Network Working Group T. Dreibholz Internet-Draft SimulaMet Intended status: Informational 16 September 2026 Expires: 20 March 2027 Ideas for a Next Generation of the Reliable Server Pooling Framework draft-dreibholz-rserpool-nextgen-ideas-26 Abstract This document collects ideas for a next generation of the Reliable Server Pooling framework. 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 20 March 2027. Copyright Notice Copyright (c) 2026 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 Dreibholz Expires 20 March 2027 [Page 1] Internet-Draft RSerPool Next Generation Ideas September 2026 1.1. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Reliable Server Pooling . . . . . . . . . . . . . . . . . 2 1.3. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. What to Change in the Next Generation of RSerPool? . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. Reference Implementation . . . . . . . . . . . . . . . . . . 4 6. Testbed Platform . . . . . . . . . . . . . . . . . . . . . . 4 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 8. Normative References . . . . . . . . . . . . . . . . . . . . 4 9. Informative References . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 1. Introduction 1.1. Abbreviations * ASAP: Aggregate Server Access Protocol * ENRP: Endpoint Handlespace Redundancy Protocol * ID: Identifier * MPTCP: Multi-Path Transmission Control Protocol * PE: Pool Element * PR: Pool Registrar * PU: Pool User * RSerPool: Reliable Server Pooling * SCTP: Stream Control Transmission Protocol * TCP: Transmission Control Protocol * VNFPOOL: Virtual Network Function Resource Pooling 1.2. Reliable Server Pooling Reliable Server Pooling (RSerPool) is defined in [1], [2], [3], [4], [5], [16], [6], [7]. There is also a detailed introduction provided in [17] as well as further informational material at [24]. RSerPool is therefore not introduced in more detail here. Dreibholz Expires 20 March 2027 [Page 2] Internet-Draft RSerPool Next Generation Ideas September 2026 1.3. Scope The scope of this document is to collect ideas on what to update/ change for a next generation of the RSerPool framework. It is a result of lessons learned over roughly two decades of RSerPool deployment (see also [18], [19], [20]) as well as ongoing discussions on applying RSerPool for Virtual Network Function Resource Pooling (VNFPOOL; as introduced in more detail in [15]). 2. What to Change in the Next Generation of RSerPool? * ENRP servers denote the management systems in the context of RSerPool. The term "server" is misleading, since ENRP servers are actually ENRP peers. Literature on RSerPool -- for example [17] -- therefore uses the more accurate term "Pool Registrar" (PR). A future revision of RSerPool should also use this term. (The RSerPool documents did not use "registrar" to avoid confusion with SIP registrars.) * Pool Element Identifiers (PE IDs) and Pool Registrar Identifiers (PR IDs) are 32-bit random numbers used for the identification of PEs and PRs. Since 64-bit CPUs have been standard for a long time, these IDs should be extended to 64 bits. * ENRP uses the Internet-16 checksum defined in [8] to detect handlespace inconsistencies. It is trivially possible to extend the underlying algorithm to 32 bits, and the computation is more efficient on today's CPUs. The checksum algorithm should therefore be changed. (The Internet-16 checksum was finally chosen in 2005 after long decisions to avoid any possible patent issues. The trivial extension of Internet-16 to Internet-32 is likely no longer an issue.) * PR failures lead to a possible concentration of all PUs and PEs at a single PR. To achieve better load balancing, the solution ENRP Takeover Suggestion -- as defined in [14] -- should be included in ENRP. * Upon handle resolution, a PR has to decide on how many PEs to select. Selecting too many entries causes additional overhead (which might be unnecessary), selecting too few may cause problems for applications. The extension Handle Resolution Option -- defined in [12] -- allows the PU to specify the number of PEs to be selected. This possibility should be integrated into ASAP. * RSerPool defines SCTP (defined in [9]) as the transport protocol for RSerPool. TCP, Multi-Path TCP (MPTCP; see [10]), and QUIC (see [11]) should be supported as additional transport protocols Dreibholz Expires 20 March 2027 [Page 3] Internet-Draft RSerPool Next Generation Ideas September 2026 for all RSerPool traffic. SCTP should still be the recommended choice, but allowing TCP/MPTCP could make deployment much easier. (SCTP is superior, but it lacks support in operating systems and underlying network infrastructure, such as firewalls and middleboxes.) 3. Security Considerations Security considerations for RSerPool can be found in [16]. 4. IANA Considerations This document introduces no additional considerations for IANA. 5. Reference Implementation The RSerPool reference implementation RSPLIB, including example applications, can be found at [24]. It supports the functionalities defined in [2], [3], [4], [5], and [16] as well as the options [12], [14], and [13]. An introduction to this implementation is provided in [17]. 6. 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 [21] and [20]. Further information can be found on the project website [25]. 7. Acknowledgments The author would like to thank Randall R. Stewart, Michael Tüxen, and Ning Zong for their discussions and support. 8. Normative References [1] Tuexen, M., Xie, Q., Stewart, R., Shore, M., Ong, L., Loughney, J., and M. Stillman, "Requirements for Reliable Server Pooling", RFC 3237, DOI 10.17487/RFC3237, January 2002, . [2] Lei, P., Ong, L., Tuexen, M., and T. Dreibholz, "An Overview of Reliable Server Pooling Protocols", RFC 5351, DOI 10.17487/RFC5351, September 2008, . Dreibholz Expires 20 March 2027 [Page 4] Internet-Draft RSerPool Next Generation Ideas September 2026 [3] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate Server Access Protocol (ASAP)", RFC 5352, DOI 10.17487/RFC5352, September 2008, . [4] Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A. Silverton, "Endpoint Handlespace Redundancy Protocol (ENRP)", RFC 5353, DOI 10.17487/RFC5353, September 2008, . [5] 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, . [6] Dreibholz, T. and M. Tuexen, "Reliable Server Pooling Policies", RFC 5356, DOI 10.17487/RFC5356, September 2008, . [7] Dreibholz, T. and J. Mulik, "Reliable Server Pooling MIB Module Definition", RFC 5525, DOI 10.17487/RFC5525, April 2009, . [8] Braden, R., Borman, D., and C. Partridge, "Computing the Internet checksum", RFC 1071, DOI 10.17487/RFC1071, September 1988, . [9] Stewart, R., Tüxen, M., and K. Nielsen, "Stream Control Transmission Protocol", RFC 9260, DOI 10.17487/RFC9260, June 2022, . [10] Ford, A., Raiciu, C., Handley, M., and O. Bonaventure, "TCP Extensions for Multipath Operation with Multiple Addresses", RFC 6824, DOI 10.17487/RFC6824, January 2013, . [11] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based Multiplexed and Secure Transport", RFC 9000, DOI 10.17487/RFC9000, May 2021, . [12] Dreibholz, T., "Handle Resolution Option for ASAP", Work in Progress, Internet-Draft, draft-dreibholz-rserpool- asap-hropt-38, 15 March 2026, . Dreibholz Expires 20 March 2027 [Page 5] Internet-Draft RSerPool Next Generation Ideas September 2026 [13] 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-37, 15 March 2026, . [14] Dreibholz, T. and X. Zhou, "Takeover Suggestion Flag for the ENRP Handle Update Message", Work in Progress, Internet-Draft, draft-dreibholz-rserpool-enrp-takeover-35, 15 March 2026, . [15] Zong, N., Dunbar, L., Shore, M., Lopez, D. R., and G. Karagiannis, "Virtualized Network Function (VNF) Pool Problem Statement", Work in Progress, Internet-Draft, draft-zong-vnfpool-problem-statement-06, 1 July 2014, . 9. Informative References [16] 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, . [17] Dreibholz, T., "Reliable Server Pooling – Evaluation, Optimization and Extension of a Novel IETF Architecture", 7 March 2007, . [18] Dreibholz, T. and E. P. Rathgeb, "A Powerful Tool-Chain for Setup, Distributed Processing, Analysis and Debugging of OMNeT++ Simulations", Proceedings of the 1st ACM/ICST International Workshop on OMNeT++ ISBN 978-963-9799-20-2, DOI 10.4108/ICST.SIMUTOOLS2008.2990, 7 March 2008, . [19] Dreibholz, T., "Evaluation and Optimisation of Multi-Path Transport using the Stream Control Transmission Protocol", Habilitation Treatise, 13 March 2012, . Dreibholz Expires 20 March 2027 [Page 6] Internet-Draft RSerPool Next Generation Ideas September 2026 [20] Dreibholz, T. and E. G. Gran, "Design and Implementation of the NorNet Core Research Testbed for Multi-Homed Systems", Proceedings of the 3rd 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, . [21] Gran, E. G., Dreibholz, T., and A. Kvalbein, "NorNet Core – A Multi-Homed Research Testbed", Computer Networks, Special Issue on Future Internet Testbeds Volume 61, Pages 75–87, ISSN 1389-1286, DOI 10.1016/j.bjp.2013.12.035, 14 March 2014, . [22] Dreibholz, T., "The NorNet Core Testbed – Introduction and Status", Proceedings of the 1st International NorNet Users Workshop (NNUW-1), 18 September 2013, . [23] Dreibholz, T., "The NorNet Core Testbed – An Experiment Tutorial", Proceedings of the 1st International NorNet Users Workshop (NNUW-1), 19 September 2013, . [24] Dreibholz, T., "Thomas Dreibholz's RSerPool Page", 16 September 2026, . [25] Dreibholz, T., "NorNet – A Real-World, Large-Scale Multi- Homing Testbed", 16 September 2026, . Author's Address Thomas Dreibholz Simula Metropolitan Centre for Digital Engineering Stensberggata 27 0170 Oslo Norway Email: dreibh@simula.no URI: https://www.simula.no/people/dreibh Dreibholz Expires 20 March 2027 [Page 7]