Internet DRAFT - draft-dreibholz-rserpool-enrp-takeover
draft-dreibholz-rserpool-enrp-takeover
Network Working Group T. Dreibholz
Internet-Draft SimulaMet
Intended status: Standards Track X. Zhou
Expires: 29 March 2024 Hainan University
26 September 2023
Takeover Suggestion Flag for the ENRP Handle Update Message
draft-dreibholz-rserpool-enrp-takeover-30
Abstract
This document describes the Takeover Suggestion Flag for the
ENRP_HANDLE_UPDATE message of the ENRP protocol.
Status of This Memo
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This Internet-Draft will expire on 29 March 2024.
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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.nntb.no/~dreibh/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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