IRTF P2PRG J. Buford Internet Draft Panasonic Expires: July 13, 2006 K. Ross Polytechnic M. Kolberg Stirling January 13, 2006 CORE Subgroup Problem Statement draft-irtf-p2prg-core-problem-statement-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. This document may only be posted in an Internet-Draft. 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 This Internet-Draft will expire on July 13,2006. Copyright Notice Copyright (C) The Internet Society (2006). All Rights Reserved. Buford Expires July 13, 2006 [Page 1] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 Abstract New research in the design of peer-to-peer overlay networks offers the possibility of addressing limitations of existing service, resource and content discovery methods. We identify the research goals to be pursued in investigating new designs for global scale service discovery. The purpose of this document is to attract participation from other researchers interested in these problems and to lead to a coordinated research approach within the P2PRG CORE subgroup. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC-2119 [RFC2119]. Table of Contents 1. Content, Resource and Service Discovery........................2 2. Definitions....................................................3 3. Problem Statement..............................................4 3.1. Global-Scale Service Discovery............................4 3.2. Service-Oriented Overlays.................................5 3.3. Internet Infrastructure...................................5 3.4. Content and Resource Discovery / Search...................5 4. Security Considerations........................................6 5. References.....................................................7 5.1. Normative References......................................7 5.2. Informative References....................................8 Author's Addresses...............................................10 Intellectual Property Statement..................................10 Disclaimer of Validity...........................................11 Copyright Statement..............................................11 Acknowledgment...................................................11 1. Content, Resource and Service Discovery Discovery of content, resources and services are fundamental operations for peers in a peer-to-peer network. Many discovery mechanisms have been proposed. However existing designs have limitations in one or more areas of scalability, security, interoperability, or generality. The purpose of this subgroup to evaluate existing research, identify requirements, and develop solutions for peer-to-peer content, resource, and service discovery in wide-area networks. While content, resource, and service discovery Buford Expires July 13, 2006 [Page 2] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 have been conventionally addressed by separate mechanisms, we are interested in identifying unified mechanisms where possible. As a minimum we are interested in global-scale service discovery. Existing methods for service discovery include client-server mechansisms (such as SLP [RFC2608][RFC2609]), mechanisms integrated into device network adapters (such as Bluetooth SDP [BLU2001][BLU2004] and Salutation [SAL1996]), mechanisms integrated in middleware platforms (such as Web services [W3C2004A] [W3C2004B] [W3C2004C], Jini [JINI2003A][JINI2003B], and JXTA [TRA2004]), and home network oriented solutions (UPnP SSDP [UPNP2000]). In addition there are experimental systems for service discovery such as SSDS [CZE1999] and these extensions to SLP: WASRV [ROS1997], wide- area SLP [HUA2000], and mesh-enhanced SLP [RFC3528][ZHA2000]; and the use of wide-area multicast to advertise and discover services [MIC2004]. Further there are various peer-to-peer overlay networks and proposed designs, both unstructured and structured by which large numbers of peers share content and services. Typically large-scale unstructured peer-to-peer systems use limited scope flooding or random walk to reach other peers with requests, whereas structured peer-to-peer systems use a distributed hash table (DHT) to store key-value peers. The integration of peer-to-peer overlay networks with service definition and lookup has emerged as "service overlay" [GU2004]. An example of mapping service definitions to a structured multi-hop overlay is INS/Twine [BAL2002]. An example of using peer-to-peer overlay for web services lookup is [SCH2004]. A related proposal is [BRA2004]. Associated with various discovery mechanisms are related mechanisms for service/resource advertisement, description, and invocation. More extensive surveys of existing methods of service discovery protocols include [BET2000][LEE2002][ZHU2002] and [TRA2004]. 2. Definitions Group: a collection of peers or groups of peers satisfying some membership constraint Search: a discovery mechanism in which content or resources stored in a peer-to-peer network can be searched using various methods including text search, keyword search, content-based retrieval or meta-data search Service: a computational function packaged for use by other nodes in a networked environment Buford Expires July 13, 2006 [Page 3] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 Service description: Information about a networked service such as type of service, name of service, attributes of service, location of service, invocation of service. May be stored in a document or at a service repository or at the node offering the service; may be broadcast or multicast by the node offering the service. May be machine readable or human readable or both. Service advertisement: the publication of a service description, in whole or part, by or on behalf of the service offerer, for access by other nodes Service composition: the definition of a new service using two or more existing services Service discovery: retrieval or access of a service description by nodes other than the service offerer, including browsing, search by name, class, type and or service attributes Service invocation: remote execution of a service over a computer network Service notification: an event signaling change in the availability or state of a service Service overlay: the use of an overlay network to store and lookup service descriptions 3. Problem Statement 3.1. Global-Scale Service Discovery A global-scale service discovery mechanism should provide the following capabilities: o Internet-wide service advertisement and discovery of services, such that any service on the Internet can be discovered by any peer on the Internet. The expected volume of transactions expected in a global service discovery mechanism is in the range of DNS lookup volume. o Ability to index service descriptions by geographic location and domain in which the services are available o Ability to index service descriptions by arbitrary meta data regarding the service o Support for creating and using composite services from services offered by different peers Buford Expires July 13, 2006 [Page 4] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 o Use of multiple service description formats which might be tailored by application or level of semantic description o Access to services, service descriptions, and service advertisements dependent on authorization rights o Access to services, service descriptions, and service advertisements by peer group membership o Individual domains can administer the service availability, security, and service descriptions In addition it is desirable that: o The mechanism can be used in isolation by peers in PANs, ad hoc networks, or other limited networking environments o Collections of peers can join and separate from other collections of peers without interruption a service discovery capability within the respective collections o The mechanism is compatible with existing service discovery mechanisms, possibly through gateways 3.2. Service-Oriented Overlays o The mechanism is open with respect to the overlay network, and should work with multiple distinct overlay networks o Different overlays supporting service discovery will vary by architecture, security, and performance characteristics 3.3. Internet Infrastructure o The mechanism may be used for portions Internet infrastructure services such as DNS [COX2002]. o The mechanism does not require changing existing Internet infrastructure 3.4. Content and Resource Discovery / Search o The mechanism for service discovery may be useful for content and resource discovery, and a unified design is desirable o Indexing, mapping, and lookup for specific discovery types in the overlay may vary Buford Expires July 13, 2006 [Page 5] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 4. Security Considerations There are no new security considerations in this document. Buford Expires July 13, 2006 [Page 6] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 5. References 5.1. Normative References [BLU2004] Bluetooth Specification version 2. Vol. 3 Core System Package. Part B Service Discovery Protocol (SDP). [BLU2001] Bluetooth Specification version 1.1. Service Discovery Application Profile. Part K:2. Feb 22, 2001. [IANASLP] IANA service location templates. http://www.iana.org/assignments/svrloc-templates/ [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2234] Crocker, D. and Overell, P.(Editors), "Augmented BNF for Syntax Specifications: ABNF", RFC 2234, Internet Mail Consortium and Demon Internet Ltd., November 1997. [RFC2608] E. Guttman, C. Perkins, J. Veizades, M. Day. Service Location Protocol, Version 2. IETF RFC 2608. June 1999. [RFC2609] E. Guttman, C. Perkins, J. Kempf. Service Templates and Service: Schemes. IETF RFC 2609. June 1999. [RFC3528] W. Zhao, H. Schulzrinne. Mesh-enhanced Service Location Protocol (mSLP). IETF RFC 3528. April 2003. [UPN2000] UPnP Forum. UPnP Device Architecture. Version 1. June 8, 2000. [W3C2004a]W3C. Web Services Architecture. http://www.w3.org/TR/2004/NOTE-ws-arch-20040211/. Feb 11, 2004. [W3C2004b]W3C. Web Services Description Language version 2.0 Part 1: Core Language. http://www.w3.org/TR/wsdl20 Aug 3, 2004. [W3C2004c]W3C. Web Services Description Language (WSDL) Version 2.0. Part 3: Bindings. http://www.w3.org/TR/wsdl20-bindings Aug 3, 2004. Buford Expires July 13, 2006 [Page 7] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 5.2. Informative References [BAL2002] M. Balazinska, H. Balakrishnan, and D. Karger. INS/Twine: A Scalable Peer-to-Peer Architecture for Intentional Resource Discovery. In Proceedings of Pervasive 2002. [BAR1999] M. Barbeau. Service discovery in a mobile agent API using SLP, Global Telecommunications Conference (GLOBECOM '99), 1999, 391-395 vol. 1a [BET2000] C. Bettstetter, C. Renner. A Comparison of Service Discovery Protocols and Implementation of the Service Location Protocol, In proceeding of Open European Summer School (EUNICE), Twente Netherlands, September 13-15, 2000. [BRA2004] William B. Bradley, David P. Maher. The NEMO P2P Service Orchestration Framework. Proceedings of the 37th Hawaii International Conference on System Sciences - 2004 [COL2003] Mesh-Enhanced SLP Project at Columbia Univ: http://www1.cs.columbia.edu/~zwb/project/slp/ [COX2002] R. Cox, A. Muthitacharoen, and R. T. Morris, Serving DNS using a Peer-to-Peer Lookup Service, IPTPS, Mar. 2002 [CZE1999] Czerwinski, S. E., et al. 1999. An architecture for a secure service discovery service. In Proceedings of the 5th Annual ACM/IEEE international Conference on Mobile Computing and Networking (Seattle, Washington, United States, August 15 - 19, 1999). MobiCom '99. ACM Press, New York, NY, 24-35 [FRE2004] Freudenthal, E. and Karamcheti, V. 2004. DisCo: Middleware for Securely Deploying Decomposable Services in Partly Trusted Environments. In Proceedings of the 24th international Conference on Distributed Computing Systems (Icdcs'04) (March 24 - 26, 2004). ICDCS. IEEE Computer Society, Washington, DC, 494-503. [GOT2002] K. Gottschalk, S. Graham, H. Kreger, J. Snell. Introduction to Web Service Architecture. IBM Systems J. v 41 n 2. 2002. [GU2004] Gu, X., Nahrstedt, K., and Yu, B. 2004. SpiderNet: An Integrated Peer-to-Peer Service Composition Framework. In Proceedings of the 13th IEEE international Symposium on High Performance Distributed Computing (Hpdc'04) - Volume 00 (June 04 - 06, 2004). HPDC. IEEE Computer Society, Washington, DC, 110-119. Buford Expires July 13, 2006 [Page 8] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 [HUA2000] An-Cheng Huang and Peter Steenkiste. A Flexible Architecture for Wide-Area Service Discovery,. The Third IEEE Conference on Open Architectures and Network Programming (OPENARCH 2000), March 26-27, 2000. [JIN2003a] Sun Microsystems. Jini Architecture Specification v 2. June 2003. [JIN2003b] Sun Microsystems. Jini™ Technology Core Platform Specification. June 2003. [LEE2002] C. Lee and S. Helal. Protocols for Service Discovery in Dynamic and Mobile Networks. Intl. J. of Computer Research. v. 11 n 1 pp. 1-12. 2002. [MIC2004] Microsoft. Web Services Dynamic Discovery (WS-Discovery). Oct 2004. [RAM2002] Raman, B., et al. 2002. The SAHARA Model for Service Composition across Multiple Providers. In Proceedings of the First international Conference on Pervasive Computing (August 26 - 28, 2002). F. Mattern and M. Naghshineh, Eds. Lecture Notes In Computer Science, vol. 2414. Springer- Verlag, London, 1-14. [ROS1997] J.Rosenberg, H.Schulzrinne, B.Suter. Wide Area Network Service Location. IETF draft-ietf-svrloc-wasrv-01.txt. Work in progress. Nov 14, 1997. [SAL1996] Salutation Consortium. Salutation Architecture Specification (part 1) Version 2.0c. www.salutation.org [SCH2004] C. Schmidt and M. Parashar, A Peer-to-Peer Approach to Web Service Discovery, World Wide Web Journal, Vol. 7, Issue 2, June 2004 [STE1998] M. v. Steen, F. J. Hauck, P. Homburg, and A. S. Tanenbaum, Locating Objects in Wide-Area Systems, IEEE Communications Magazine, January, 1998, pp. 104-109 [TRA2004] Bernard Traversat, Ahkil Arora, Mohamed Abdelaziz, Mike Duigou, Carl Haywood, Jean-Christophe Hugly, Eric Pouyoul, Bill Yeager. Project JXTA 2.0 Super-Peer Virtual Network. www.jxta.org Buford Expires July 13, 2006 [Page 9] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 [ZHA2000] Weibin Zhao, Henning Schulzrinne, and Erik Guttman, "mSLP - Mesh-enhanced Service Location Protocol", in International Conference on Computer Communication and Network, Las Vegas, Nevada, October 2000. [ZHU2002] F. Zhu, M. Mutka, L. Ni. Classification of Service Discovery in Pervasive Computing Environments. MSU-CSE-02- 24, Michigan State University, EastLansing, 2002. Author's Addresses John Buford Panasonic Digital Networking Lab 2 Research Way, 3rd Floor Princeton, NJ 08540 Email: buford@research.panasonic.com Keith Ross Department of Computer and Information Science Polytechnic University Six MetroTech Center Brooklyn, NY 11201 Email: ross@poly.edu Mario Kolberg Room 4B60, Cottrell Building Department of Computing Science and Mathematics University of Stirling Stirling FK9 4LA Scotland Email: mkolberg@ieee.org Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this Buford Expires July 13, 2006 [Page 10] Internet-Draft P2PRG CORE Subgroup Problem Statement January 2006 specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Buford Expires July 13, 2006 [Page 11]