IP flow information exchange                                    L. Coene
Working group                                                    Siemens
Internet-Draft                                                 P. Conrad
Expires: August 14, 2003                               Temple University
                                                       February 13, 2003


        Reliable Server pool use in IP flow information exchange
               <draft-coene-rserpool-applic-ipfix-00.txt>

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

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   This Internet-Draft will expire on August 14, 2003.

Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This document describes the applicability of the relialeble server
   pool architecture to the IP flow information exchange using Endpoint
   Name Resolution Protocol(ENRP) function of Rserpool only. Data
   exchange in IPFIX between the router and the datacollector can be
   using a limited retransmission protocol.









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1. INTRODUCTION

   Reliable server pooling provides protocols for providing higly
   available services. The services are located in 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 transfered
   to the other server taking over. The mechanism for transfering this
   state information is NOT part of the Reliable server pooling
   architecture and/or protocols and must be provided by other
   protocols.

   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 pool protocols have to be used in order to
   provide a higly 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 Name Resolution
   Protocol Common Parameters document[RFCCOMM].















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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
   endpoint resolution protocol(ENRP) 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 info from different observation points).

   The observation point will query the ENRP server for resolution of a
   particular collector pool name and ENRP will return to the
   observation point of list of 1 or more collector points.

   The observation point will use its own transport protocols(TCP, UDP,
   SCTP, PR-SCTP) for exchanging the IPFIX data between the observation
   point and the collection point. If a collection 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 avialebility. The observation point will only
   query the ENRP server for server pool namer resolution.


























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3. Transport protocols suitable for IPFIX

   The exchange of IP flow information data between a observation point
   and a collection point consists of massive ammounts 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 collections
   points. Some data must arrive at the collectore while othr data migth
   arrive(if it get lost, no problem). The choice of relialeble or
   partial relialeble delivery has to be made by the observation point.
   This calls for a protocol that should have variable relialebility for
   the transport of its data, prefereably to be chosen by IPFIX
   protocols on a per-message base.

   PR-SCTP is the only know protocol which allows the choice of full,
   partial or no relialeble delivery of the message to its peer node.
   TCP will only allow full relialeble delivery, while UDP has only
   unrelialeble delivery and NO congestion control to speak of.































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4. Security considerations

   The protocols used in the Reliable server pool architecture only
   tries to increase the availability of the servers in the network.
   Rserpool protocols does 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 its user
   protocols.

   Rserpool architecture allows the use of different Transport protocols
   for its application and control data exchange. Those 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[RFC3057] for guidance on this issue.


































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5. Acknowledgments

   The authors wish to thank X, Y and M. Stillman and many others for
   their invaluable comments.















































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References

   [1]  Tuexen, M., Stewart, R., Shore, M., Xie, Q., Ong, L., Loughney,
        J. and M. Stillman, "Requirements for Reliable Server Pooling",
        RFC 3237, January 2002.

   [2]  Tuexen, M., Stewart, R., Shore, M., Xie, Q., Ong, L., Loughney,
        J. and M. Stillman, "Architecture for Reliable Server Pooling",
        Draft in progress , October 2002.

   [3]  Stewart, R., Xie, Q., Stillman, M. and M. Tuexen, "Aggregate
        Server Access Protocol (ASAP)", Draft in progress , October
        2002.

   [4]  Xie, Q., Stewart, R. and M. Stillman, "Endpoint Name Resolution
        Protocol (ENRP)", Draft in progress , October 2002.

   [5]  Stewart, R., Xie, Q., Stillman, M. and M. Tuexen, "Aggregate
        Server Access Protocol and Endpoint Name Resolution Protocol
        Common Parameters", Draft in progress , October 2002.

   [6]  Conrad, P. and P. Lei, ""Services Provided By Reliable Server
        Pooling", Draft in progress , January 2003.

   [7]  Stewart, R., Xie, Q., Morneault, K., Sharp, C., Schwarzbauer,
        H., Taylor, T., Rytina, I., Kalla, M., Zhang, L. and V. Paxson,
        ""Stream Control Transmission Protocol"", RFC 2960, October
        2000.

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


Authors' Addresses

   Lode Coene
   Siemens
   Atealaan 32
   Herentals  2200
   Belgium

   Phone: +32-14-252081
   EMail: lode.coene@siemens.com








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   Phil Conrad
   Temple University
   zzz
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   USA

   Phone: zzzz
   EMail: zzzz











































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Acknowledgement

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