Bi-directional Remote Procedure Call On RPC-over-RDMA Transports
draft-ietf-nfsv4-rpcrdma-bidirection-06

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Last updated 2017-02-07 (latest revision 2017-01-20)
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Network File System Version 4                                   C. Lever
Internet-Draft                                                    Oracle
Intended status: Standards Track                        January 20, 2017
Expires: July 24, 2017

    Bi-directional Remote Procedure Call On RPC-over-RDMA Transports
                draft-ietf-nfsv4-rpcrdma-bidirection-06

Abstract

   Minor versions of NFSv4 newer than NFSv4.0 work best when ONC RPC
   transports can send Remote Procedure Call transactions in both
   directions on the same connection.  This document describes how RPC-
   over-RDMA transport endpoints convey RPCs in both directions on a
   single connection.

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].

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
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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on July 24, 2017.

Copyright Notice

   Copyright (c) 2017 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

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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Understanding RPC Direction . . . . . . . . . . . . . . . . .   2
   3.  Immediate Uses Of Bi-Directional RPC-over-RDMA  . . . . . . .   4
   4.  Flow Control  . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  Sending And Receiving Backward Operations . . . . . . . . . .   8
   6.  In the Absence of Backward Direction Support  . . . . . . . .  10
   7.  Considerations For Upper Layer Bindings . . . . . . . . . . .  11
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  11
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   10. Normative References  . . . . . . . . . . . . . . . . . . . .  12
   Appendix A.  Acknowledgements . . . . . . . . . . . . . . . . . .  12
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   The purpose of this document is to enable concurrent operation in
   both directions on a single transport connection using RPC-over-RDMA
   protocol versions that do not have specific facilities for backward
   direction operation.

   Backward direction RPC transactions are necessary for the operation
   of NFSv4.1, and in particular, of Parallel NFS (pNFS) [RFC5661],
   though any Upper Layer Protocol implementation may make use of them.
   An Upper Layer Binding for NFSv4.x callback operation is additionally
   required (see Section 7), but is not provided in this document.

   For example, using the approach described herein, RPC transactions
   can be conveyed in both directions on the same RPC-over-RDMA Version
   One connection without changes to the XDR description of RPC-over-
   RDMA Version One.  This document does not modify the XDR or protocol
   described in [I-D.ietf-nfsv4-rfc5666bis].  Future versions of RPC-
   over-RDMA may adopt the approach described herein, or may replace it
   with a different approach.

2.  Understanding RPC Direction

   The ONC RPC protocol as described in [RFC5531] is architected as a
   message-passing protocol between one server and one or more clients.
   ONC RPC transactions are made up of two types of messages.

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   A CALL message, or "Call", requests work.  A Call is designated by
   the value CALL in the message's msg_type field.  An arbitrary unique
   value is placed in the message's xid field.  A host that originates a
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