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
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Copyright Notice Copyright Notice
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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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