< draft-ietf-opes-architecture-03.txt		draft-ietf-opes-architecture-04.txt >
	Network Working Group Abbie. Barbir		Network Working Group A. Barbir
	Internet-Draft Nortel Networks		Internet-Draft Nortel Networks
	Expires: January 31, 2003 R. Chen		Expires: June 11, 2003 R. Chen
	AT&T Labs		AT&T Labs
	M. Hofmann		M. Hofmann
	Bell Labs/Lucent Technologies		Bell Labs/Lucent Technologies
	H. Orman		H. Orman
	Purple Streak Development		Purple Streak Development
	R. Penno		R. Penno
	Nortel Networks		Nortel Networks
	G. Tomlinson		December 11, 2002
	The Tomlinson Group
	August 2, 2002
	An Architecture for Open Pluggable Edge Services (OPES)		An Architecture for Open Pluggable Edge Services (OPES)
	draft-ietf-opes-architecture-03		draft-ietf-opes-architecture-04
	Status of this Memo		Status of this Memo
	This document is an Internet-Draft and is in full conformance with		This document is an Internet-Draft and is in full conformance with
	all provisions of Section 10 of RFC2026.		all provisions of Section 10 of RFC2026.
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	Copyright Notice		Copyright Notice
	Copyright (C) The Internet Society (2002). All Rights Reserved.		Copyright (C) The Internet Society (2002). All Rights Reserved.
	Abstract		Abstract
	This memo defines an architecture for a cooperative application		This memo defines an architecture that enables the creation of an
	service in which a data provider, a data consumer, and zero or more		application service in which a data provider, a data consumer, and
	application entities cooperatively realize a data stream service.		zero or more application entities cooperatively implement a data
			stream service.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. The Architecture . . . . . . . . . . . . . . . . . . . . . . 4		2. The Architecture . . . . . . . . . . . . . . . . . . . . . . 4
	2.1 OPES Entities . . . . . . . . . . . . . . . . . . . . . . . 4		2.1 OPES Entities . . . . . . . . . . . . . . . . . . . . . . . 4
	2.1.1 Data Dispatcher . . . . . . . . . . . . . . . . . . . . . . 4		2.1.1 Data Dispatcher . . . . . . . . . . . . . . . . . . . . . . 5
	2.2 OPES Flows . . . . . . . . . . . . . . . . . . . . . . . . . 5		2.2 OPES Flows . . . . . . . . . . . . . . . . . . . . . . . . . 6
	2.3 OPES Rules . . . . . . . . . . . . . . . . . . . . . . . . . 6		2.3 OPES Rules . . . . . . . . . . . . . . . . . . . . . . . . . 7
	2.4 Callout Servers . . . . . . . . . . . . . . . . . . . . . . 7		2.4 Callout Servers . . . . . . . . . . . . . . . . . . . . . . 7
	2.5 Tracing Facility . . . . . . . . . . . . . . . . . . . . . . 8		2.5 Tracing Facility . . . . . . . . . . . . . . . . . . . . . . 9
	3. Security and Privacy Considerations . . . . . . . . . . . . 10		3. Security and Privacy Considerations . . . . . . . . . . . . 11
	3.1 Trust Domains . . . . . . . . . . . . . . . . . . . . . . . 10		3.1 Trust Domains . . . . . . . . . . . . . . . . . . . . . . . 11
	3.2 Callout protocol . . . . . . . . . . . . . . . . . . . . . . 11		3.2 Establishing Trust and Service Authorization . . . . . . . . 12
	3.3 Privacy . . . . . . . . . . . . . . . . . . . . . . . . . . 11		3.3 Callout protocol . . . . . . . . . . . . . . . . . . . . . . 13
	3.4 Establishing trust . . . . . . . . . . . . . . . . . . . . . 11		3.4 Privacy . . . . . . . . . . . . . . . . . . . . . . . . . . 14
	3.5 End-to-end Integrity . . . . . . . . . . . . . . . . . . . . 12		3.5 End-to-end Integrity . . . . . . . . . . . . . . . . . . . . 14
	4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 13		4. IAB Architectural and Policy Considerations for OPES . . . . 15
	References . . . . . . . . . . . . . . . . . . . . . . . . . 14		4.1 IAB consideration (2.1) One-party consent . . . . . . . . . 15
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 14		4.2 IAB consideration (2.2) IP-layer communications . . . . . . 15
	A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16		4.3 IAB consideration (3.1 and 3.2) Notification . . . . . . . . 15
	Full Copyright Statement . . . . . . . . . . . . . . . . . . 17		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 . . . . . . . . . . . . . . . . . . . . . . . . . . 19
			Normative References . . . . . . . . . . . . . . . . . . . . 20
			Informative References . . . . . . . . . . . . . . . . . . . 21
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 21
			A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 23
			Intellectual Property and Copyright Statements . . . . . . . 24
	1. Introduction		1. Introduction
	When supplying a data stream service between a provider and a		When supplying a data stream service between a provider and a
	consumer, the need may arise to provision the use of other		consumer, the need may arise to provision the use of other
	application entities, in addition to the provider and consumer. For		application entities, in addition to the provider and consumer. For
	example, some party may wish to customize a data stream as a service		example, some party may wish to customize a data stream as a service
	to a consumer. The customization step might be based on the		to a consumer. The customization step might be based on the
	customer's resource availability (e.g., display capabilities).		customer's resource availability (e.g., display capabilities).
	In some cases in may be beneficial to provide a customization service		In some cases it may be beneficial to provide a customization service
	at a network location between the provider and consumer host rather		at a network location between the provider and consumer host rather
	than at one of these endpoints. For certain services performed on		than at one of these endpoints. For certain services performed on
	end-user behalf this may be the only option of service deployment.		behalf of the end-user, this may be the only option of service
	In this case, one or more additional application entities may		deployment. In this case, zero or more additional application
	participate in the data stream service. There are many possible		entities may participate in the data stream service. There are many
	provisioning scenarios which make a data stream service attractive.		possible provisioning scenarios which make a data stream service
	In [1] a description of several scenarios is provided.		attractive. The OPES Use Cases and Deployment Scenarios [1] document
			provides examples of OPES services. The document discusses services
			that modify requests, services that modify responses and services
			that create responses. It is 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		This document presents the architectural components of Open Pluggable
	Edge Services (OPES) that are needed in order to perform a data		Edge Services (OPES) that are needed in order to perform a data
	stream service. The architecture addresses the IAB considerations		stream service. The architecture addresses the IAB considerations
	described in [2]. These considerations are covered in the various		described in [2]. These considerations are covered in various parts
	parts of the document, specifically with respect to tracing (Section		of the document. Section 2.5 addresses tracing, section 3 addresses
	2.5) and security considerations (Section 3).		security considerations. In section 4 a summary of IAB
			considerations and how the architecture addresses them is provided.
	The document is organized as follows: Section 2 introduces the OPES		The document is organized as follows: Section 2 introduces the OPES
	architecture. Section 3 discusses security considerations. Section		architecture. Section 3 discusses OPES security and privacy
	4 provides a summary of the architecture and the requirements for		considerations. Section 4 addresses IAB considerations for OPES.
	interoperability.		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		2. The Architecture
	The architecture of Open Pluggable Edge Services (OPES) can be		The architecture of Open Pluggable Edge Services (OPES) can be
	described in terms of three interrelated concepts, mainly:		described in terms of three interrelated concepts, mainly:
	o OPES entities: processes operating in the network;		o OPES entities: processes operating in the network;
	o OPES flows: data flows that are cooperatively realized by the		o OPES flows: data flows that are cooperatively realized by the
	OPES entities; and,		OPES entities; and,
	o OPES rules: these specify when and how to execute OPES		o OPES rules: these specify when and how to execute OPES services.
	intermediary services.
	2.1 OPES Entities		2.1 OPES Entities
	An OPES entity is an application that operates on a data flow between		An OPES entity is an application that operates on a data flow between
	a data provider application and a data consumer application. OPES		a data provider application and a data consumer application. OPES
	entities can be:		entities can be:
	o an OPES service application, which analyzes and possibly		o an OPES service application, which analyzes and possibly
	transforms messages exchanged between the data provider		transforms messages exchanged between the data provider
	application and the data consumer application;		application and the data consumer application;
	o a data dispatcher, which invokes an OPES service application based		o a data dispatcher, which invokes an OPES service application based
	on OPES ruleset and application-specific knowledge.		on an OPES ruleset and application-specific knowledge.
	In the network, OPES entities reside inside OPES processors. The		The cooperative behavior of OPES entities introduces additional
	cooperative behavior of OPES entities introduces additional
	functionality for each data flow provided that it matches the OPES		functionality for each data flow provided that it matches the OPES
	rules.		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 the current work, the data provider and data consumer applications		In order to provide verifiable system integrity (see section 3.1 on
	are not considered as OPES entities. The OPES architecture is		trust domains below), facilitate deployment of end-to-end encryption
	largely independent of the protocol that is used by the OPES entities		and data integrity control , OPES processors MUST be:
	to exchange data. However, this document selects HTTP [4] as the
	example for the underlying protocol in OPES flows.		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 the data provider application and the data consumer
			application to exchange data. However, this document selects HTTP
			[3] as the example for the underlying protocol in OPES flows.
	2.1.1 Data Dispatcher		2.1.1 Data Dispatcher
	Data dispatchers include a ruleset that can be compiled from several		Data dispatchers include a ruleset that can be compiled from several
	sources and must resolve into an unambiguous result. The combined		sources and MUST resolve into an unambiguous result. The combined
	ruleset enables an OPES processor to determine which service		ruleset enables an OPES processor to determine which service
	applications to invoke for which data flow. Accordingly, the data		applications to invoke for which data flow. Accordingly, the data
	dispatcher constitutes an enhanced policy enforcement point, where		dispatcher constitutes an enhanced policy enforcement point, where
	policy rules are evaluated, service-specific data handlers and state		policy rules are evaluated, service-specific data handlers and state
	information is maintained, as depicted in Figure 1.		information is maintained, as depicted in Figure 1.
	---------------------------------------------------------------------
	+----------+		+----------+
	| callout |		| callout |
	| server |		| server |
	+----------+		+----------+
	||		||
	||		||
	||		||
	||		||
	+--------------------------+		+--------------------------+
	| +----------+ || |		| +-----------+ || |
	| | OPES | || |		| | OPES | || |
	| | service | || |		| | service | || |
	| | appl | || |		| |application| || |
	| +----------+ || |		| +-----------+ || |
	| +----------------------+ |		| +----------------------+ |
	OPES flow <---->| | data dispatcher and | |<----> OPES flow		OPES flow <---->| | data dispatcher and | |<----> OPES flow
	| | policy enforcement | |		| | policy enforcement | |
	| +----------------------+ |		| +----------------------+ |
	| OPES |		| OPES |
	| processor |		| processor |
	+--------------------------+		+--------------------------+
	Figure 1: Data Dispatchers		Figure 1: Data Dispatchers
	---------------------------------------------------------------------		The architecture allows for more than one policy enforcement point to
			be present on an OPES flow.
	The architecture allows more than one policy enforcement point to be
	present on an OPES flow.
	2.2 OPES Flows		2.2 OPES Flows
	An OPES flow is a cooperative undertaking between a data provider		An OPES flow is a cooperative undertaking between a data provider
	application, a data consumer application, zero or more OPES service		application, a data consumer application, zero or more OPES service
	applications, and zero or more data dispatchers.		applications, and one or more data dispatchers.
	In order to understand the trust relationships between OPES entities,		Since policies are enforced by data dispatchers, the presence of at
	each is labeled as residing in an administrative domain. Entities		least one data dispatcher is required in the OPES flow.
	associated with a given OPES flow may reside in one or more
	administrative domains.
	For example, Figure 2 depicts a data flow (also known as an "OPES		data OPES OPES data
	flow"), that spans two administrative domains.		provider processor A processor N consumer
	---------------------------------------------------------------------		+-----------+ +-----------+ . +-----------+ +-----------+
			| data | | OPES | . | OPES | | data |
			| consumer | | service | . | service | | provider |
			|application| |application| . |application| |application|
			+-----------+ +-----------+ . +-----------+ +-----------+
			| | | | . | | | |
			| HTTP | | HTTP | . | HTTP | | HTTP |
			| | | | . | | | |
			+-----------+ +-----------+ . +-----------+ +-----------+
			| TCP/IP | | TCP/IP | . | TCP/IP | | TCP/IP |
			+-----------+ +-----------+ . +-----------+ +-----------+
			|| || || . || || ||
			================ =====.======== ===========
	consumer administrative domain provider administrative domain		| <----------------- OPES flow -------------------> |
	+------------------------------+ +------------------------------+
	| | | |
	| data OPES | | OPES data |
	| consumer processor | | processor provider |
	| | | |
	| +----------+ +--------+ | | +--------+ +----------+ |
	| | data | | OPES | | | | OPES | | data | |
	| | consumer | |service | | | |service | | provider | |
	| | appl | | appl | | | | appl | | appl | |
	| +----------+ +--------+ | | +--------+ +----------+ |
	| | | | | | | | | | | |
	| | HTTP | | HTTP | | | | HTTP | | HTTP | |
	| | | | | | | | | | | |
	| +----------+ +--------+ | | +--------+ +----------+ |
	| | TCP/IP | | TCP/IP | | | | TCP/IP | | TCP/IP | |
	| +----------+ +--------+ | | +--------+ +----------+ |
	| || || || | | || || || |
	| ============= ================= ============= |
	| | | |
	+------------------------------+ +------------------------------+
	| <----------------- OPES flow -----------------> |
	Figure 2: An OPES flow		Figure 2: An OPES flow
	---------------------------------------------------------------------
	Figure 2 depicts two data dispatchers that are present in the OPES		Figure 2 depicts two data dispatchers that are present in the OPES
	flow. However, the architecture allows for zero or more data		flow. The architecture allows for one or more data dispatchers to be
	dispatchers to be present in any flow.		present in any flow.
	2.3 OPES Rules		2.3 OPES Rules
	OPES policy regarding services and the data provided to them is		OPES policy regarding services and the data provided to them is
	determined by a ruleset consisting of OPES rules. The rules consist		determined by a ruleset consisting of OPES rules. The rules consist
	of a set of conditions and related actions. The ruleset is the		of a set of conditions and related actions. The ruleset is the
	superset of all OPES rules on the processor. The OPES ruleset		superset of all OPES rules on the processor. The OPES ruleset
	determines which service applications will operate on a data stream.		determines which service applications will operate on a data stream.
	The communication of data stream elements to an application is		In this model, all data dispatchers are invoked for all flows.
	performed by data dispatchers. In this model, all data filters are
	invoked for all flows.
	In order to ensure predictable behavior, the OPES architecture		In order to ensure predictable behavior, the OPES architecture
	requires the use of a standardized schema for the purpose of defining		requires the use of a standardized schema for the purpose of defining
	and interpreting the ruleset. The OPES architecture does not require		and interpreting the ruleset. The OPES architecture does not require
	a mechanism for configuring a ruleset into a data dispatcher. This		a mechanism for configuring a ruleset into a data dispatcher. This
	is treated as a local matter for each implementation (e.g., through		is treated as a local matter for each implementation (e.g., through
	the use of a text editor, secure upload protocol, and so on). Future		the use of a text editor, secure upload protocol, and so on), as long
	revisions of the architecture may introduce such a requirement.		as such mechanism complies with the requirements set forth in section
			3.
	2.4 Callout Servers		2.4 Callout Servers
	The evaluation of OPES ruleset determines which service applications		The evaluation of the OPES ruleset determines which service
	will operate on a data stream. How the ruleset is evaluated is not		applications will operate on a data stream. How the ruleset is
	the subject of the architecture, except to note that it must result		evaluated is not the subject of the architecture, except to note that
	in the same unambiguous result in all implementations.		it MUST result in the same unambiguous result in all implementations.
	In some cases it may be useful for the OPES processor to distribute		In some cases it may be useful for the OPES processor to distribute
	the responsibility of service evaluation by communicating with one or		the responsibility of service execution by communicating with one or
	more callout servers. A data dispatcher invokes the services of a		more callout servers. A data dispatcher invokes the services of a
	callout server by using the OPES callout protocol (OCP). The		callout server by using the OPES callout protocol (OCP). The
	requirements for the OCP are given in [7]. The OCP is application-		requirements for the OCP are given in [6]. The OCP is application-
	agnostic, being unaware of the semantics of the encapsulated		agnostic, being unaware of the semantics of the encapsulated
	application protocol (e.g., HTTP). However, the OCP must		application protocol (e.g., HTTP). However, the data dispatcher MUST
	incorporate a service aware vectoring capability that parses the data		incorporate a service aware vectoring capability that parses the data
	flow according to the ruleset and delivers the data to the OPES		flow according to the ruleset and delivers the data to either the
	service application that can be local or remote.		local or remote OPES service application.
	In this model, OPES applications may be executed either on the same
	processor (or even in the same application environment) with the
	dispatcher or on a different OPES processor through OCP. The general
	interaction situation is depicted in Figure 3, which illustrates the
	positions and interaction of different components of OPES
	architecture.
	---------------------------------------------------------------------		The general interaction situation is depicted in Figure 3, which
			illustrates the positions and interaction of different components of
			OPES architecture.
	+--------------------------+		+--------------------------+
	| +----------+ |		| +-----------+ |
	| | OPES | |		| | OPES | |
	| | service | | +---------------+ +-----------+		| | service | | +---------------+ +-----------+
	| | appl | | |Callout Server | | Callout |		| |application| | | Callout | | Callout |
	| +----------+ | | A | | Server |		| +-----------+ | | Server A | | Server X |
	| || | | +--------+ | | X |		| || | | +--------+ | | |
	| +----------------------+ | | | OPES | | | |		| +----------------------+ | | | OPES | | | |
	| | data dispatcher | | | | Service| | | +--------+|		| | data dispatcher | | | | Service| | | +--------+|
	| +----------------------+ | | | App2 | | | | OPES ||		| +----------------------+ | | | Appl A | | | | OPES ||
	| || | | +--------+ | | |Service ||		| || || | | +--------+ | | |Service ||
	| +-------+ | | || | | | AppX ||		| +---------+ +-------+ | | || | | | Appl X ||
	| +---------+ | | | | +--------+ | ... | +--------||		| | HTTP | | | | | +--------+ | ... | +--------||
	| | HTTP | | OCP |=========| | OCP | | | || |		| | | | OCP |=========| | OCP | | | || |
	| +---------| +-------+ | | +--------+ | | +------+ |		| +---------+ +-------+ | | +--------+ | | +------+ |
	| +---------+ || | +---------------+ | | OCP | |		| | | || | +---------------+ | | OCP | |
	| | | =======================================| | |		| | TCP/IP | =======================================| | |
	| | | | | +------+ |		| | | | | +------+ |
	| | TCP/IP | | | |		| +---------+ | +-----------+
	=====| | |============== OPES ====== | |		+--------||-||-------------+
	| +---------+ | Data Flow +-----------+		|| ||
	+--------------------------+		+--------+ || || +--------+
			|data |== =========================================|data |
			|producer| |consumer|
			+--------+ +--------+
	Figure 3: Interaction of OPES Entities		Figure 3: Interaction of OPES Entities
	---------------------------------------------------------------------
	2.5 Tracing Facility		2.5 Tracing Facility
	The OPES architecture requires that each data dispatcher to provide		The OPES architecture requires that each data dispatcher provides
	tracing facilities that allow the appropriate verification of its		tracing facilities that allow the appropriate verification of its
	operation. The OPES architecture requires that tracing be feasible		operation. The OPES architecture requires that tracing be feasible
	on the OPES flow per OPES processor using in-band annotation. One		on the OPES flow per OPES processor using in-band annotation. One of
	of those annotations could be a URI with more detailed information on		those annotations could be a URI with more detailed information on
	the transformation that occurred to the data on the OPES flow.		the OPES services being executed in the OPES flow.
	Providing the ability for in-band annotation MAY require header		Providing the ability for in-band annotation MAY require header
	extensions on the application protocol that is used (e.g., HTTP).		extensions on the application protocol that is used (e.g., HTTP).
	However, the presence of an OPES processor in the data request/		However, the presence of an OPES processor in the data request/
	response flow SHALL NOT interfere with the operations of non-OPES		response flow SHALL NOT interfere with the operations of non-OPES
	aware clients and servers. The support of these extensions to the		aware clients and servers. The support of these extensions to the
	base protocol HTTP is not required by non-OPES clients and servers.		base protocol HTTP is not required by non-OPES clients and servers.
	OPES processors must obey tracing, reporting and notification		OPES processors MUST obey tracing, reporting and notification
	requirements set by the center of authority in the trust domain to		requirements set by the center of authority in the trust domain to
	which OPES processor belongs. As part of these requirements OPES		which OPES processor belongs. As part of these requirements OPES
	processor may be instructed to reject or ignore such requirements		processor may be instructed to reject or ignore such requirements
	that originate from other trust domains.		that originate from other trust domains.
	3. Security and Privacy Considerations		3. Security and Privacy Considerations
	Each data flow must be secured in accordance with several policies.		Each data flow MUST be secured in accordance with several policies.
	The primary stakeholders are the data consumer and the data provider.		The primary stakeholders are the data consumer and the data provider.
	The secondary stakeholders are the entities to which they may have		The secondary stakeholders are the entities to which they may have
	delegated their trust. The other stakeholders are the owners of the		delegated their trust. The other stakeholders are the owners of the
	callout servers. Any of these parties may be participants in the		callout servers. Any of these parties may be participants in the
	OPES flow.		OPES flow.
	These parties must have a model, explicit or implicit, describing		These parties MUST have a model, explicit or implicit, describing
	their trust policy; which of the other parties are trusted to operate		their trust policy; which of the other parties are trusted to operate
	on data, and what security enhancements are required for		on data, and what security enhancements are required for
	communication. The trust might be delegated for all data, or it		communication. The trust might be delegated for all data, or it
	might be restricted to granularity as small as an application data		might be restricted to granularity as small as an application data
	unit.		unit.
	All parties that are involved in enforcing policies must communicate		All parties that are involved in enforcing policies MUST communicate
	the policies to the parties that are involved. These parties are		the policies to the parties that are involved. These parties are
	trusted to adhere to the communicated policies.		trusted to adhere to the communicated policies.
	In order to delegate fine-grained trust, the parties must convey		In order to delegate fine-grained trust, the parties MUST convey
	policy information by implicit contract, by a setup protocol, by a		policy information by implicit contract, by a setup protocol, by a
	dynamic negotiation protocol, or in-line with application data		dynamic negotiation protocol, or in-line with application data
	headers.		headers.
	3.1 Trust Domains		3.1 Trust Domains
	The delegation of authority starts at either a data consumer or data		The delegation of authority starts at either a data consumer or data
	provider and moves to more distant entities in a "stepwise" fashion.		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.		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		The entities thus "colored" by the delegation are said to form a
	trust domain with respect to the original delegating party. Here,		trust domain with respect to the original delegating party. Here,
	"Colored" means that if the first step in the chain is the data		"Colored" means that if the first step in the chain is the data
	provider, then the stepwise delegation "colors" the chain with that		provider, then the stepwise delegation "colors" the chain with that
	data "provider" color. The only colors that are defined are the data		data "provider" color. The only colors that are defined are the data
	"provider" and the data "consumer". Delegation of authority		"provider" and the data "consumer". Delegation of authority
	(coloring) propagates from the content producer start of authority or		(coloring) propagates from the content producer start of authority or
	from the content consumer start of authority, that may be different		from the content consumer start of authority, that may be different
	from the end points in the data flow.		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		An OPES processor may be in several trust domains at any time. There
	is no restriction on whether the OPES processors are authorized by		is no restriction on whether the OPES processors are authorized by
	data consumers and/or data providers. The original party has the		data consumers and/or data providers. The original party has the
	option of forbidding or limiting redelegation.		option of forbidding or limiting redelegation.
	An OPES processor must have a representation of its trust domain		An OPES processor MUST have a representation of its trust domain
	memberships that it can report in whole or in part for tracing		memberships that it can report in whole or in part for tracing
	purposes. It must include the name of the party which delegated each		purposes. It MUST include the name of the party that delegated each
	privilege to it.		privilege to it.
	3.2 Callout protocol		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		The determination of whether or not OPES processors will use the
	measures that are described in the previous section during their		measures that are described in the previous section during their
	communication with callout servers depends on the details of how the		communication with callout servers depends on the details of how the
	primary parties delegated trust to the OPES processors and the trust		primary parties delegated trust to the OPES processors and the trust
	relationship between the OPES processors and the callout server. If		relationship between the OPES processors and the callout server. If
	the OPES processors are in a single administrative domain with strong		the OPES processors are in a single administrative domain with strong
	confidentiality guarantees, then encryption may be optional.		confidentiality guarantees, then encryption may be optional.
	However, it is recommended that for all cases that encryption and		However, it is recommended that for all cases that encryption and
	strong authentication be used.		strong authentication be used.
	If the delegation mechanism names the trusted parties and their		If the delegation mechanism names the trusted parties and their
	privileges in some way that permits authentication, then the OPES		privileges in some way that permits authentication, then the OPES
	processors will be responsible for enforcing the policy and for using		processors will be responsible for enforcing the policy and for using
	authentication as part of that enforcement.		authentication as part of that enforcement.
	The callout servers must be aware of the policy governing the		The callout servers MUST be aware of the policy governing the
	communication path. They must not, for example, communicate		communication path. They MUST not, for example, communicate
	confidential information to auxiliary servers outside the trust		confidential information to auxiliary servers outside the trust
	domain.		domain.
	A separate security association must be used for each channel		A separate security association MUST be used for each channel
	established between an OPES processor and a callout server. The		established between an OPES processor and a callout server. The
	channels must be separate for different primary parties.		channels MUST be separate for different primary parties.
	3.3 Privacy		3.4 Privacy
	Some data from data consumers is considered "private" or "sensitive",		Some data from data consumers is considered "private" or "sensitive",
	and OPES processors must both advise the primary parties of the their		and OPES processors MUST both advise the primary parties of their
	privacy policy and respect the policies of the primary parties. The		privacy policy and respect the policies of the primary parties. The
	privacy information must be conveyed on a per-flow basis.		privacy information MUST 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 servers must also participate in handling of private		The callout servers MUST also participate in the handling of private
	data, and they must be prepared to announce their own capabilities		data, and they MUST be prepared to announce their own capabilities
	and to enforce the policy required by the primary parties.		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		3.5 End-to-end Integrity
	Digital signature techniques can be used to mark data changes in such		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		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		consistent with the originating party's policy. This requires an
	inline manner of specifying policy and its binding to data, a trace		inline manner of specifying policy and its binding to data, a trace
	of changes and the party making the changes, and strong identities		of changes and the party making the changes, and strong identities
	and authentication methods.		and authentication methods.
	Strong end-to-end integrity can fulfill some of the functions		Strong end-to-end integrity can fulfill some of the functions
	required by "tracing".		required by "tracing".
	4. Summary		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		Although the architecture supports a wide range of cooperative
	transformation services, it has few requirements for		transformation services, it has few requirements for
	interoperability.		interoperability.
	The necessary and sufficient elements are specified in the following		The necessary and sufficient elements are specified in the following
	documents:		documents:
	o the OPES ruleset schema [6] which defines the syntax and semantics		o the OPES ruleset schema [5] which defines the syntax and semantics
	of the rules interpreted by a data dispatcher; and,		of the rules interpreted by a data dispatcher; and,
	o the OPES callout protocol (OCP) [7] which defines the requirements		o the OPES callout protocol (OCP) [6] which defines the requirements
	for the protocol between a data dispatcher and a callout server.		for the protocol between a data dispatcher and a callout server.
	References		Normative References
	[1] McHenry, S., et. al, "OPES Scenarios and Use Cases", Internet-		[1] McHenry, S., et. al, "OPES Scenarios and Use Cases",
	Draft TBD, May 2002.		Internet-Draft TBD, May 2002.
	[2] Floyd, S. and L. Daigle, "IAB Architectural and Policy		[2] Floyd, S. and L. Daigle, "IAB Architectural and Policy
	Considerations for Open Pluggable Edge Services", RFC 3238,		Considerations for Open Pluggable Edge Services", RFC 3238,
	January 2002.		January 2002.
	[3] Westerinen, A., Schnizlein, J., Strassner, J., Scherling, M.,		[3] Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L.,
	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 --		Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol --
	HTTP/1.1", RFC 2616, June 1999.		HTTP/1.1", RFC 2616, June 1999.
	[5] OPES working group, "OPES Service Authorization and Enforcement		[4] OPES working group, "OPES Service Authorization and Enforcement
	Requirements", Internet-Draft TBD, May 2002.		Requirements", Internet-Draft TBD, May 2002.
	[6] OPES working group, "OPES Ruleset Schema", Internet-Draft TBD,		[5] OPES working group, "OPES Ruleset Schema", Internet-Draft TBD,
	May 2002.		May 2002.
	[7] A. Beck et al., "Requirements for OPES Callout Protocols",		[6] A. Beck et al., "Requirements for OPES Callout Protocols",
	Internet-Draft http://www.ietf.org/internet-drafts/draft-ietf-		Internet-Draft http://www.ietf.org/internet-drafts/
	opes-protocol-reqs-00.txt, May 2002.		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		Authors' Addresses
	Abbie Barbir		Abbie Barbir
	Nortel Networks		Nortel Networks
	3500 Carling Avenue		3500 Carling Avenue
	Nepean, Ontario K2H 8E9		Nepean, Ontario K2H 8E9
	Canada		Canada
	Phone: +1 613 763 5229		Phone: +1 613 763 5229
	skipping to change at page 15, line 25 ¶		skipping to change at page 22, line 4 ¶
	Room 4F-513		Room 4F-513
	101 Crawfords Corner Road		101 Crawfords Corner Road
	Holmdel, NJ 07733		Holmdel, NJ 07733
	US		US
	Phone: +1 732 332 5983		Phone: +1 732 332 5983
	EMail: hofmann@bell-labs.com		EMail: hofmann@bell-labs.com
	Hilarie Orman		Hilarie Orman
	Purple Streak Development		Purple Streak Development
	EMail: ho@alum.mit.edu		EMail: ho@alum.mit.edu
	Reinaldo Penno		Reinaldo Penno
	Nortel Networks		Nortel Networks
	4555 Great America Parkway		2305 Mission College Boulevard
	Santa Clara, CA 95054		San Jose, CA 95134
	US		US
			Phone:
	EMail: rpenno@nortelnetworks.com		EMail: rpenno@nortelnetworks.com
	Gary Tomlinson		Appendix A. Acknowledgements
	The Tomlinson Group
	EMail: gary@tomlinsongroup.net		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.
	Appendix A. Acknowledgements		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.		The authors gratefully acknowledge the contributions of: John Morris,
	Rose, John Morris, Oskar Batuner, Mark Baker and Ian Cooper.		Mark Baker, Ian Cooper and Marshall T. Rose.
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