RDMA Connection Manager Private Data For RPC-Over-RDMA Version 1
draft-ietf-nfsv4-rpcrdma-cm-pvt-data-01

Document Type Active Internet-Draft (nfsv4 WG)
Last updated 2018-11-06
Stream IETF
Intended RFC status (None)
Formats plain text xml pdf html bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state I-D Exists
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)
Network File System Version 4                                   C. Lever
Internet-Draft                                                    Oracle
Intended status: Informational                          November 6, 2018
Expires: May 10, 2019

    RDMA Connection Manager Private Data For RPC-Over-RDMA Version 1
                draft-ietf-nfsv4-rpcrdma-cm-pvt-data-01

Abstract

   This document specifies the format of RDMA-CM Private Data exchanged
   between RPC-over-RDMA version 1 peers as a transport connection is
   established.  Such private data is used to indicate peer support for
   remote invalidation and larger-than-default inline thresholds.

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 https://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 May 10, 2019.

Copyright Notice

   Copyright (c) 2018 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
   (https://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.

Lever                     Expires May 10, 2019                  [Page 1]
Internet-Draft        RPC-Over-RDMA CM Private Data        November 2018

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 enables the use of
   RDMA data transfer for upper layer protocols based on RPC [RFC8166].
   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
   preserved.  As a result, an out-of-band mechanism is needed to help
   relieve these constraints for existing RPC-over-RDMA version 1
   implementations.

Lever                     Expires May 10, 2019                  [Page 2]
Internet-Draft        RPC-Over-RDMA CM Private Data        November 2018
Show full document text