INTERNET-DRAFT L. Coene(Ed) Internet Engineering Task Force Siemens Issued: June 2002 Expires: December 2002 Reliable Server pool applicability statement Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1ID-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract This document describes the applicability of the Aggregate Server Access Protocol(ASAP) and Endpoint Name Resolution Protocol(ENRP) developed for reliable server pooling. Also some guidance is given on the choice of underlying transport protocol(and corresponding transport protocol mapping) for transporting application data and ASAP/ENRP specific control data. Coene [Page 1] Draft Rserpool Applicability statement June 2002 Table of contents Reliable Server pooling Applicability statement ................ ii Chapter 1: Introduction ........................................ 2 Chapter 1.1: Scope ..... ....................................... 3 Chapter 1.2: Terminology ....................................... 3 Chapter 1.3: Contributors ...................................... 3 Chapter 2: Rserpool architecture ............................... 4 Chapter 2.1: Overview .......................................... 4 Chapter 2.2: ASAP/ENRP applicability ........................... 4 Chapter 2.3: Application and Control data Transport ............ 4 Chapter 2.4: Rserpool use between 2 pools ...................... 4 Chapter 3: Issues for Reliable Server pooling .................. 4 Chapter 3.1: State transfer between Pool Elements .............. 4 Chapter 4: Security considerations ............................. 5 Chapter 5: References and related work ......................... 5 Chapter 6: Acknowledgments ..................................... 6 Chapter 7: Author's address .................................... 6 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 Coene [Page 2] Draft Rserpool Applicability statement June 2002 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 Reliable server pool protocols have to be used in order to provide a higly available service towards the application in the network. 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]. 1.3 Contributors The following people contributed to the document: L. Coene(Editor), x, y and z. 2 Rserpool architecture 2.1 Overview A overview of the reliable server pool architecture is given in the Rserpool architecture document[RFCARCH]. 2.2 ASAP/ENRP applicability 2.3 Application and Control data Transport 2.4 Rserpool use between 2 pools 3 Issues for Reliable Server pooling 3.1 State transfer accoss the server pool Rserpool protocols(ENRP and ASAP) do NOT provide any service for transfering state information of a application from one Processing Element(PE) to another. 4 Security considerations Coene [Page 3] Draft Rserpool Applicability statement June 2002 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 Trasnport 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. 5 References and related work [RFC3237] Tuexen, M., Xie, Q., Stewart, R.R., Shore, M., Ong, L., Loughney, J., Stillman, M., "Requirements for Reliable Server Pooling", January 2002 [RFCARCH] Tuexen, M., Xie, Q., Stewart, R.R., Shore, M., Ong, L., Loughney, J., Stillman, M., "Architecture for Reliable Server Pooling", , October 2002. [RFCASAP] Stewart, R.R., Xie, Q., Stillman, M., "Aggregate Server Access Protocol (ASAP)", , work in progress [RFCENRP] Xie, Q., Stewart, R.R., Stillman, M., "Endpoint Name Resolution Protocol (ENRP)", , work in progress [RFCCOMM] Stewart, R.R., Xie, Q., "Aggregate Server Access Protocol and Endpoint Name Resolution Protocol Common Parameters", , work in progress [RFCSERV] Conrad, P., Lei, P., "Services Provided By Reliable Server Pooling", , work in progress [RFC2960] Stewart, R. R., Xie, Q., Morneault, K., Sharp, C. , , Coene [Page 4] Draft Rserpool Applicability statement June 2002 Schwarzbauer, H. J., Taylor, T., Rytina, I., Kalla, M., Zhang, L. and Paxson, V, "Stream Control Transmission Protocol", RFC2960, October 2000. [RF3257] Coene, L., Tuexen, M., Verwimp, G., Loughney, J., Stewart, R. R., Xie, Q., Holdrege, M., Belinchon, M.C., and Jungmayer, A., "Stream Control Transmission Protocol Applicability statement", RFC3257, April 2002. 6 Acknowledgments The authors wish to thank X, Y and M. Stillman and many others for their invaluable comments. 7 Author's Address Lode Coene Phone: +32-14-252081 Siemens Atea EMail: lode.coene@siemens.atea.be Atealaan 34 B-2200 Herentals Belgium Expires: December 2002 Full Copyright Statement Copyright (C) The Internet Society (2002). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. Coene [Page 5] Draft Rserpool Applicability statement June 2002 The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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