Network Working Group T. Dreibholz Internet-Draft SimulaMet Intended status: Standards Track 16 September 2026 Expires: 20 March 2027 Handle Resolution Option for ASAP draft-dreibholz-rserpool-asap-hropt-39 Abstract This document describes the Handle Resolution option for the ASAP protocol. 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 Handle Resolution Option September 2026 1.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 1.3. Conventions . . . . . . . . . . . . . . . . . . . . . . . 3 2. Handle Resolution Option . . . . . . . . . . . . . . . . . . 3 2.1. Definition . . . . . . . . . . . . . . . . . . . . . . . 3 3. Reference Implementation . . . . . . . . . . . . . . . . . . 3 4. Testbed Platform . . . . . . . . . . . . . . . . . . . . . . 4 5. Security Considerations . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 8. Normative References . . . . . . . . . . . . . . . . . . . . 4 9. Informative References . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction Reliable Server Pooling defines protocols for providing highly available services. The Aggregate Server Access Protocol (ASAP) provides session management and server selection for applications. Upon request for a server selection -- denoted as handle resolution -- an ENRP server returns a list of selected PE identities. The number of PE identities to be returned is not specified by RSerPool. Furthermore, the ASAP protocol does not contain a way to let the requesting instance specify it. As shown in [11], [12], [13], selecting too many entries does not make sense for the application, but on the other hand also results in significant processing and network overhead. Furthermore, it has been shown in [14] that the number of requested elements is usually 1, but there are application cases where more PE identities have to be returned. That is, there should be a way to specify the number of requested PE items upon a handle resolution. 1.1. Scope The Handle Resolution option defined in this draft simply defines an option to let the PU-side specify the desired number of PE identities from the ENRP server. 1.2. Terminology The terms are commonly identified in related work and can be found in the Aggregate Server Access Protocol and Endpoint Handlespace Redundancy Protocol Common Parameters document [6]. Dreibholz Expires 20 March 2027 [Page 2] Internet-Draft Handle Resolution Option September 2026 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. Handle Resolution Option 2.1. Definition The Handle Resolution option MAY be used once in an ASAP Handle Resolution message sent from a PU to an ENRP server. It is defined as follows. 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 = 0x803f | Length=8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Items | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Items: 32 bits (unsigned integer) Contains the number of PE identities to be selected by the ENRP server. Setting it to 0xffffffff denotes obtaining as many PE identities as possible. A setting of 0 denotes using the ENRP server's default value; this default MUST be used if there is no Handle Resolution option given. The ENRP server SHOULD try to fulfill the request for the given number of items. Note that the high-order bits of the type field are set to 10, which means "skip this parameter and continue processing" if this parameter type is not supported by the ENRP server. This allows for interoperability with old implementations. 3. Reference Implementation The RSerPool reference implementation RSPLIB can be found at [17]. It supports the functionalities defined by [3], [4], [5], [6] and [8] as well as the options [9], [10] and the option defined in this document. An introduction to this implementation is provided in [11]. Dreibholz Expires 20 March 2027 [Page 3] Internet-Draft Handle Resolution Option September 2026 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 [16] and [15]. Further information can be found on the project website [18]. 5. Security Considerations Security considerations for RSerPool systems are described in [7]. 6. IANA Considerations This document does not require additional IANA actions beyond those already identified in the ENRP and ASAP protocol specifications. 7. Acknowledgments The author would like to thank Nihad Cosic, Dirk Hoffstadt, Michael Kohnen, Jobin Pulinthanath and Xing Zhou for their support. 8. 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, . [2] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [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, . [4] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate Server Access Protocol (ASAP)", RFC 5352, DOI 10.17487/RFC5352, September 2008, . [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, . Dreibholz Expires 20 March 2027 [Page 4] Internet-Draft Handle Resolution Option September 2026 [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, . [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, . [8] Dreibholz, T. and M. Tuexen, "Reliable Server Pooling Policies", RFC 5356, DOI 10.17487/RFC5356, September 2008, . [9] 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, . [10] 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, . 9. Informative References [11] Dreibholz, T., "Reliable Server Pooling – Evaluation, Optimization and Extension of a Novel IETF Architecture", 7 March 2007, . [12] Dreibholz, T. and E. P. Rathgeb, "Overview and Evaluation of the Server Redundancy and Session Failover Mechanisms in the Reliable Server Pooling Framework", International Journal on Advances in Internet Technology (IJAIT) Number 1, Volume 2, Pages 1–14, ISSN 1942-2652, 8 June 2009, . [13] Dreibholz, T. and E. P. Rathgeb, "An Evaluation of the Pool Maintenance Overhead in Reliable Server Pooling Systems", SERSC International Journal on Hybrid Dreibholz Expires 20 March 2027 [Page 5] Internet-Draft Handle Resolution Option September 2026 Information Technology (IJHIT) Number 2, Volume 1, Pages 17–32, ISSN 1738-9968, April 2008, . [14] Dreibholz, T. and E. P. Rathgeb, "On the Performance of Reliable Server Pooling Systems", Proceedings of the IEEE Conference on Local Computer Networks (LCN) 30th Anniversary Pages 200–208, ISBN 0-7695-2421-4, DOI 10.1109/LCN.2005.98, 16 November 2005, . [15] 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, . [16] 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, . [17] Dreibholz, T., "Thomas Dreibholz's RSerPool Page", 16 September 2026, . [18] 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 6]