Network Working GroupAbbie.A. Barbir Internet-Draft Nortel Networks Expires:January 31,June 11, 2003 R. Chen AT&T Labs M. Hofmann Bell Labs/Lucent Technologies H. Orman Purple Streak Development R. Penno Nortel NetworksG. Tomlinson The Tomlinson Group August 2,December 11, 2002 An Architecture for Open Pluggable Edge Services (OPES)draft-ietf-opes-architecture-03draft-ietf-opes-architecture-04 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 asInternet- Drafts.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 onJanuary 31,June 11, 2003. Copyright Notice Copyright (C) The Internet Society (2002). All Rights Reserved. Abstract This memo defines an architecturefor a cooperativethat enables the creation of an application service in which a data provider, a data consumer, and zero or more application entities cooperativelyrealizeimplement a data stream service. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. The Architecture . . . . . . . . . . . . . . . . . . . . . . 4 2.1 OPES Entities . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.1 Data Dispatcher . . . . . . . . . . . . . . . . . . . . . .45 2.2 OPES Flows . . . . . . . . . . . . . . . . . . . . . . . . .56 2.3 OPES Rules . . . . . . . . . . . . . . . . . . . . . . . . .67 2.4 Callout Servers . . . . . . . . . . . . . . . . . . . . . . 7 2.5 Tracing Facility . . . . . . . . . . . . . . . . . . . . . .89 3. Security and Privacy Considerations . . . . . . . . . . . .1011 3.1 Trust Domains . . . . . . . . . . . . . . . . . . . . . . .1011 3.2 Establishing Trust and Service Authorization . . . . . . . . 12 3.3 Callout protocol . . . . . . . . . . . . . . . . . . . . . .11 3.313 3.4 Privacy . . . . . . . . . . . . . . . . . . . . . . . . . .11 3.4 Establishing trust14 3.5 End-to-end Integrity . . . . . . . . . . . . . . . . . . . . 14 4. IAB Architectural and Policy Considerations for OPES . . . .11 3.5 End-to-end Integrity15 4.1 IAB consideration (2.1) One-party consent . . . . . . . . . 15 4.2 IAB consideration (2.2) IP-layer communications . . . . . . 15 4.3 IAB consideration (3.1 and 3.2) Notification . . . . .12 4.. . . 15 4.4 IAB consideration (3.3) Non-blocking . . . . . . . . . . . . 15 4.5 IAB consideration (4.1) URI resolution . . . . . . . . . . . 15 4.6 IAB consideration (4.2) Reference validity . . . . . . . . . 16 4.7 IAB consideration (4.3) Application addressing extensions . 16 4.8 IAB consideration (5.1) Privacy . . . . . . . . . . . . . . 16 5. Security Considerations . . . . . . . . . . . . . . . . . . 17 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . 18 7. Summary . . . . . . . . . . . . . . . . . . . . . . . . . .1319 Normative References . . . . . . . . . . . . . . . . . . . . 20 Informative References . . . . .14 Authors' Addresses. . . . . . . . . . . . . . 21 Authors' Addresses . . . . . . . .14 A. Acknowledgements. . . . . . . . . . . . . 21 A. Acknowledgements . . . . . . . . . .16 Full Copyright Statement. . . . . . . . . . . . 23 Intellectual Property and Copyright Statements . . . . . .17. 24 1. Introduction When supplying a data stream service between a provider and a consumer, the need may arise to provision the use of other application entities, in addition to the provider and consumer. For example, some party may wish to customize a data stream as a service to a consumer. The customization step might be based on the customer's resource availability (e.g., display capabilities). In some casesinit may be beneficial to provide a customization service at a network location between the provider and consumer host rather than at one of these endpoints. For certain services performed onend-userbehalf of the end-user, this may be the only option of service deployment. In this case,onezero or more additional application entities may participate in the data stream service. There are many possible provisioning scenarios which make a data stream service attractive.InThe OPES Use Cases and Deployment Scenarios [1]a descriptiondocument provides examples ofseveral scenariosOPES services. The document discusses services that modify requests, services that modify responses and services that create responses. It isprovided.recommended that the document on OPES Use Cases and Deployment Scenarios [1] be read before reading this document. This document presents the architectural components of Open Pluggable Edge Services (OPES) that are needed in order to perform a data stream service. The architecture addresses the IAB considerations described in [2]. These considerations are covered inthevarious parts of thedocument, specifically with respect to tracing (Section 2.5) anddocument. Section 2.5 addresses tracing, section 3 addresses security considerations. In section 4 a summary of IAB considerations(Section 3).and how the architecture addresses them is provided. The document is organized as follows: Section 2 introduces the OPES architecture. Section 3 discusses OPES security and privacy considerations. Section 4 addresses IAB considerations for OPES. Section 5 discusses security considerations. Section 6 addresses IANA considerations. Section 7 provides a summary of the architecture and the requirements for interoperability. 2. The Architecture The architecture of Open Pluggable Edge Services (OPES) can be described in terms of three interrelated concepts, mainly: o OPES entities: processes operating in the network; o OPES flows: data flows that are cooperatively realized by the OPES entities; and, o OPES rules: these specify when and how to execute OPESintermediaryservices. 2.1 OPES Entities An OPES entity is an application that operates on a data flow between a data provider application and a data consumer application. OPES entities can be: o an OPES service application, which analyzes and possibly transforms messages exchanged between the data provider application and the data consumer application; o a data dispatcher, which invokes an OPES service application based on an OPES ruleset and application-specific knowledge.In the network, OPES entities reside inside OPES processors.The cooperative behavior of OPES entities introduces additional functionality for each data flow provided that it matches the OPES rules. In the network, OPES entities reside inside OPES processors. In the current work, an OPES processor MUST include a data dispatcher. Furthermore, the data provider and data consumer applications are not considered as OPES entities. In order to provide verifiable system integrity (see section 3.1 on trust domains below), facilitate deployment of end-to-end encryption and data integrity control , OPES processors MUST be: o explicitly addressable at the IP layer by the end user (data consumer application). This requirement does not preclude a chain of OPES processors with the first one in the chain explicitly addressed at the IP layer by the end user (data consumer application). o consented to by either the data consumer or data provider application. The details of this process is beyond the scope of the current work. The OPES architecture is largely independent of the protocol that is used by theOPES entitiesdata provider application and the data consumer application to exchange data. However, this document selects HTTP[4][3] as the example for the underlying protocol in OPES flows. 2.1.1 Data Dispatcher Data dispatchers include a ruleset that can be compiled from several sources andmustMUST resolve into an unambiguous result. The combined ruleset enables an OPES processor to determine which service applications to invoke for which data flow. Accordingly, the data dispatcher constitutes an enhanced policy enforcement point, where policy rules are evaluated, service-specific data handlers and state information is maintained, as depicted in Figure 1.---------------------------------------------------------------------+----------+ | callout | | server | +----------+ || || || || +--------------------------+ |+----------++-----------+ || | | | OPES | || | | | service | || | || appl ||application| || | |+----------++-----------+ || | | +----------------------+ | OPES flow <---->| | data dispatcher and | |<----> OPES flow | | policy enforcement | | | +----------------------+ | | OPES | | processor | +--------------------------+ Figure 1: Data Dispatchers---------------------------------------------------------------------The architecture allows for more than one policy enforcement point to be present on an OPES flow. 2.2 OPES Flows An OPES flow is a cooperative undertaking between a data provider application, a data consumer application, zero or more OPES service applications, andzeroone or more data dispatchers.In order to understandSince policies are enforced by data dispatchers, thetrust relationships between OPES entities, eachpresence of at least one data dispatcher islabeled as residingrequired inan administrative domain. Entities associated with a giventhe OPESflow may reside in one or more administrative domains. For example, Figure 2 depicts a data flow (also known as an "OPES flow"), that spans two administrative domains. --------------------------------------------------------------------- consumer administrative domain provider administrative domain +------------------------------+ +------------------------------+ | | | | |flow. data OPES| |OPES data| | consumerprovider processor| |A processorprovider | | | | | | +----------+ +--------+ | | +--------+ +----------+ | |N consumer +-----------+ +-----------+ . +-----------+ +-----------+ | data | | OPES || |. | OPES | | data | || |consumer ||service| service | . ||serviceservice | | provider || | | appl | | appl | | | | appl | | appl | | | +----------+ +--------+ | | +--------+ +----------+ | | | | | ||application| |application| . |application| |application| +-----------+ +-----------+ . +-----------+ +-----------+ | | | | . | | | | | HTTP | | HTTP || |. | HTTP | | HTTP | | | | | . | | | || | | | | | +----------+ +--------+ | | +--------+ +----------+ | |+-----------+ +-----------+ . +-----------+ +-----------+ | TCP/IP | | TCP/IP || |. | TCP/IP | | TCP/IP || | +----------+ +--------+ | | +--------+ +----------+ | |+-----------+ +-----------+ . +-----------+ +-----------+ || || ||| |. || || ||| | ============= ================= ============= | | | | | +------------------------------+ +------------------------------+================ =====.======== =========== | <----------------- OPES flow----------------->-------------------> | Figure 2: An OPES flow---------------------------------------------------------------------Figure 2 depicts two data dispatchers that are present in the OPES flow.However, theThe architecture allows forzeroone or more data dispatchers to be present in any flow. 2.3 OPES Rules OPES policy regarding services and the data provided to them is determined by a ruleset consisting of OPES rules. The rules consist of a set of conditions and related actions. The ruleset is the superset of all OPES rules on the processor. The OPES ruleset determines which service applications will operate on a data stream.The communication of data stream elements to an application is performed by data dispatchers.In this model, all datafiltersdispatchers are invoked for all flows. In order to ensure predictable behavior, the OPES architecture requires the use of a standardized schema for the purpose of defining and interpreting the ruleset. The OPES architecture does not require a mechanism for configuring a ruleset into a data dispatcher. This is treated as a local matter for each implementation (e.g., through the use of a text editor, secure upload protocol, and soon). Future revisions of the architecture may introduceon), as long as sucha requirement.mechanism complies with the requirements set forth in section 3. 2.4 Callout Servers The evaluation of the OPES ruleset determines which service applications will operate on a data stream. How the ruleset is evaluated is not the subject of the architecture, except to note that itmustMUST result in the same unambiguous result in all implementations. In some cases it may be useful for the OPES processor to distribute the responsibility of serviceevaluationexecution by communicating with one or more callout servers. A data dispatcher invokes the services of a callout server by using the OPES callout protocol (OCP). The requirements for the OCP are given in[7].[6]. The OCP is application- agnostic, being unaware of the semantics of the encapsulated application protocol (e.g., HTTP). However, theOCP mustdata dispatcher MUST incorporate a service aware vectoring capability that parses the data flow according to the ruleset and delivers the data tothe OPES service application that can be local or remote. In this model, OPES applications may be executedeitheron the same processor (or even in the same application environment) withthedispatcherlocal oron a differentremote OPESprocessor through OCP.service application. The general interaction situation is depicted in Figure 3, which illustrates the positions and interaction of different components of OPES architecture.---------------------------------------------------------------------+--------------------------+ |+----------++-----------+ | | | OPES | | | | service | | +---------------+ +-----------+ | |application| |appl|| |Callout ServerCallout | | Callout | |+----------++-----------+ | | Server A | | Server X | | || | | +--------+ | |X| | +----------------------+ | | | OPES | | | | | | data dispatcher | | | | Service| | | +--------+| | +----------------------+ | | |App2Appl A | | | | OPES || | || || | | +--------+ | | |Service || | +---------+ +-------+ | | || | | |AppXAppl X || |+---------+| HTTP | | | | | +--------+ | ... | +--------|| | |HTTP| | OCP |=========| | OCP | | | || | |+---------|+---------+ +-------+ | | +--------+ | | +------+ | |+---------+| | || | +---------------+ | | OCP | | | | TCP/IP | =======================================| | | | | | | | +------+ | || TCP/IP | | | | =====| | |============== OPES ====== | | |+---------+ |Data Flow+-----------++--------------------------++--------||-||-------------+ || || +--------+ || || +--------+ |data |== =========================================|data | |producer| |consumer| +--------+ +--------+ Figure 3: Interaction of OPES Entities---------------------------------------------------------------------2.5 Tracing Facility The OPES architecture requires that each data dispatcherto provideprovides tracing facilities that allow the appropriate verification of its operation. The OPES architecture requires that tracing be feasible on the OPES flow per OPES processor using in-band annotation. One of those annotations could be a URI with more detailed information on thetransformation that occurred to the data onOPES services being executed in the OPES flow. Providing the ability for in-band annotation MAY require header extensions on the application protocol that is used (e.g., HTTP). However, the presence of an OPES processor in the data request/ response flow SHALL NOT interfere with the operations of non-OPES aware clients and servers. The support of these extensions to the base protocol HTTP is not required by non-OPES clients and servers. OPES processorsmustMUST obey tracing, reporting and notification requirements set by the center of authority in the trust domain to which OPES processor belongs. As part of these requirements OPES processor may be instructed to reject or ignore such requirements that originate from other trust domains. 3. Security and Privacy Considerations Each data flowmustMUST be secured in accordance with several policies. The primary stakeholders are the data consumer and the data provider. The secondary stakeholders are the entities to which they may have delegated their trust. The other stakeholders are the owners of the callout servers. Any of these parties may be participants in the OPES flow. These partiesmustMUST have a model, explicit or implicit, describing their trust policy; which of the other parties are trusted to operate on data, and what security enhancements are required for communication. The trust might be delegated for all data, or it might be restricted to granularity as small as an application data unit. All parties that are involved in enforcing policiesmustMUST communicate the policies to the parties that are involved. These parties are trusted to adhere to the communicated policies. In order to delegate fine-grained trust, the partiesmustMUST convey policy information by implicit contract, by a setup protocol, by a dynamic negotiation protocol, or in-line with application data headers. 3.1 Trust Domains The delegation of authority starts at either a data consumer or data provider and moves to more distant entities in a "stepwise" fashion. Stepwise means A delegates to B and B delegates to C and so forth. The entities thus "colored" by the delegation are said to form a trust domain with respect to the original delegating party. Here, "Colored" means that if the first step in the chain is the data provider, then the stepwise delegation "colors" the chain with that data "provider" color. The only colors that are defined are the data "provider" and the data "consumer". Delegation of authority (coloring) propagates from the content producer start of authority or from the content consumer start of authority, that may be different from the end points in the data flow. Figure 4 illustrates administrative domains and out-of-band rules and policy distribution. provider administrative domain consumer administrative domain +------------------------------+ +-------------------------------+ | +--------------+ | | +--------------+ | | |Provider | <- out-of-band rules, -> |Consumer | | | |Administrative|~~>~~~: policies and ~<~|Administrative| | | |Authority | : service authorization : |Authority | | | +--------------+ : | | : +--------------+ | | : : | | : : | | : : | | : : | | +----------+ : | | : +----------+ | | | callout | +---------+ | | +---------+ | callout | | | | server |====| | | | | |====| server | | | +----------+ | | | | | | +----------+ | | | OPES | | | | OPES | | | +----------+ |processor| | | |processor| +----------+ | | | | | | | | | | | | | | | data | | | | | | | | data | | | | provider | | | | | | | | consumer | | | | | +---------+ | | +---------+ +----------+ | | +----------+ || || | | || || +----------+ | | || || || | | || || || | | ============= ================= =========== | | | | | +-------------------------------+ +-------------------------------+ | <----------------- OPES flow -----------------> | Figure 4: OPES administrative domains and policy distribution In order to understand the trust relationships between OPES entities, each is labeled as residing in an administrative domain. Entities associated with a given OPES flow may reside in one or more administrative domains. An OPES processor may be in several trust domains at any time. There is no restriction on whether the OPES processors are authorized by data consumers and/or data providers. The original party has the option of forbidding or limiting redelegation. An OPES processormustMUST have a representation of its trust domain memberships that it can report in whole or in part for tracing purposes. ItmustMUST include the name of the partywhichthat delegated each privilege to it. 3.2 Establishing Trust and Service Authorization The OPES processor will have configuration policy specifying what privileges the callout servers have and how they are to be identified. OPES uses standard protocols for authentication and otherwise security communication with callout servers. An OPES processor will have a trusted method for receiving configuration information such as rules for the data dispatcher, trusted callout servers, primary parties that opt-in or opt-out of individual services, etc. Protocol(s) for policy/rule distribution are out of scope for this document, but the OPES architecture assumes the existence of such a mechanism. Requirements for authorization mechanism are set in a separate document. Certain service requests, positive or negative, may be done in-band (for example OPES service bypass request, e.g. User agent can insert an HTTP header like "Bypass-OPES"). Such requests MUST be authenticated. The way OPES entities will honor such requests is subordinate to the authorization policies effective at that moment. 3.3 Callout protocol The determination of whether or not OPES processors will use the measures that are described in the previous section during their communication with callout servers depends on the details of how the primary parties delegated trust to the OPES processors and the trust relationship between the OPES processors and the callout server. If the OPES processors are in a single administrative domain with strong confidentiality guarantees, then encryption may be optional. However, it is recommended that for all cases that encryption and strong authentication be used. If the delegation mechanism names the trusted parties and their privileges in some way that permits authentication, then the OPES processors will be responsible for enforcing the policy and for using authentication as part of that enforcement. The callout serversmustMUST be aware of the policy governing the communication path. TheymustMUST not, for example, communicate confidential information to auxiliary servers outside the trust domain. A separate security associationmustMUST be used for each channel established between an OPES processor and a callout server. The channelsmustMUST be separate for different primary parties.3.33.4 Privacy Some data from data consumers is considered "private" or "sensitive", and OPES processorsmustMUST both advise the primary parties ofthetheir privacy policy and respect the policies of the primary parties. The privacy informationmustMUST be conveyed on a per-flow basis. This can be accomplished by using current available privacy techniques such as P3P [9] and HTTP privacy capabilities. The callout serversmustMUST also participate in the handling of private data, and theymustMUST be prepared to announce their own capabilities and to enforce the policy required by the primary parties.3.4 Establishing trust The OPES processor will have configuration policy specifying what privileges the callout servers have and how they are to be identified. This is especially critical for third-party (fourth- party, etc.) callout servers. OPES uses standard protocols for authenticating and otherwise security communication with callout servers. An OPES processor will have a trusted method for receiving configuration information such as rules for the data dispatcher, trusted callout servers, primary parties that opt-in or opt-out of individual services, etc.3.5 End-to-end Integrity Digital signature techniques can be used to mark data changes in such a way that a third-party can verify that the changes are or are not consistent with the originating party's policy. This requires an inline manner of specifying policy and its binding to data, a trace of changes and the party making the changes, and strong identities and authentication methods. Strong end-to-end integrity can fulfill some of the functions required by "tracing". 4. IAB Architectural and Policy Considerations for OPES This section addresses the IAB considerations for OPES [2] and summarizes how the architecture addresses them. 4.1 IAB consideration (2.1) One-party consent The IAB recommends that all OPES services are explicitly authorized by one of the application-layer end-hosts (that is, either the data consumer application or the data provider application). The current work requires that either the data consumer application or the data provider application consent to OPES services. These requirements have been addressed in sections 2 (section 2.1) and 3. 4.2 IAB consideration (2.2) IP-layer communications The IAB recommends that OPES processors must be explicitly addressed at the IP layer by the end user (data consumer application). This requirement has been addressed in section 2.1, whereby the architecture requires that OPES processors be addressable at the IP layer by the data consumer application. 4.3 IAB consideration (3.1 and 3.2) Notification The IAB recommends that the OPES architecture incorporates tracing facilities. Tracing enables data consumer and data provider applications to detect and respond to actions performed by OPES processors that are deemed inappropriate to the data consumer or data provider applications. Section 3.2 of this document discusses the tracing and notification facilities that must be supported by OPES services. 4.4 IAB consideration (3.3) Non-blocking The OPES architecture requires the specification of extensions to HTTP. These extension will provide the data consumer application to request a non-OPES version of the content from the data provider application. These requirements is covered in Section 3.2 4.5 IAB consideration (4.1) URI resolution This consideration recommends that OPES documentation must be clear in describing that OPES services as being applied to the result of URI resolution, not as URI resolution itself. This requirement has been addressed in sections 2.5 and 3.2, whereby the proposed architecture requires OPES entities to document all the transformations that have been performed. 4.6 IAB consideration (4.2) Reference validity This consideration recommends that all proposed services must define their impact on inter- and intra-document reference validity. This requirement has been addressed in section 2.5 and throughout the document whereby OPES entities is required to document the performed transformations. 4.7 IAB consideration (4.3) Application addressing extensions This consideration recommends that any OPES services that cannot be achieved while respecting the above two considerations may be reviewed as potential requirements for Internet application addressing architecture extensions, but must not be undertaken as ad hoc fixes. The current work does not require extensions of the Internet application addressing architecture. 4.8 IAB consideration (5.1) Privacy This consideration recommends that the overall OPES framework must provide for mechanisms for end users to determine the privacy policies of OPES intermediaries. This consideration has been addressed in section 3. 5. Security Considerations The proposed work has to deal with security from various prospective. There are security and privacy issues that relate to data consumer application, callout protocol and the OPES flow. In [7] threat analysis of OPES entities are discussed. 6. IANA Considerations The proposed work will evaluate current protocols for OCP. If the work determines that a new protocol need to be developed, then there may be a need to request new numbers from IANA. 7. Summary Although the architecture supports a wide range of cooperative transformation services, it has few requirements for interoperability. The necessary and sufficient elements are specified in the following documents: o the OPES ruleset schema[6][5] which defines the syntax and semantics of the rules interpreted by a data dispatcher; and, o the OPES callout protocol (OCP)[7][6] which defines the requirements for the protocol between a data dispatcher and a callout server. Normative References [1] McHenry, S., et. al, "OPES Scenarios and Use Cases",Internet- DraftInternet-Draft TBD, May 2002. [2] Floyd, S. and L. Daigle, "IAB Architectural and Policy Considerations for Open Pluggable Edge Services", RFC 3238, January 2002. [3]Westerinen, A., Schnizlein, J., Strassner, J., Scherling, M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry, J. and S. Waldbusser, "Terminology for Policy-Based Management", RFC 3198, November 2001. [4]Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L., Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.[5][4] OPES working group, "OPES Service Authorization and Enforcement Requirements", Internet-Draft TBD, May 2002.[6][5] OPES working group, "OPES Ruleset Schema", Internet-Draft TBD, May 2002.[7][6] A. Beck et al., "Requirements for OPES Callout Protocols", Internet-Drafthttp://www.ietf.org/internet-drafts/draft-ietf- opes-protocol-reqs-00.txt, Mayhttp://www.ietf.org/internet-drafts/ draft-ietf-opes-protocol-reqs-03.txt, December 2002. [7] A. Barbir et al., "Security Threats and Risks for Open Pluggable Edge Services", Internet-Draft http://www.ietf.org/ internet-drafts/draft-ietf-opes-threats-00.txt, October 2002. Informative References [8] Westerinen, A., Schnizlein, J., Strassner, J., Scherling, M., Quinn, B., Herzog, S., Huynh, A., Carlson, M., Perry, J. and S. Waldbusser, "Terminology for Policy-Based Management", RFC 3198, November 2001. [9] L. Cranor, et. al, "The Platform for Privacy Preferences 1.0 (P3P1.0) Specification", W3C Recommendation 16 http:// www.w3.org/TR/2002/REC-P3P-20020416/ , April 2002. Authors' Addresses Abbie Barbir Nortel Networks 3500 Carling Avenue Nepean, Ontario K2H 8E9 Canada Phone: +1 613 763 5229 EMail: abbieb@nortelnetworks.com Robin Chen AT&T Labs Room E219, 180 Park Avenue Florham Park, NJ 07932 US Phone: +1 973 360 8653 EMail: chen@research.att.com Markus Hofmann Bell Labs/Lucent Technologies Room 4F-513 101 Crawfords Corner Road Holmdel, NJ 07733 US Phone: +1 732 332 5983 EMail: hofmann@bell-labs.com Hilarie Orman Purple Streak Development EMail: ho@alum.mit.edu Reinaldo Penno Nortel Networks4555 Great America Parkway Santa Clara,2305 Mission College Boulevard San Jose, CA9505495134 US Phone: EMail: rpenno@nortelnetworks.comGary Tomlinson The Tomlinson Group EMail: gary@tomlinsongroup.netAppendix A. Acknowledgements This document is the product of OPES WG. Oskar Batuner (Independent consultant) and Andre Beck (Lucent) are additional authors that have contributed to this current document. Earlier versions of this work was done by Gary Tomlinson (The Tomlinson Group) and Michael Condry (Intel). The authors gratefully acknowledge the contributions of:Marshall T. Rose,John Morris,Oskar Batuner,MarkBaker andBaker, IanCooper.Cooper and Marshall T. Rose. Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property 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; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication 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 implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. 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. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors orassigns.assignees. 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. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society.