call or Reply.

Some remarks need to know exactly how many RDMA Reads may be in progress at once on the client connection, made about how NFS version 4 clients estimate
reply size, and enabling client
write padding, which may be desirable for certain servers when RDMA
Read is impractical.

5. how DDP-eligibility violations are reported.

4.1. NFS Version 4 Mapping

This specification applies to the first minor version of COMPOUND Considerations

An NFS version 4 (NFSv4.0) and any subsequent minor versions that do not override
this mapping.

The Write list MUST be considered only for the COMPOUND procedure.
This procedure returns results from supplies arguments for a sequence
of operations. Only
the opaque file data operations, and returns results from that sequence. A client MAY
construct an NFS READ operation and the pathname from
a READLINK operation MUST utilize entries from the Write list.

If there is no Write list, i.e., version 4 COMPOUND procedure that uses more than one
chunk in either the Read list is null, then any READ or
READLINK operations in the COMPOUND MUST return their data inline. Write list. The NFSv4.0 NFS client MUST ensure provides
XDR Position values in this case that any result of its
READ each Read chunk to disambiguate which chunk is
associated with which XDR data item.

However NFS server and READLINK requests will fit within its receive buffers, client implementations must agree in
order advance
on how to avoid a resulting RDMA transport error upon transfer. pair Write chunks with returned result data items. The
server
mechanism specified in [I-D.ietf-nfsv4-rfc5666bis]) is not required to detect this. applied here:

o The first entry chunk in the Write list MUST be used by the first READ
or READLINK operation in the an NFS version 4 COMPOUND request. procedure. The
next Write list entry chunk is used by the next READ or READLINK, and so on.

o If there are more READ or READLINK operations than Write list entries, chunks,
then any remaining operations MUST return their results inline.

o If an NFS client presents a Write list entry is presented, chunk, then the corresponding
READ or READLINK operation MUST return its data via an RDMA Write to the buffer
indicated by the Write list entry. placing data
into that chunk.

o If the Write list entry chunk has zero RDMA segments, or if the total size of
the segments is zero, then the corresponding READ or READLINK
operation MUST return its result inline.

The following example shows an RDMA a Write list with three posted
buffers Write chunks, A,
B, and C. The server consumes the provided Write chunks by writing
the results of the designated operations in the compound request,
READ and READLINK, consume the posted buffers by writing
their results back to each buffer.

RDMA chunk.

Write list:

A --> B --> C

Compound

NFS version 4 COMPOUND request:

PUTFH LOOKUP READ PUTFH LOOKUP READLINK PUTFH LOOKUP READ
| | |
v v v
A B C

If the client does not want to have the READLINK result returned
directly, then it provides a zero-length array of segment triplets for
buffer B or sets the values in the segment triplet for buffer B to
zeros so to indicate that the READLINK result MUST must be returned inline.

The situation is similar for RDMA Read lists sent by the client and
applies to the NFSv4.0 WRITE and SYMLINK procedures as for v3.
Additionally, inline segments too large to fit in posted buffers MAY
be transferred in special "RDMA_NOMSG" messages.

Non-RDMA (inline) WRITE transfers MAY OPTIONALLY employ the
"RDMA_MSGP" padding method described in the RPC-over-RDMA protocol,
if the appropriate value for the server is known to the client.
Padding allows the opaque file data to arrive at the server in an
aligned fashion, which may improve server performance. In order to
ensure accurate alignment for all data, it is likely that the client
will restrict its use of OPTIONAL padding to COMPOUND requests
containing only a single WRITE operation.

Unlike NFS versions 2 and 3, the maximum size of an NFS version 4
COMPOUND is not bounded, even when RDMA chunks are in use. While it
might appear that a configuration protocol exchange (such as the one
described in [I-D.ietf-nfsv4-rfc5666bis]) would help, in fact the
layering issues involved in building COMPOUNDs by NFS make such a
mechanism unworkable. bounded. However, typical NFS version 4 clients
rarely issue such problematic requests. In practice, they behave in much more predictable ways, in
fact most still support the traditional rsize/wsize mount parameters.
Therefore, most NFS version 4
clients function over RPC-over-RDMA behave in
the same way as NFS versions 2 and 3, operationally.

There are however advantages to allowing both client much more predictable ways. Rsize and server to
operate with prearranged size constraints, for example, use of the
sizes wsize apply
to better manage COMPOUND operations by capping the server's response cache. total amount of data payload
allowed in each COMPOUND. An extension to NFS version 4 supporting a more
comprehensive exchange of upper-layer message size parameters is part
of [RFC5661].

5.1.

4.2. NFS Version 4 Callbacks

The NFS version 4 protocols support server-initiated callbacks to
selected clients, in order to
notify them clients of events such as recalled
delegations, etc. These callbacks present delegations. There are no particular issue to
being framed over RPC-over-RDMA since such callbacks do not carry
bulk
DDP-eligible data such as NFS READ or NFS WRITE. They MAY be transmitted
inline via RDMA_MSG, or if the items in callback message protocols associated with
NFSv4.0, NFSv4.1, or its reply overflow
the negotiated buffer sizes for a callback connection, they MAY be
transferred via the RDMA_NOMSG method as described above for other
exchanges.

One special case is noteworthy: in NFSv4.2.

In NFS version 4.1, the 4.1 and 4.2, callback
channel is optionally negotiated to be operations may appear on the
same connection as one used for NFS version 4 client requests. In this case, and because the transaction
ID (XID) is present in the RPC-over-RDMA header, the client MUST
ascertain whether the message is in fact an RPC REPLY, and therefore
a reply to a prior request and carrying its XID, before processing it
as such. By the same token, the server MUST ascertain whether an
incoming message To
operate on such a callback-eligible connection is an RPC
CALL, before optionally processing the XID.

In the callback case, the XID present in the RPC-over-RDMA header
will potentially have any value, which may (or may not) collide with
an XID used by the client for a previous or future request. The
client and server MUST inspect the RPC component of the message to
determine its potential disposition as either an RPC CALL or RPC
REPLY, prior to processing this XID, transports, NFS version 4 clients and
servers MUST NOT reject or accept it
without also determining use the proper context.

6. mechanism described in
[I-D.ietf-nfsv4-rpcrdma-bidirection].

5. IANA Considerations

NFS use of direct data placement introduces a need for an additional
NFS port number assignment for networks that share traditional UDP
and TCP port spaces with RDMA services. The iWARP [RFC5041]
[RFC5040] protocol is such an example (InfiniBand is not).

NFS servers for versions 2 and 3 [RFC1094] [RFC1813] traditionally
listen for clients on UDP and TCP port 2049, and additionally, they
register these with the portmapper and/or rpcbind [RFC1833] service.
However, [RFC7530] requires NFS servers for version 4 to listen on
TCP port 2049, and they are not required to register.

An NFS version 2 or version 3 server supporting RPC-over-RDMA on such
a network and registering itself with the RPC portmapper MAY choose
an arbitrary port, or MAY use the alternative well-known port number
for its RPC-over-RDMA service. The chosen port MAY be registered
with the RPC portmapper under the netid assigned by the requirement
in [I-D.ietf-nfsv4-rfc5666bis].

An NFS version 4 server supporting RPC-over-RDMA on such a network
MUST use the alternative well-known port number for its RPC-over-RDMA
service. Clients SHOULD connect to this well-known port without
consulting the RPC portmapper (as for NFSv4/TCP).

The port number assigned to an NFS service over an RPC-over-RDMA
transport is available from the IANA port registry [RFC3232].

6. Security Considerations

The RDMA transport for RPC [I-D.ietf-nfsv4-rfc5666bis] supports all
RPC [RFC5531] security models, including RPCSEC_GSS [RFC2203]
security and link- level transport-level security. The choice of RDMA Read and
RDMA Write to return convey RPC argument and results, respectively, results does not affect this,
since it only changes the method of data transfer. Specifically, the
requirements of [I-D.ietf-nfsv4-rfc5666bis] ensure that this choice
does not introduce new vulnerabilities.

Because this document defines only the binding of the NFS protocols
atop [I-D.ietf-nfsv4-rfc5666bis], all relevant security
considerations are therefore to be described at that layer.

7. Acknowledgments

The author gratefully acknowledges the work of Brent Callaghan and
Tom Talpey on the original NFS Direct Data Placement specification
[RFC5667]. The author also wishes to thank Bill Baker and Greg
Marsden for their support of this work.

Dave Noveck provided excellent review, constructive suggestions, and
consistent navigational guidance throughout the process of drafting
this document.

Special thanks go to nfsv4 Working Group Chair Spencer Shepler and
nfsv4 Working Group Secretary Thomas Haynes for their support.

8. References

9.1.

8.1. Normative References

[I-D.ietf-nfsv4-minorversion2]
Haynes, T., "NFS Version 4 Minor Version 2", draft-ietf-
nfsv4-minorversion2-41 (work in progress), January 2016.

[I-D.ietf-nfsv4-rfc5666bis]
Lever, C., Simpson, W., and T. Talpey, "Remote Direct
Memory Access Transport for Remote Procedure Call, Version
One", draft-ietf-nfsv4-rfc5666bis-07 (work in progress),
May 2016.

[I-D.ietf-nfsv4-rpcrdma-bidirection]
Lever, C., "Bi-directional Remote Procedure Call On RPC-
over-RDMA Transports", draft-ietf-nfsv4-rpcrdma-
bidirection-05 (work in progress), June 2016.

[RFC1833] Srinivasan, R., "Binding Protocols for ONC RPC Version 2",
RFC 1833, DOI 10.17487/RFC1833, August 1995,
<http://www.rfc-editor.org/info/rfc1833>.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/
RFC2119, 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.

[RFC2203] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol
Specification", RFC 2203, DOI 10.17487/RFC2203, September
1997, <http://www.rfc-editor.org/info/rfc2203>.

[RFC5531] Thurlow, R., "RPC: Remote Procedure Call Protocol
Specification Version 2", RFC 5531, DOI 10.17487/RFC5531,
May 2009, <http://www.rfc-editor.org/info/rfc5531>.

[RFC5661] Shepler, S., Ed., Eisler, M., Ed., and D. Noveck, Ed.,
"Network File System (NFS) Version 4 Minor Version 1
Protocol", RFC 5661, DOI 10.17487/RFC5661, January 2010,
<http://www.rfc-editor.org/info/rfc5661>.

[RFC7530] Haynes, T., Ed. and D. Noveck, Ed., "Network File System
(NFS) Version 4 Protocol", RFC 7530, DOI 10.17487/RFC7530,
March 2015, <http://www.rfc-editor.org/info/rfc7530>.

9.2.

8.2. Informative References

[RFC1094] Nowicki, B., "NFS: Network File System Protocol
specification", RFC 1094, DOI 10.17487/RFC1094, March
1989, <http://www.rfc-editor.org/info/rfc1094>.

[RFC1813] Callaghan, B., Pawlowski, B., and P. Staubach, "NFS
Version 3 Protocol Specification", RFC 1813,
DOI 10.17487/
RFC1813, 10.17487/RFC1813, June 1995,
<http://www.rfc-editor.org/info/rfc1813>.

[RFC3232] Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced
by an On-line Database", RFC 3232, DOI 10.17487/RFC3232,
January 2002, <http://www.rfc-editor.org/info/rfc3232>.

[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, <http://www.rfc-editor.org/info/rfc5040>.

[RFC5041] Shah, H., Pinkerton, J., Recio, R., and P. Culley, "Direct
Data Placement over Reliable Transports", RFC 5041,
DOI 10.17487/RFC5041, October 2007,
<http://www.rfc-editor.org/info/rfc5041>.

[RFC5666] Talpey, T. and B. Callaghan, "Remote Direct Memory Access
Transport for Remote Procedure Call", RFC 5666, DOI
10.17487/RFC5666, January 2010,
<http://www.rfc-editor.org/info/rfc5666>.

[RFC5667] Talpey, T. and B. Callaghan, "Network File System (NFS)
Direct Data Placement", RFC 5667, DOI 10.17487/RFC5667,
January 2010, <http://www.rfc-editor.org/info/rfc5667>.

Author's Address

Charles Lever (editor)
Oracle Corporation
1015 Granger Avenue
Ann Arbor, MI 48104
USA

Phone: +1 734 274 2396
Email: chuck.lever@oracle.com