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Takeover Suggestion Flag for the ENRP Handle Update Message
draft-dreibholz-rserpool-enrp-takeover-27

Document Type Active Internet-Draft (individual)
Authors Thomas Dreibholz , Xing Zhou
Last updated 2022-03-21
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draft-dreibholz-rserpool-enrp-takeover-27
Network Working Group                                       T. Dreibholz
Internet-Draft                                                 SimulaMet
Intended status: Experimental                                    X. Zhou
Expires: 22 September 2022                             Hainan University
                                                           21 March 2022

      Takeover Suggestion Flag for the ENRP Handle Update Message
               draft-dreibholz-rserpool-enrp-takeover-27

Abstract

   This document describes the Takeover Suggestion Flag for the
   ENRP_HANDLE_UPDATE message of the ENRP protocol.

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 22 September 2022.

Copyright Notice

   Copyright (c) 2022 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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   Please review these documents carefully, as they describe your rights
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.3.  Conventions . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Takeover Suggestion Flag  . . . . . . . . . . . . . . . . . .   3
     2.1.  Definition  . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Reference Implementation  . . . . . . . . . . . . . . . . . .   4
   4.  Testbed Platform  . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     7.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Reliable Server Pooling as described in [3] defines protocols for
   providing highly available services.  The management component used
   for pool administration is denoted as ENRP Server or Pool Registrar
   (PR).  Since a single ENRP server constitutes a single point of
   failure, there must be multiple ENRP servers.  Servers, denoted as
   Pool Elements (PE), use an arbitrary ENRP server for registration
   into the pool.  The chosen ENRP server becomes the Home ENRP Server,
   also denoted as Home PR (PR-H), of the PE.  It is responsible for
   making the PE identity known to the other ENRP servers (by using
   ENRP_HANDLE_UPDATE messages) and also to monitor the PE health (by
   using keep-alive messages).

   As shown in [11], the following scenario leads to unbalanced ENRP
   server workload: consider a set of multiple ENRP servers with one
   subset being unreliable (for example, their network connection has
   problems) and some reliable ENRP servers.  After a while, the
   reliable ENRP server will get the home ENRP server role for almost
   all of the PEs, which results in high workload for this ENRP server.
   Since the home ENRP server role is more computation-intensive (as
   shown by [13]), this leads to highly unbalanced workload for large
   RSerPool setups.  This unbalanced workload remains, even when the
   unreliable ENRP servers become reliable again (for example, when the
   network problems have been solved).

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1.1.  Scope

   The Takeover Suggestion Flag defined in this draft defines a flag for
   the ENRP_HANDLE_UPDATE message.  If the flag is set, the receiving
   ENRP server is suggested to take over the PE specified in the
   ENRP_HANDLE_UPDATE message.

1.2.  Terminology

   The terms are commonly identified in related work and can be found in
   the RSerPool Overview document RFC 5351 [3].

1.3.  Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [1] [2] when, and only when, they appear in all capitals, as shown
   here.

2.  Takeover Suggestion Flag

2.1.  Definition

   In this subsection, only the differences to the ENRP_HANDLE_UPDATE
   message defined in [5] are explained.  The following figure shows the
   ENRP_HANDLE_UPDATE message:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Type = 0x04 |0|0|0|0|0|0|0|T|        Message Length         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                      Sending Server's ID                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Receiving Server's ID                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Update Action          |        (reserved)             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                     Pool Handle Parameter                     :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      :                    Pool Element Parameter                     :
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   T flag: 1 bit (boolean)

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   If set, the receiving ENRP server is suggested to take over the PE
   specified by the Pool Handle and Pool Element Parameters.  It is
   RECOMMENDED for the receiving ENRP server to perform this takeover if
   it has the resources to do so.

3.  Reference Implementation

   The RSerPool reference implementation RSPLIB can be found at [15].
   It supports the functionalities defined by [3], [4], [5], [6] and [8]
   as well as the options [9], [10] and of course the option defined by
   this document.  An introduction to this implementation is provided in
   [12].

4.  Testbed Platform

   A large-scale and realistic Internet testbed platform with support
   for the multi-homing feature of the underlying SCTP protocol is
   NorNet.  A description of NorNet is provided in [14], some further
   information can be found on the project website [16].

5.  Security Considerations

   Security considerations for RSerPool systems are described by [7].

6.  IANA Considerations

   This document does not require additional IANA actions beyond those
   already identified in the ENRP and ASAP protocol specifications.

7.  References

7.1.  Normative References

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

   [2]        Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [3]        Lei, P., Ong, L., Tuexen, M., and T. Dreibholz, "An
              Overview of Reliable Server Pooling Protocols", RFC 5351,
              DOI 10.17487/RFC5351, September 2008,
              <https://www.rfc-editor.org/info/rfc5351>.

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   [4]        Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
              "Aggregate Server Access Protocol (ASAP)", RFC 5352,
              DOI 10.17487/RFC5352, September 2008,
              <https://www.rfc-editor.org/info/rfc5352>.

   [5]        Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A.
              Silverton, "Endpoint Handlespace Redundancy Protocol
              (ENRP)", RFC 5353, DOI 10.17487/RFC5353, September 2008,
              <https://www.rfc-editor.org/info/rfc5353>.

   [6]        Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
              "Aggregate Server Access Protocol (ASAP) and Endpoint
              Handlespace Redundancy Protocol (ENRP) Parameters",
              RFC 5354, DOI 10.17487/RFC5354, September 2008,
              <https://www.rfc-editor.org/info/rfc5354>.

   [7]        Stillman, M., Ed., Gopal, R., Guttman, E., Sengodan, S.,
              and M. Holdrege, "Threats Introduced by Reliable Server
              Pooling (RSerPool) and Requirements for Security in
              Response to Threats", RFC 5355, DOI 10.17487/RFC5355,
              September 2008, <https://www.rfc-editor.org/info/rfc5355>.

   [8]        Dreibholz, T. and M. Tuexen, "Reliable Server Pooling
              Policies", RFC 5356, DOI 10.17487/RFC5356, September 2008,
              <https://www.rfc-editor.org/info/rfc5356>.

   [9]        Dreibholz, T., "Handle Resolution Option for ASAP", Work
              in Progress, Internet-Draft, draft-dreibholz-rserpool-
              asap-hropt-29, 6 September 2021,
              <https://www.ietf.org/archive/id/draft-dreibholz-rserpool-
              asap-hropt-29.txt>.

   [10]       Dreibholz, T. and X. Zhou, "Definition of a Delay
              Measurement Infrastructure and Delay-Sensitive Least-Used
              Policy for Reliable Server Pooling", Work in Progress,
              Internet-Draft, draft-dreibholz-rserpool-delay-28, 6
              September 2021, <https://www.ietf.org/archive/id/draft-
              dreibholz-rserpool-delay-28.txt>.

7.2.  Informative References

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   [11]       Zhou, X., Dreibholz, T., Fa, F., Du, W., and E. P.
              Rathgeb, "Evaluation and Optimization of the Registrar
              Redundancy Handling in Reliable Server Pooling Systems",
              Proceedings of the IEEE 23rd International Conference on
              Advanced Information Networking and
              Applications (AINA) Pages 256-262, ISBN 978-0-7695-3638-5,
              DOI 10.1109/AINA.2009.25, 26 May 2009,
              <https://www.wiwi.uni-due.de/fileadmin/fileupload/I-
              TDR/ReliableServer/Publications/AINA2009.pdf>.

   [12]       Dreibholz, T., "Reliable Server Pooling – Evaluation,
              Optimization and Extension of a Novel IETF Architecture",
              7 March 2007, <https://duepublico.uni-duisburg-
              essen.de/servlets/DerivateServlet/Derivate-16326/
              Dre2006_final.pdf>.

   [13]       Dreibholz, T. and E. P. Rathgeb, "An Evaluation of the
              Pool Maintenance Overhead in Reliable Server Pooling
              Systems", SERSC International Journal on Hybrid
              Information Technology (IJHIT) Number 2, Volume 1, Pages
              17-32, ISSN 1738-9968, April 2008, <https://www.wiwi.uni-
              due.de/fileadmin/fileupload/I-
              TDR/ReliableServer/Publications/IJHIT2008.pdf>.

   [14]       Dreibholz, T. and E. G. Gran, "Design and Implementation
              of the NorNet Core Research Testbed for Multi-Homed
              Systems", Proceedings of the 3nd International Workshop on
              Protocols and Applications with Multi-Homing
              Support (PAMS) Pages 1094-1100, ISBN 978-0-7695-4952-1,
              DOI 10.1109/WAINA.2013.71, 27 March 2013,
              <https://www.simula.no/file/
              threfereedinproceedingsreference2012-12-207643198512pdf/
              download>.

   [15]       Dreibholz, T., "Thomas Dreibholz's RSerPool Page", 2022,
              <https://www.uni-due.de/~be0001/rserpool/>.

   [16]       Dreibholz, T., "NorNet – A Real-World, Large-Scale Multi-
              Homing Testbed", 2022, <https://www.nntb.no/>.

Authors' Addresses

   Thomas Dreibholz
   Simula Metropolitan Centre for Digital Engineering
   Pilestredet 52
   0167 Oslo
   Norway
   Email: dreibh@simula.no

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   URI:   https://www.simula.no/people/dreibh

   Xing Zhou
   Hainan University, College of Information Science and Technology
   Renmin Avenue 58
   570228 Haikou
   Hainan,
   China
   Phone: +86-898-66279141
   Email: zhouxing@hainu.edu.cn

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