Network File System Version 4                              C. Lever, Ed.
Internet-Draft                                                    Oracle
Intended status: Standards Track                               D. Noveck
Expires: October 10, 2016                                            HPE
                                                           April 8, 2016


                       RPC-over-RDMA Version Two
                 draft-cel-nfsv4-rpcrdma-version-two-00

Abstract

   This document specifies an improved protocol for conveying Remote
   Procedure Call (RPC) messages on physical transports capable of
   Remote Direct Memory Access (RDMA), based on RPC-over-RDMA Version
   One.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 10, 2016.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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



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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Inline Threshold  . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Motivation  . . . . . . . . . . . . . . . . . . . . . . .   4
     2.3.  Default Values  . . . . . . . . . . . . . . . . . . . . .   4
   3.  Protocol Extensibility  . . . . . . . . . . . . . . . . . . .   5
     3.1.  Optional Features . . . . . . . . . . . . . . . . . . . .   5
     3.2.  Documentation Requirements  . . . . . . . . . . . . . . .   5
   4.  XDR Protocol Definition . . . . . . . . . . . . . . . . . . .   6
     4.1.  Code Component License  . . . . . . . . . . . . . . . . .   7
     4.2.  RPC-Over-RDMA Version Two XDR . . . . . . . . . . . . . .   9
   5.  Protocol Version Negotiation  . . . . . . . . . . . . . . . .  11
     5.1.  Responder Does Support RPC-over-RDMA Version Two  . . . .  11
     5.2.  Responder Does Not Support RPC-over-RDMA Version Two  . .  12
     5.3.  Requester Does Not Support RPC-over-RDMA Version Two  . .  12
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  13
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  13
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Remote Direct Memory Access (RDMA) [RFC5040] [RFC5041] [IB] is a
   technique for moving data efficiently between end nodes.  By
   directing data into destination buffers as it is sent on a network,
   and placing it via direct memory access by hardware, the benefits of
   faster transfers and reduced host overhead are obtained.

   A protocol already exists that enables RPC [RFC5531] messages to be
   conveyed on RDMA transports.  That protocol is RPC-over-RDMA Version
   One, specified in [I-D.ietf-nfsv4-rfc5666bis].  RPC-over-RDMA Version
   One is deployed and in use, though there are some shortcomings to
   this protocol, such as:

   o  The use of small Receive buffers force the use of RDMA Read and
      Write transfers for small payloads, and limit the size of
      backchannel messages

   o  Lack of support for potential optimizations, such as remote
      invalidation, that require changes to on-the-wire behavior





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   To address these issues in a way that is compatible with existing
   RPC-over-RDMA Version One deployments, a new version of RPC-over-RDMA
   is presented in this document.  RPC-over-RDMA Version Two contains
   only incremental changes over RPC-over-RDMA Version One to facilitate
   adoption of Version Two by existing Version One implementations.

   The major new feature in RPC-over-RDMA Version Two is extensibility
   of the RPC-over-RDMA header.  Extensibility enables narrow changes to
   RPC-over-RDMA Version Two so that new optional capabilities can be
   introduced without a protocol version change and while maintaining
   interoperability with existing implementations.  New capabilities can
   be proposed and developed independently of each other, and
   implementaters can choose among them.  It should be straightforward
   to create and document experimental features and then bring them
   through the standards process.

   In addition to extensibility, the default inline threshold value is
   larger in RPC-over-RDMA Version Two.  This change is driven by the
   increase in average size of RPC messages containing common NFS
   operations.  With NFSv4.1 [RFC5661] and later, compound operations
   convey more data per RPC message.  The default 1KB inline threshold
   in RPC-over-RDMA Version One prevents attaining the best possible
   performance.

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].

2.  Inline Threshold

2.1.  Terminology

   The term "inline threshold" is defined in Section 4 of
   [I-D.ietf-nfsv4-rfc5666bis].  A receiver's "inline threshold" value
   is the largest message size (in octets) that the receiver can accept
   via an RDMA Receive operation.  Each connection has two inline
   threshold values, one for each peer receiver.  Inline threshold
   values are not advertised to peers via the base RPC-over-RDMA Version
   Two protocol.

   A connection's inline threshold determines when full RDMA Read or
   Write operations are required because the RPC message to be send is
   larger than the peer's Receive buffer.  If an RPC message does not
   contain DDP-eligible data items, a requester prepares a Long Call or
   Reply to convey the whole RPC message using an RDMA Read or Write.




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2.2.  Motivation

   RDMA Read and Write operations require that each data payload resides
   in a region of memory that is registered with the RNIC.  When an RPC
   is complete, that region is unregistered, fencing it from the
   responder.

   Both registration and unregistration have a latency cost which is
   insignificant compared to data handling costs.  When a data payload
   is small, however, the cost of registering and unregistering the
   memory where it resides becomes a relatively significant part of
   total RPC latency.  Therefore the most efficient operation of RPC-
   over-RDMA occurs when RDMA Read and Write operations are used for
   large payloads, and avoided for small payloads.

   When RPC-over-RDMA Version One was conceived, the typical size of RPC
   messages that did not involve a significant data payload was under
   500 bytes.  A 1024-byte inline threshold adequately minimized the
   frequency of inefficient Long Calls and Replies.

   Starting with NFSv4.1 [RFC5661], NFS COMPOUND RPC messages are larger
   and more complex than before.  With a 1024-byte inline threshold,
   RDMA Read or Write operations are needed for frequent operations that
   do not bear a data payload, such as GETATTR and LOOKUP, reducing the
   efficiency of the transport.  To reduce the need to use Long Calls
   and Replies, RPC-over-RDMA Version Two quadruples the default inline
   threshold size.  This also increases the maximum size of backward
   direction RPC messages.

2.3.  Default Values

   RPC-over-RDMA Version Two receiver implementations MUST support an
   inline threshold of 4096 bytes, but MAY support larger inline
   threshold values.  A mechanism for discovering a peer's preferred
   inline threshold value may be used to optimize RDMA Send operations
   further.  In the absense of such a mechanism, senders MUST assume a
   receiver's inline threshold is 4096 bytes.

   The new default inline threshold size is no larger than the size of a
   hardware page on typical platforms.  This conserves the resources
   needed to Send and Receive base level RPC-over-RDMA Version Two
   messages, enabling RPC-over-RDMA Version Two to be used on a broad
   base of hardware.








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3.  Protocol Extensibility

   The core RPC-over-RDMA Version Two header format is specified in
   Section 4 as a complete and stand-alone piece of XDR.  Any change to
   this XDR description requires a protocol version number change.

3.1.  Optional Features

   RPC-over-RDMA Version Two introduces the ability to extend the core
   protocol via optional features.  Extensibility enables minor protocol
   issues to be addressed and incremental enhancements to be made
   without the need to change the protocol version.  The key capability
   is that both sides can detect whether a feature is supported by their
   peer or not.  With this ability, OPTIONAL features can be introduced
   over time to an otherwise stable protocol.

   The rdma_opttype field carries a 32-bit unsigned integer.  The value
   in this field denotes an optional operation that MAY be supported by
   the receiver.  The values of this field and their meaning are defined
   in other Standards Track documents.

   The rdma_optinfo field carries opaque data.  The content of this
   field is data meaningful to the optional operation denoted by the
   value in rdma_opttype.  The content of this field is not defined in
   the base RPC-over-RDMA Version Two protocol, but is defined in other
   Standards Track documents

   When an implementation does not recognize or support the value
   contained in the rdma_opttype field, it MUST send an RPC-over-RDMA
   message with the rdma_xid field set to the same value as the
   erroneous message, the rdma_proc field set to RDMA_ERROR, and the
   rdma_err field set to RDMA_ERR_INVAL_OPTION.

3.2.  Documentation Requirements

   RPC-over-RDMA Version Two may be extended by defining a new
   rdma_opttype value and XDR description of the corresponding
   rdma_optinfo content.

   A set of such new protocol elements may be introduced by a Standards
   Track document and are together considered an OPTIONAL feature.
   nfsv4 Working Group and IESG review, together with appropriate
   testing of prototype implementations, should ensure continued
   interoperation with existing implementations.

   Documents describing extensions to RPC-over-RDMA Version Two should
   contain:




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   o  An explanation of the purpose and use of each new protocol element
      added

   o  An XDR description and a script to extract it

   o  A mechanism for reporting errors to the message sender that are
      outside the available choices in the base RPC-over-RDMA Version
      Two protocol

   o  A requirement that an RPC Payload Stream MUST or MUST NOT follow
      the Transport Header Stream for each new opttype code added

   o  A description of interactions with existing features (e.g.,
      requirements that another OPTIONAL feature needs to be present and
      supported for newly added features to work)

   Implementers concatenate the XDR description of the new feature with
   the XDR description of the base protocol, extracted from this
   document, to produce a combined XDR description for the RPC-over-RDMA
   Version Two protocol with the specified extension.

4.  XDR Protocol Definition

   This section contains a description of the core features of the RPC-
   over-RDMA Version Two protocol, expressed in the XDR language
   [RFC4506].

   This description is provided in a way that makes it simple to extract
   into ready-to-compile form.  The reader can apply the following shell
   script to this document to produce a machine-readable XDR description
   of the RPC-over-RDMA Version One protocol without any OPTIONAL
   extensions.


   <CODE BEGINS>

   #!/bin/sh
   grep '^ *///' | sed 's?^ /// ??' | sed 's?^ *///$??'

   <CODE ENDS>


   That is, if the above script is stored in a file called "extract.sh"
   and this document is in a file called "spec.txt" then the reader can
   do the following to extract an XDR description file:






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   <CODE BEGINS>

   sh extract.sh < spec.txt > rpcrdma_corev2.x

   <CODE ENDS>


   Optional extensions to RPC-over-RDMA Version Two, published as
   Standards Track documents, will have similar means of providing XDR
   that describes those extensions.  Once XDR for all desired extensions
   is also extracted, it can be appended to the XDR description file
   extracted from this document to produce a consolidated XDR
   description file reflecting all extensions selected for an RPC-over-
   RDMA implementation.

4.1.  Code Component License

   Code components extracted from this document must include the
   following license text.  When the extracted XDR code is combined with
   other complementary XDR code which itself has an identical license,
   only a single copy of the license text need be preserved.






























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   <CODE BEGINS>

   /// /*
   ///  * Copyright (c) 2010, 2016 IETF Trust and the persons
   ///  * identified as authors of the code.  All rights reserved.
   ///  *
   ///  * The authors of the code are:
   ///  * B. Callaghan, T. Talpey, C. Lever, and D. Noveck.
   ///  *
   ///  * Redistribution and use in source and binary forms, with
   ///  * or without modification, are permitted provided that the
   ///  * following conditions are met:
   ///  *
   ///  * - Redistributions of source code must retain the above
   ///  *   copyright notice, this list of conditions and the
   ///  *   following disclaimer.
   ///  *
   ///  * - Redistributions in binary form must reproduce the above
   ///  *   copyright notice, this list of conditions and the
   ///  *   following disclaimer in the documentation and/or other
   ///  *   materials provided with the distribution.
   ///  *
   ///  * - Neither the name of Internet Society, IETF or IETF
   ///  *   Trust, nor the names of specific contributors, may be
   ///  *   used to endorse or promote products derived from this
   ///  *   software without specific prior written permission.
   ///  *
   ///  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS
   ///  *   AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
   ///  *   WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   ///  *   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   ///  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
   ///  *   EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
   ///  *   LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   ///  *   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   ///  *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   ///  *   SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   ///  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   ///  *   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   ///  *   OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
   ///  *   IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
   ///  *   ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   ///  */

   <CODE ENDS>






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4.2.  RPC-Over-RDMA Version Two XDR

   The XDR defined in this section is used to encode the Transport
   Header Stream in each RPC-over-RDMA Version Two message.  The terms
   "Transport Header Stream" and "RPC Payload Stream" are defined in
   Section 4 of [I-D.ietf-nfsv4-rfc5666bis].


   <CODE BEGINS>

   /// struct rpcrdma2_segment {
   ///         uint32 rdma_handle;
   ///         uint32 rdma_length;
   ///         uint64 rdma_offset;
   /// };
   ///
   /// struct rpcrdma2_read_segment {
   ///         uint32                  rdma_position;
   ///         struct rpcrdma2_segment rdma_target;
   /// };
   ///
   /// struct rpcrdma2_read_list {
   ///         struct rpcrdma2_read_segment rdma_entry;
   ///         struct rpcrdma2_read_list    *rdma_next;
   /// };
   ///
   /// struct rpcrdma2_write_chunk {
   ///         struct rpcrdma2_segment rdma_target<>;
   /// };
   ///
   /// struct rpcrdma2_write_list {
   ///         struct rpcrdma2_write_chunk rdma_entry;
   ///         struct rpcrdma2_write_list  *rdma_next;
   /// };
   ///
   /// struct rpcrdma2_chunk_lists {
   ///         struct rpcrdma2_read_list   *rdma_reads;
   ///         struct rpcrdma2_write_list  *rdma_writes;
   ///         struct rpcrdma2_write_chunk *rdma_reply;
   /// };
   ///
   /// enum rpcrdma2_errcode {
   ///         RDMA_ERR_VERS = 1,
   ///         RDMA_ERR_BAD_HEADER = 2,
   ///         RDMA_ERR_INVAL_OPTION = 3
   /// };
   ///
   /// struct rpcrdma2_err_vers {



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   ///         uint32 rdma_vers_low;
   ///         uint32 rdma_vers_high;
   /// };
   ///
   /// union rpcrdma2_error switch (rpcrdma2_errcode rdma_err) {
   ///         case RDMA_ERR_VERS:
   ///           rpcrdma2_err_vers rdma_vrange;
   ///         case RDMA_ERR_BAD_HEADER:
   ///           void;
   ///         case RDMA_ERR_INVAL_OPTION:
   ///           void;
   /// };
   ///
   /// struct rpcrdma2_optional {
   ///         uint32 rdma_opttype;
   ///         opaque rdma_optinfo<>;
   /// };
   ///
   /// enum rpcrdma2_proc {
   ///         RDMA_MSG = 0,
   ///         RDMA_NOMSG = 1,
   ///         RDMA_MSGP = 2,  /* Reserved */
   ///         RDMA_DONE = 3,  /* Reserved */
   ///         RDMA_ERROR = 4,
   ///         RDMA_OPTIONAL = 5
   /// };
   ///
   /// union rpcrdma2_body switch (rpcrdma2_proc rdma_proc) {
   ///         case RDMA_MSG:
   ///           rpcrdma2_chunks rdma_chunks;
   ///         case RDMA_NOMSG:
   ///           rpcrdma2_chunks rdma_chunks;
   ///         case RDMA_MSGP:
   ///           void;
   ///         case RDMA_DONE:
   ///           void;
   ///         case RDMA_ERROR:
   ///           rpcrdma2_error rdma_error;
   ///         case RDMA_OPTIONAL:
   ///           rpcrdma2_optional rdma_optional;
   /// };
   ///
   /// struct rpcrdma2_xprt_hdr {
   ///         uint32        rdma_xid;
   ///         uint32        rdma_vers;
   ///         uint32        rdma_credit;
   ///         rpcrdma2_body rdma_body;
   /// };



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   <CODE ENDS>


   When the rdma_proc field has the value RDMA_MSG, an RPC Payload
   Stream MUST follow the Transport Header Stream in the Send buffer.
   When the rdma_proc field has the value RDMA_OPTIONAL, an RPC Payload
   Stream MAY follow the Transport header Stream in the Send buffer.
   When the rdma_proc field has any other value, an RPC Payload Stream
   MUST NOT follow the Transport Header Stream.

   Implementations of RPC-over-RDMA Version Two are REQUIRED to support
   backwards direction operation as described in
   [I-D.ietf-nfsv4-rpcrdma-bidirection].

   Error handling works the same way in RPC-over-RDMA Version Two as it
   does in RPC-over-RDMA Version One, with one change described in
   Section 3.1.  Version One error handling is described in Section 5 of
   [I-D.ietf-nfsv4-rfc5666bis].

5.  Protocol Version Negotiation

   When an RPC-over-RDMA Version Two requester establishes a connection
   to a responder, the first order of business is to determine the
   responder's highest supported protocol version.

   As with RPC-over-RDMA Version One, a requester MUST assume the
   ability to exchange only a single RPC-over-RDMA message at a time
   until it receives a non-error RPC-over-RDMA message from the
   responder that reports the responder's actual credit limit.

   First, the requester sends a single valid RPC-over-RDMA message with
   the value two (2) in the rdma_vers field.  Because the responder
   might support only RPC-over-RDMA Version One, this initial message
   can be no larger than the Version One default inline threshold of
   1024 bytes.

5.1.  Responder Does Support RPC-over-RDMA Version Two

   If the responder does support RPC-over-RDMA Version Two, it sends an
   RPC-over-RDMA message back to the requester with the same XID
   containing a valid non-error response.  Subsequently, both peers use
   the default inline threshold value for RPC-over-RDMA Version Two
   connections (4096 bytes).








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5.2.  Responder Does Not Support RPC-over-RDMA Version Two

   If the responder does not support RPC-over-RDMA Version Two,
   [I-D.ietf-nfsv4-rfc5666bis] REQUIRES that it send an RPC-over-RDMA
   message to the requester with the same XID, with RDMA_ERROR in the
   rdma_proc field, and with the error code RDMA_ERR_VERS.  This message
   also reports a range of protocol versions that the responder
   supports.  To continue operation, the requester selects a protocol
   version in the range of responder-supported versions for subsequent
   messages on this connection.

   If the connection is lost immediately after the RDMA_ERROR reply is
   received, a requester can avoid a possible version negotiation loop
   when re-establishing another connection by assuming that particular
   responder does not support RPC-over-RDMA Version Two.  A requester
   can assume the same situation (no responder support for RPC-over-RDMA
   Version Two) if the initial negotiation message is lost or dropped.

   Once the negotiation exchange is complete, both peers use the default
   inline threshold value for the protocol version that will be used for
   the remainder of the connection lifetime.  To permit inline threshold
   values to change during negotiation of protocol version, RPC-over-
   RDMA Version Two implementations MUST allow inline threshold values
   to change without triggering a connection loss.

5.3.  Requester Does Not Support RPC-over-RDMA Version Two

   [I-D.ietf-nfsv4-rfc5666bis] REQUIRES that a responder MUST send
   Replies with the same RPC-over-RDMA protocol version that the
   requester uses to send its Calls.

6.  Security Considerations

   The security considerations for RPC-over-RDMA Version Two are the
   same as those for RPC-over-RDMA Version One.

7.  IANA Considerations

   There are no IANA considerations at this time.

8.  Acknowledgments

   The authors gratefully acknowledge the work of Brent Callaghan and
   Tom Talpey on the original RPC-over-RDMA Version One specification
   [RFC5666].  The authors also wish to thank Bill Baker, Greg Marsden,
   and Matt Benjamin for their support of this work.





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   The extract.sh shell script and formatting conventions were first
   described by the authors of the NFSv4.1 XDR specification [RFC5662].

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

9.  References

9.1.  Normative References

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

   [RFC4506]  Eisler, M., Ed., "XDR: External Data Representation
              Standard", STD 67, RFC 4506, DOI 10.17487/RFC4506, May
              2006, <http://www.rfc-editor.org/info/rfc4506>.

   [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>.

9.2.  Informative References

   [I-D.ietf-nfsv4-rfc5666bis]
              Lever, C., Simpson, W., and T. Talpey, "Remote Direct
              Memory Access Transport for Remote Procedure Call", draft-
              ietf-nfsv4-rfc5666bis-04 (work in progress), March 2016.

   [I-D.ietf-nfsv4-rpcrdma-bidirection]
              Lever, C., "Size-Limited Bi-directional Remote Procedure
              Call On Remote Direct Memory Access Transports", draft-
              ietf-nfsv4-rpcrdma-bidirection-01 (work in progress),
              September 2015.

   [IB]       InfiniBand Trade Association, "InfiniBand Architecture
              Specifications", <http://www.infinibandta.org>.

   [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>.



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Internet-Draft          RDMA Transport for RPC V2             April 2016


   [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>.

   [RFC5662]  Shepler, S., Ed., Eisler, M., Ed., and D. Noveck, Ed.,
              "Network File System (NFS) Version 4 Minor Version 1
              External Data Representation Standard (XDR) Description",
              RFC 5662, DOI 10.17487/RFC5662, January 2010,
              <http://www.rfc-editor.org/info/rfc5662>.

   [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>.

Authors' Addresses

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

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


   David Noveck
   Hewlett Packard Enterprise
   165 Dascomb Road
   Andover, MA  01810
   USA

   Phone: +1 978 474 2011
   Email: davenoveck@gmail.com















Lever & Noveck          Expires October 10, 2016               [Page 14]