draft-ietf-rserpool-policies-06.txt   draft-ietf-rserpool-policies-07.txt 
Network Working Group M. Tuexen Network Working Group M. Tuexen
Internet-Draft Muenster Univ. of Applied Sciences Internet-Draft Muenster Univ. of Applied Sciences
Intended status: Experimental T. Dreibholz Intended status: Experimental T. Dreibholz
Expires: March 25, 2008 University of Duisburg-Essen Expires: May 12, 2008 University of Duisburg-Essen
September 22, 2007 November 9, 2007
Reliable Server Pooling Policies Reliable Server Pooling Policies
draft-ietf-rserpool-policies-06.txt draft-ietf-rserpool-policies-07.txt
Status of this Memo Status of this Memo
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This Internet-Draft will expire on March 25, 2008. This Internet-Draft will expire on May 12, 2008.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This document describes server pool policies for Reliable Server This document describes server pool policies for Reliable Server
Pooling including considerations for implementing them at ENRP Pooling including considerations for implementing them at ENRP
servers and pool users. servers and pool users.
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5.3.2. ENRP Server Considerations . . . . . . . . . . . . . . 11 5.3.2. ENRP Server Considerations . . . . . . . . . . . . . . 11
5.3.3. Pool User Considerations . . . . . . . . . . . . . . . 11 5.3.3. Pool User Considerations . . . . . . . . . . . . . . . 11
5.3.4. Pool Member Selection Policy Parameter . . . . . . . . 11 5.3.4. Pool Member Selection Policy Parameter . . . . . . . . 11
5.4. Randomized Least Used Policy . . . . . . . . . . . . . . . 11 5.4. Randomized Least Used Policy . . . . . . . . . . . . . . . 11
5.4.1. Description . . . . . . . . . . . . . . . . . . . . . 11 5.4.1. Description . . . . . . . . . . . . . . . . . . . . . 11
5.4.2. ENRP Server Considerations . . . . . . . . . . . . . . 12 5.4.2. ENRP Server Considerations . . . . . . . . . . . . . . 12
5.4.3. Pool User Considerations . . . . . . . . . . . . . . . 12 5.4.3. Pool User Considerations . . . . . . . . . . . . . . . 12
5.4.4. Pool Member Selection Policy Parameter . . . . . . . . 12 5.4.4. Pool Member Selection Policy Parameter . . . . . . . . 12
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. A New Table for RSerPool Policy Types . . . . . . . . . . 12 7.1. A New Table for RSerPool Policy Types . . . . . . . . . . 13
8. Reference Implementation . . . . . . . . . . . . . . . . . . . 14 8. Reference Implementation . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
9.1. Normative References . . . . . . . . . . . . . . . . . . . 14 9.1. Normative References . . . . . . . . . . . . . . . . . . . 14
9.2. Informative References . . . . . . . . . . . . . . . . . . 14 9.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
Intellectual Property and Copyright Statements . . . . . . . . . . 16 Intellectual Property and Copyright Statements . . . . . . . . . . 16
1. Introduction 1. Introduction
The protocols defined in ENRP [5], ASAP [4] and Parameters [3] The protocols defined in ENRP [5], ASAP [4] and Parameters [3]
support a variety of server policies. Some of the policies use support a variety of server policies. Some of the policies use
dynamic load information of the pool elements and others do not. dynamic load information of the pool elements and others do not.
Therefore, we classify them as adaptive and non-adaptive. The Therefore, we classify them as adaptive and non-adaptive. The
selection of the pool user is performed by two different entities. selection of the pool user is performed by two different entities.
Some of the consequences for policies which are not stateless are Some of the consequences for policies which are not stateless are
described in Performance [8]. described in Performance [10].
Therefore this document describes not only packet formats but also Therefore this document describes not only packet formats but also
gives a detailed description of the procedures to be followed at the gives a detailed description of the procedures to be followed at the
ENRP servers and the pool users to implement each server policy. ENRP servers and the pool users to implement each server policy.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC2119 [1]. document are to be interpreted as described in RFC2119 [1].
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The Least Used with Degradation (LUD) policy extends the LU policy by The Least Used with Degradation (LUD) policy extends the LU policy by
a load degradation value describing the pool element's load increment a load degradation value describing the pool element's load increment
when a new service association is accepted. when a new service association is accepted.
5.2.2. ENRP Server Considerations 5.2.2. ENRP Server Considerations
For every pool element entry, a degradation counter MUST be stored. For every pool element entry, a degradation counter MUST be stored.
When a pool element entry is added or updated by registration or When a pool element entry is added or updated by registration or
reregistration, this counter MUST be set to 0. When an entry is reregistration, this counter MUST be set to 0. When an entry is
selected for being returned to a pool user, the internal degradation selected for being returned to a pool user, the internal degradation
counter MUST be incremented by the entry's load degradation constant. counter MUST be incremented by 1. The selection of pool element
The selection of pool element entries is handled like for LU, except entries is handled like for LU, except that the selected pool element
that the selected pool element entries SHOULD have the lowest entries SHOULD have the lowest possible sum of load value +
possible sum of load value + degradation counter. degradation counter * load degradation value.
5.2.3. Pool User Considerations 5.2.3. Pool User Considerations
See LU policy. See LU policy.
5.2.4. Pool Member Selection Policy Parameter 5.2.4. Pool Member Selection Policy Parameter
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Load: Current load of the pool element. o Load: Current load of the pool element.
o Load Degradation: Load Degradation constant of the pool element. o Load Degradation: Load Degradation constant of the pool element.
5.4. Randomized Least Used Policy 5.4. Randomized Least Used Policy
5.4.1. Description 5.4.1. Description
The Randomized Least Used (RLU) policy combines LU and WRAND. That The Randomized Least Used (RLU) policy combines LU and WRAND. That
is, the pool element entries are selected randomly; the probability is, the pool element entries are selected randomly. The probability
for a pool element entry to be selected is the ratio of 100%-load to for a pool element entry A, utilized with load_A, to be selected is
the sum of all pool elements' load values. (0xFFFFFFFF - load_A) / (sum(0xFFFFFFFF-load_x)), i.e. this PE's
unload part related to the whole pool unload rate.
5.4.2. ENRP Server Considerations 5.4.2. ENRP Server Considerations
The ENRP server SHOULD behave like WRAND, having every PE's weight The ENRP server SHOULD behave like WRAND, having every PE's weight
set to (0xffffffff - Load value provided by the pool element). set to (0xffffffff - Load value provided by the pool element).
5.4.3. Pool User Considerations 5.4.3. Pool User Considerations
See WRAND policy. See WRAND policy.
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0x40000000 (reserved by IETF) RFCXXXX 0x40000000 (reserved by IETF) RFCXXXX
0x40000001 Least Used RFCXXXX 0x40000001 Least Used RFCXXXX
0x40000002 Least Used with Degradation RFCXXXX 0x40000002 Least Used with Degradation RFCXXXX
0x40000003 Priority Least Used RFCXXXX 0x40000003 Priority Least Used RFCXXXX
0x40000004 Randomized Least Used RFCXXXX 0x40000004 Randomized Least Used RFCXXXX
0x40000005 (reserved by IETF) RFCXXXX 0x40000005 (reserved by IETF) RFCXXXX
... ...
0x7fffffff (reserved by IETF) RFCXXXX 0x7fffffff (reserved by IETF) RFCXXXX
0x80000000 (user-defined, non-standard policy) RFCXXXX 0x80000000 (private use, non-standard policy) RFCXXXX
... ...
0xffffffff (user-defined, non-standard policy) RFCXXXX 0xffffffff (private use, non-standard policy) RFCXXXX
For registering at IANA an RSerPool Policy Type in this table a For registering at IANA an RSerPool Policy Type in this table a
request has to be made to assign such a number. This number must be request has to be made to assign such a number. This number must be
unique and use the appropiate upper bits. The "Specification unique and use the appropiate upper bits. The "Specification
Required" policy of RFC2434 [2] MUST be applied. Required" policy of RFC2434 [2] MUST be applied.
The Policy Type space from 0x80000000 to 0xffffffff is designated for
private use.
8. Reference Implementation 8. Reference Implementation
The reference implementation of RSerPool and the policies described The reference implementation of RSerPool and the policies described
in this document is available at [7]. in this document is available at [7].
9. References 9. References
9.1. Normative References 9.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement [1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997. Levels", BCP 14, RFC 2119, March 1997.
[2] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA [2] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October 1998. Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998.
[3] Stewart, R., "Aggregate Server Access Protocol (ASAP) and [3] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate
Endpoint Handlespace Redundancy Protocol (ENRP) Parameters", Server Access Protocol (ASAP) and Endpoint Handlespace
draft-ietf-rserpool-common-param-12 (work in progress), Redundancy Protocol (ENRP) Parameters",
July 2007. draft-ietf-rserpool-common-param-13 (work in progress),
September 2007.
[4] Stewart, R., "Aggregate Server Access Protocol (ASAP)", [4] Stewart, R., Xie, Q., Stillman, M., and M. Tuexen, "Aggregate
draft-ietf-rserpool-asap-16 (work in progress), July 2007. Server Access Protocol (ASAP)", draft-ietf-rserpool-asap-17
(work in progress), September 2007.
[5] Stewart, R., "Endpoint Handlespace Redundancy Protocol (ENRP)", [5] Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A.
draft-ietf-rserpool-enrp-16 (work in progress), July 2007. Silverton, "Endpoint Handlespace Redundancy Protocol (ENRP)",
draft-ietf-rserpool-enrp-17 (work in progress), September 2007.
[6] Gopal, R., Guttman, E., Holdrege, M., Sengodan, S., and M. [6] Stillman, M., Gopal, R., Guttman, E., Holdrege, M., and S.
Stillman, "Threats Introduced by Rserpool and Requirements for Sengodan, "Threats Introduced by RSerPool and Requirements for
Security in response to Threats", Security in Response to Threats",
draft-ietf-rserpool-threats-08 (work in progress), draft-ietf-rserpool-threats-09 (work in progress),
September 2007. October 2007.
9.2. Informative References 9.2. Informative References
[7] Dreibholz, T., "Thomas Dreibholz's RSerPool Page", [7] Dreibholz, T., "Thomas Dreibholz's RSerPool Page",
URL: http://tdrwww.exp-math.uni-essen.de/dreibholz/rserpool/. URL: http://tdrwww.exp-math.uni-essen.de/dreibholz/rserpool/.
[8] Dreibholz, T., Rathgeb, E., and M. Tuexen, "Load Distribution [8] Dreibholz, T., "Reliable Server Pooling -- Evaluation,
Optimization and Extension of a Novel IETF Architecture", Ph.D.
Thesis University of Duisburg-Essen, Faculty of Economics,
Institute for Computer Science and Business Information
Systems, URL: http://duepublico.uni-duisburg-essen.de/servlets/
DerivateServlet/Derivate-16326/Dre2006-final.pdf, March 2007.
[9] Dreibholz, T. and E. Rathgeb, "On the Performance of Reliable
Server Pooling Systems", Proceedings of the 30th IEEE Local
Computer Networks Conference, November 2005.
[10] Dreibholz, T., Rathgeb, E., and M. Tuexen, "Load Distribution
Performance of the Reliable Server Pooling Framework", Performance of the Reliable Server Pooling Framework",
Proceedings of the 4th IEEE International Conference on Proceedings of the 4th IEEE International Conference on
Networking, April 2005. Networking, April 2005.
Authors' Addresses Authors' Addresses
Michael Tuexen Michael Tuexen
Muenster University of Applied Sciences Muenster University of Applied Sciences
Stegerwaldstrasse 39 Stegerwaldstrasse 39
48565 Steinfurt 48565 Steinfurt
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