RDMA Connection Manager Private Data For RPC-Over-RDMA Version 1
draft-ietf-nfsv4-rpcrdma-cm-pvt-data-04

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Network File System Version 4                                   C. Lever
Internet-Draft                                                    Oracle
Intended status: Informational                             June 13, 2019
Expires: December 15, 2019

    RDMA Connection Manager Private Data For RPC-Over-RDMA Version 1
                draft-ietf-nfsv4-rpcrdma-cm-pvt-data-04

Abstract

   This document specifies the format of RDMA-CM Private Data exchanged
   between RPC-over-RDMA version 1 peers as part of establishing a
   connection.  Such private data is used to indicate peer support for
   remote invalidation and larger-than-default inline thresholds.  The
   addition of the private data payload specified in this document is an
   OPTIONAL extension.  The RPC-over-RDMA version 1 protocol does not
   require the payload to be present.

Status of This Memo

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

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   This Internet-Draft will expire on December 15, 2019.

Copyright Notice

   Copyright (c) 2019 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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of

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Internet-Draft        RPC-Over-RDMA CM Private Data            June 2019

   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Advertised Transport Properties . . . . . . . . . . . . . . .   3
     3.1.  Inline Threshold Size . . . . . . . . . . . . . . . . . .   3
     3.2.  Remote Invalidation . . . . . . . . . . . . . . . . . . .   4
   4.  Private Data Message Format . . . . . . . . . . . . . . . . .   5
     4.1.  Interoperability Considerations . . . . . . . . . . . . .   6
   5.  Updating the Message Format . . . . . . . . . . . . . . . . .   7
     5.1.  Feature Support Flags . . . . . . . . . . . . . . . . . .   7
     5.2.  Inline Threshold Values . . . . . . . . . . . . . . . . .   8
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  10
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   The RPC-over-RDMA version 1 transport protocol [RFC8166] enables
   payload data transfer using Remote Direct Memory Access (RDMA) for
   upper layer protocols based on Remote Procedure Calls (RPC)
   [RFC5531].  The terms "Remote Direct Memory Access" (RDMA) and
   "Direct Data Placement" (DDP) are introduced in [RFC5040].

   The two most immediate shortcomings of RPC-over-RDMA version 1 are:

   o  Setting up an RDMA data transfer (via RDMA Read or Write) can be
      costly.  The small default size of messages transmitted using RDMA
      Send forces the use of RDMA Read or Write operations even for
      relatively small messages and data payloads.
      The original specification of RPC-over-RDMA version 1 provided an
      out-of-band protocol for passing inline threshold values between
      connected peers [RFC5666].  However, [RFC8166] eliminated support
      for this protocol making it unavailable for this purpose.

   o  Unlike most other contemporary RDMA-enabled storage protocols,
      there is no facility in RPC-over-RDMA version 1 that enables the
      use of remote invalidation [RFC5042].

   RPC-over-RDMA version 1 has no means of extending its XDR definition
   in such a way that interoperability with existing implementations is

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