Network Working Group                                       T. Dreibholz
Internet-Draft                              University of Duisburg-Essen
Intended status: Informational                                  L. Coene
Expires: January 6, 2010                          Nokia Siemens Networks
                                                               P. Conrad
                                                  University of Delaware
                                                            July 5, 2009


 Reliable Server Pooling Applicability for IP Flow Information Exchange
                draft-coene-rserpool-applic-ipfix-08.txt

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Abstract

   This document describes the applicability of the Reliable Server
   Pooling architecture to the IP Flow Information Exchange using the
   Aggregate Server Access Protocol (ASAP) functionality of RSerPool
   only.  Data exchange in IPFIX between the router and the data
   collector can be provided by a limited retransmission protocol.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  IPFIX using RSerPool  . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Architecture  . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Transport protocols suitable for IPFIX  . . . . . . . . . . . . 4
   4.  Security considerations . . . . . . . . . . . . . . . . . . . . 4
   5.  Reference Implementation  . . . . . . . . . . . . . . . . . . . 5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . . . 5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 5
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     9.2.  Informative References  . . . . . . . . . . . . . . . . . . 6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 7

























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1.  Introduction

   Reliable Server Pooling provides protocols for providing highly
   available services.  The services are located in a pool of redundant
   servers and if a server fails, another server will take over.  The
   only requirement put on these servers belonging to the pool is that
   if state is maintained by the server, this state must be transferred
   to the other server taking over.

   The goal is to provide server-based redundancy.  Transport and
   network level redundancy are handle by the transport and network
   layer protcols.

   The application may choose to distribute its traffic over the servers
   of the pool conforming to a certain policy.

   The application wishing to make use of RSerPool protocols may use
   different transport layers (such as UDP, TCP and SCTP).  However,
   some transport layers may have restrictions build in in the way they
   might be operating in the RSerPool architecture and its protocols.

1.1.  Scope

   The scope of this document is to explain the way that a minimal
   version of Reliable Server Pooling protocols have to be used in order
   to provide a highly available service towards IP Flow Information
   Exchange (IPFIX) protocols.

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 [RFC5354]


2.  IPFIX using RSerPool

2.1.  Architecture

   IP flow information is exchanged between observation points and
   collector points.  The observation points may try to find out via the
   Aggregate Server Access Protocol (ASAP, see [RFC5352]) which
   collector point(s) are active.  Both the observation and the
   collector point may have limitations for exchanging the information
   (observation point may have limited buffer space and collectors
   points may be overburdened with receiving lots of flow information
   from different observation points).




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   The observation point will query the ENRP server for resolution of a
   particular collector pool name and the ENRP server will return a list
   of one or more collector points to the observation point.

   The observation point will use its own transport protocols (TCP, UDP,
   SCTP, SCTP with PR-SCTP extension) for exchanging the IPFIX data
   between the observation point and the collector point.  If a
   collector point would fail, then the observation point will send its
   data towards a different collector point, belonging to the same
   collector pool.

   Collector points will announce themselves to the ENRP server and will
   be monitored for their availability.  The observation point will only
   query the ENRP server for server pool name resolution.


3.  Transport protocols suitable for IPFIX

   The exchange of IP flow information data between an observation point
   and a collection point consists of massive amounts of data.

   One collection point can service many observation points, therefore
   transport protocols must do congestion control (example: modifying
   the receive buffer space, thus reducing the incoming flow of data),
   so that the collection point is not overburdened by its observation
   points.  Some data must arrive at the collector while other data
   might arrive (if it gets lost: no problem).  The choice of reliable
   or partial reliable delivery has to be made by the observation point
   These requirements demand a protocol which provides variable
   transport reliability of its data: it should be able to chose the
   reliability by the IPFIX protocols on a a per-message base.

   SCTP [RFC4960] with PR-SCTP extension [RFC3758] is the only know
   protocol which allows the choice of full, partial or unreliable
   delivery of the message to its peer node.  TCP will only allow fully
   reliable delivery, while UDP only provides unreliable delivery and NO
   congestion control.


4.  Security considerations

   The protocols used in the Reliable Server Pooling architecture only
   try to increase the availability of the servers in the network.
   RSerPool protocols do not contain any protocol mechanisms which are
   directly related to user message authentication, integrity and
   confidentiality functions.  For such features, it depends on the
   IPSEC protocols or on Transport Layer Security (TLS) protocols for
   its own security and on the architecture and/or security features of



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   its user protocols.

   The RSerPool architecture allows the use of different transport
   protocols for its application and control data exchange.  These
   transport protocols may have mechanisms for reducing the risk of
   blind denial-of-service attacks and/or masquerade attacks.  If such
   measures are required by the applications, then it is advised to
   check the SCTP applicability statement RFC2057 [RFC3257] for guidance
   on this issue.


5.  Reference Implementation

   The RSerPool reference implementation RSPLIB can be found at
   [RSerPoolPage].  It supports the functionalities defined by
   [RFC5351], [RFC5352], [RFC5353], [RFC5354] and [RFC5356] as well as
   the options [I-D.dreibholz-rserpool-asap-hropt],
   [I-D.dreibholz-rserpool-enrp-takeover] and
   [I-D.dreibholz-rserpool-delay].  An introduction to this
   implementation is provided in [Dre2006].


6.  Security Considerations

   Security considerations for RSerPool systems are described by
   [RFC5355].


7.  IANA Considerations

   This document introduces no additional considerations for IANA.


8.  Acknowledgments

   The authors wish to thank Maureen Stillman and many others for their
   invaluable comments.


9.  References

9.1.  Normative References

   [RFC5351]  Lei, P., Ong, L., Tuexen, M., and T. Dreibholz, "An
              Overview of Reliable Server Pooling Protocols", RFC 5351,
              September 2008.

   [RFC5352]  Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,



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              "Aggregate Server Access Protocol (ASAP)", RFC 5352,
              September 2008.

   [RFC5353]  Xie, Q., Stewart, R., Stillman, M., Tuexen, M., and A.
              Silverton, "Endpoint Handlespace Redundancy Protocol
              (ENRP)", RFC 5353, September 2008.

   [RFC5354]  Stewart, R., Xie, Q., Stillman, M., and M. Tuexen,
              "Aggregate Server Access Protocol (ASAP) and Endpoint
              Handlespace Redundancy Protocol (ENRP) Parameters",
              RFC 5354, September 2008.

   [RFC5355]  Stillman, M., 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, September 2008.

   [RFC5356]  Dreibholz, T. and M. Tuexen, "Reliable Server Pooling
              Policies", RFC 5356, September 2008.

   [RFC3257]  Coene, L., "Stream Control Transmission Protocol
              Applicability Statement", RFC 3257, April 2002.

   [RFC3758]  Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P.
              Conrad, "Stream Control Transmission Protocol (SCTP)
              Partial Reliability Extension", RFC 3758, May 2004.

   [RFC4960]  Stewart, R., "Stream Control Transmission Protocol",
              RFC 4960, September 2007.

9.2.  Informative References

   [RSerPoolPage]
              Dreibholz, T., "Thomas Dreibholz's RSerPool Page",
              URL: http://tdrwww.iem.uni-due.de.de/dreibholz/rserpool/.

   [Dre2006]  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.

   [I-D.dreibholz-rserpool-asap-hropt]
              Dreibholz, T., "Handle Resolution Option for ASAP",
              draft-dreibholz-rserpool-asap-hropt-04 (work in progress),
              January 2009.



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   [I-D.dreibholz-rserpool-enrp-takeover]
              Dreibholz, T. and X. Zhou, "Takeover Suggestion Flag for
              the ENRP Handle Update Message",
              draft-dreibholz-rserpool-enrp-takeover-01 (work in
              progress), January 2009.

   [I-D.dreibholz-rserpool-delay]
              Dreibholz, T. and X. Zhou, "Definition of a Delay
              Measurement Infrastructure and Delay-Sensitive  Least-Used
              Policy for Reliable Server Pooling",
              draft-dreibholz-rserpool-delay-03 (work in progress),
              January 2009.


Authors' Addresses

   Thomas Dreibholz
   University of Duisburg-Essen, Institute for Experimental Mathematics
   Ellernstrasse 29
   45326 Essen, Nordrhein-Westfalen
   Germany

   Phone: +49-201-1837637
   Fax:   +49-201-1837673
   Email: dreibh@iem.uni-due.de
   URI:   http://www.iem.uni-due.de/~dreibh/


   Lode Coene
   Nokia Siemens Networks
   Atealaan 32
   Herentals  2200
   Belgium

   Phone: +32-14-252081
   Email: lode.coene@nsn.com


   Phillip Conrad
   University of Delaware
   103 Smith Hall
   Newark  DE 19716
   USA

   Phone: +1 302 831 8622
   Email: conrad@acm.org





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