Network Working Group                                          A. Barbir
Internet-Draft                                           Nortel Networks
Expires: March 12, 18, 2004                               September 12, 18, 2003

              OPES processor and end points communications
                      draft-ietf-opes-end-comm-01
                      draft-ietf-opes-end-comm-02

Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

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Copyright Notice

   Copyright (C) The Internet Society (2003). All Rights Reserved.

Abstract

   This memo documents tracing requirements for Open Pluggable Edge
   Services (OPES).

Table of Contents

   1.    Introduction . . . . . . . . . . . . . . . . . . . . . . . .  3
   2.    OPES Domain and OPES System  . . . . . . . . . . . . . . . .  4
   3.    OPES Tracing . . . . . . . . . . . . . . . . . . . . . . . .  6
   3.1   What is traceable in an OPES Flow? . . . . . . . . . . . . .  6
   3.2   Requirements for Information Related to Traceable
         Entities?  . . . . . . . . . . . . . . . . . . . . . . . . .  7
   4.    Requirements for OPES processors . . . . . . . . . . . . . .  8
   5.    Requirements for callout servers . . . . . . . . . . . . . .  9
   6.    Privacy considerations . . . . . . . . . . . . . . . . . . . 10
   6.1   Tracing and Trust Domains  . . . . . . . . . . . . . . . . . 10
   7.    How to Support Tracing . . . . . . . . . . . . . . . . . . . 11
   7.1   Tracing and OPES System Granularity  . . . . . . . . . . . . 11
   7.2   Requirements for In-Band Tracing . . . . . . . . . . . . . . 12
   7.2.1 Tracing Information Granularity and Persistence levels
         Requirements . . . . . . . . . . . . . . . . . . . . . . . . 12
   7.3   Protocol Binding . . . . . . . . . . . . . . . . . . . . . . 13
   7.4
   8.    Tracing scenarios and examples Examples . . . . . . . . . . . . . . . 13
   8. . . . . . . . 14
   8.1   Single OPES Processor: Detailed Trace  . . . . . . . . . . . 14
   8.2   Single OPES Processor: Partial Trace . . . . . . . . . . . . 15
   8.3   Multiple OPES Processors: Full Trace . . . . . . . . . . . . 15
   8.4   Multiple OPES Processors: Partial Trace  . . . . . . . . . . 16
   9.    Optional Notification  . . . . . . . . . . . . . . . . . . . 14
   9. 18
   10.   IANA considerations  . . . . . . . . . . . . . . . . . . . . 16
   10. 20
   11.   Security Considerations  . . . . . . . . . . . . . . . . . . 17 21
         Normative References . . . . . . . . . . . . . . . . . . . . 18 22
         Informative References . . . . . . . . . . . . . . . . . . . 19 23
         Author's Address . . . . . . . . . . . . . . . . . . . . . . 19 23
   A.    Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 20 24
         Intellectual Property and Copyright Statements . . . . . . . 21 25

1. Introduction

   The Open Pluggable Edge Services (OPES) architecture [8] enables
   cooperative application services (OPES services) between a data
   provider, a data consumer, and zero or more OPES processors.  The
   application services under consideration analyze and possibly
   transform application-level messages exchanged between the data
   provider and the data consumer.

   The execution of such services is governed by a set of rules
   installed on the OPES processor.  The rules enforcement can trigger
   the execution of service applications local to the OPES processor.
   Alternatively, the OPES processor can distribute the responsibility
   of service execution by communicating and collaborating with one or
   more remote callout servers. As described in [8], an OPES processor
   communicates with and invokes services on a callout server by using a
   callout protocol.

   The work specify the requirements for providing tracing functionality
   for the OPES architecture [8]. This document specifies tracing
   mechanisms that the OPES architecture could provide that enable data
   provider application to detect inappropriate clinet client centric actions
   by OPES entities. The work focus on developing tracing requirements
   that can be used to fulfil fulfill the notification and Non-Blocking
   requirements [2].

   In the OPES architecture document [8], there is a requirement of
   relaying tracing information in-band. This work investigates this
   possibility and discusses possible methods that could be used to
   detect faulty OPES processors or callout servers by end points in an
   OPES flow.

   The document is organized as follows: Section 2 defines OPES Domain
   and OPES System. Section 3 discusses entities that are traceable in
   an OPES Flow. Sections 4 and 5 discuss tracing requirements for OPES
   systems and callout servers. Section 6 focus on Tracing and Trust
   Domains. Section 7 discusses how to support tracing and provides uses
   cases. Section 8 provides some examples of traces. Section 9 examines
   Optional Notofication. Notification.  Section 9 looks into IANA considerations.
   Section 10 examines security considerations.

2. OPES Domain and OPES System

   This sections clarifies the terms OPES system and OPES Domain [8].
   These terms are needed in order to define what is traceable in an
   OPES Flow [8].

   An OPES domain describes the collection of OPES entities that a
   single provider operates. OPES domains can be based on trust or other
   operational boundaries. All elements entities of an "OPES Domain" MUST be in
   the same trust domain. This would be independent of any specific OPES
   flow.
   Flow.

   An OPES system consists of a limited set of OPES entities, parts of a
   single or of multiple OPES operators domains, organized by (or on behalf) of
   either a data provider application or a data consumer application to
   perform authorized services on a given application message. Each OPES
   entity in an OPES system MUST be directly addressable on at the IP level
   by a data consumer application.

   An OPES system can be formed in a recursive manner. An OPES system
   can start with either a data provider application or a data consumer
   application (for a given message). The OPES system then includes any
   OPES entity trusted by (accepting authority from) an entity that is
   already in the OPES system. The trust and authority delegation is
   viewed in the context of the given application message.

   As implied by the above definition, some OPES entities in the system
   may
   MAY not participate in the processing of a given message.

   An OPES domain MUST not be an OPES sub-system. An OPES domain MUST
   require external resources to provide services. An OPES domain is a
   part of an OPES system belonging to a given operator. OPES domains
   have no incidence on the structure of an OPES system, but they may
   influence its organization for different reasons such as security,
   payment, quality of service, delivery parameters among others.

   In Figure 1 an OPES Flow is shown that traverses across various OPES
   Domains.
   Domains starting from a data provider application. A data consumer
   application MUST be able to recive receive tracing information on per
   message basis that enable it to determine the set of transformations
   that were perfomed performed on the data for a particular OPES Flow. The
   formation of an OPES flow Flow can be static or dynamic, meaning that the
   determination of which OPES Domains will participate in a given OPES
   Flow (per message basis) can be a function of business arrangements.

               +------------------------------------------+
               |             Data Consumer Application    |
               +------------------------------------------+
                                                     ^
                                                     |
               +-------------------------------------------+
               |                OPES System          | O   |
               |                                     |     |
               |     +-------------------------+     | P   |
               |     |        OPES Domain      |     |     |
               |     |      +---------------+  |     | E   |
               |     |      | OPES Entity   |  |     |     |
               |     |      +---------------+  |     | S   |
               |     |           .             |     |     |
               |     |           .             |     |     |
               |     |      +---------------+  |     | F   |
               |     |      |Callout Server |  |     |     |
               |     |      +---------------+  |     | L   |
               |     |                         |     |     |
               |     +-------------------------+     | O   |
               |                   .                 |     |
               |                   .                 | W   |
               |     +-------------------------+     |     |
               |     |        OPES Domain      |     |     |
               |     |      +---------------+  |     |     |
               |     |      | OPES Entity   |  |     |     |
               |     |      +---------------+  |     |     |
               |     |           .             |     |     |
               |     |           .             |     |     |
               |     |      +---------------+  |     |     |
               |     |      | OPES Entity   |  |     |     |
               |     |      +---------------+  |     |     |
               |     +-------------------------+     |     |
               |                                     v     |
               |    +-----------------------------------+  |
               |    |   Data Provider Application       |  |
               |    +-----------------------------------+  |
               |                                           |
               +-------------------------------------------+

                         Figure 1: OPES System

3. OPES Tracing

   Before discussing what is traceable in an OPES flow, it is beneficial
   to define what tracing means. Tracing is defined as the inclusion of
   necessary information within a message in an OPES flow that could be
   used to identify the set of transformations or adpatations adaptations that have
   been performed on its content in an OPES System before its delivery
   to an end point (the (for example, the data consumer application).

   o  OPES trace: application message information about OPES entities in
      an OPES System that adapted that message.

   o  OPES tracing: the process of including, manipulating, and
      interpreting an OPES trace in an OPES System.

   To emphasize, the above definition means that OPES tracing SHOULD be
   performed on per message basis. Trace format is dependent on the
   application protocol that is being adapted by OPES. Data consumer
   application can use OPES trace to infer the actions that have been
   performed by the OPES system.  The architecture document requires [8]
   that tracing be supported in-band.

   In an OPES System the task of providing tracing information, must
   take into account the following considerations:

   o  Providers may be hesitant to reveal information about their
      internal network infrastructure.

   o  Within a service provider network, OPES processors may be
      configured to use non-routable, private IP addresses.

   o  A Data consumer applications would prefer to have a single point
      of contact regarding the trace information.

   o  TBD

3.1 What is traceable in an OPES Flow?

   This section focuses on identifying the traceable entities in an OPES
   Flow.  Tracing information MUST be able to provide a data consumer
   application with useful information without tracing the exact OPES
   Processor or callout servers that adapted the data. It is up to the
   OPES service provider to have maintained appropriate internal
   detailed traces to find the answer to the data consumer applications
   inquiry.

   At the implementation level, for a given trace, an OPES entity
   involved in handling the corresponding application message is
   "traceable" or "traced" if information about it appears in that
   trace. OPES entities have different levels of traceability
   requirements. Specifically,

   o  An OPES system MUST add its entry to the trace.

   o  An OPES processor SHOULD add its entry to the trace.

   o  An OPES service SHOULD add its entry to the trace.

   o  An OPES entity MAY manage trace information from entities that are
      under its control. For example, an OPES processor may add or
      remove callout service entries in order to manage the size of a
      trace. Other considerations include:

      *  The OPES processor may MAY have a fixed configuration that enable
         it to respond to tracing inquires.

      *  The OPES processor may MAY insert a summary of the services that it
         controls. The summary can be used to respond to tracing
         inquiries.

      *  The OPES processor may MAY package tracing information related to
         the entities that it control based on the policy of a given
         OPES System.

   From an OPES context, a good tracing approach is similar to a trouble
   ticket ready for submission to a known address. The trace in itself
   is not necessarily a detailed description of what has happened. It is
   the resposibility responsibility of the operator to resolve the problems.

3.2 Requirements for Information Related to Traceable Entities?

   The requirements for information as related to entities that are
   terceable
   traceable in an OPES flow are:

   o  The privacy policy at the time it dealt with the message

   o  Identification of the party responsible for setting and  enforcing
      that policy

   o  Information pointing to a technical contact

   o  Information that identifies, to the technical contact, the OPES
      processors involved in processing the messag

   o  TBD message.

4. Requirements for OPES processors

   In order to facilitate compliance, the concept of an "OPES system"
   being traceable, requires that each OPES processor MUST support
   tracing.  Policy can be set that defines which domain has
   authorization to turn on tracing and its granularity.  An OPES
   provider can have its private policy for trace information, but it
   MUST support tracing mechanisms and it MUST reveal it's its policy.

   The requirements for OPES processors that are applicatble applicable to tracing
   are:

   o  Each OPES processor MUST belong to a single OPES Domain.

   o  Each OPES processor MUST have a Unique Identity in that Domain.

   o  Each OPES processor MUST support tracing, policy can be used to
      turn tracing on and.to and to determine granuality.

   o  TBD its granularity.

5. Requirements for callout servers

   If

   In an OPES system, it is the task of an OPES processor to add trace
   records to application messages, then messages. In this case, the callout servers
   that uses the OCP protocol [5] are not affected by tracing
   requirements. In order for an OCP protocol to be tracing neutral, the an
   OPES server SHOULD processor in an OPES system MUST be able to meet the following
   requirements:

   o  Callout services adapt payload regardless of the application
      protocol in use and leave header adjustment to OPES processor.

   o  OPES processor SHOULD be able  to trace it's own invocation and
      service(s) execution since they understand the application
      protocol.

   o  Callout servers  MAY be able to add their own OPES trace records
      to application level messages.

   o  TBD

6. Privacy considerations

6.1 Tracing and Trust Domains

   A trust domain may include several OPES systems and entities. Within
   a trust domain, there MUST be at least support for one trace entry
   per OPES system. Entities outside of that system may or may not see
   any traces, depending on domain policies or configuration. For
   example, if an OPES system is on the content provider "side",
   end-users are not guaranteed any traces. If an OPES system is working
   inside end-user domain, the origin server is not guaranteed any
   traces related to user requests.

7. How to Support Tracing

   In order to support tracing, the following aspects must be addressed:

   o  There MUST be a System Identifier that identify a domain that is
      employing an OPES system.

   o  An OPES processor MUST be able to be uniquely identified (MUST
      have an Identifier) within a system.

   o  An OPES processor MUST SHOULD add its identification to the trace.

   o  An OPES processor SHOULD add to the trace  identification of every
      callout service that received the application message.

   o  An  If the policy in an OPES system requires an OPES processor to turn
      tracing on, then the OPES processor MUST add to the trace
      identification of the
      "system/entity" "system or entity" it belongs to. "System"
      ID MUST make it possible to access "system" privacy policy.

   o  An OPES processor MAY group the above information for sequential
      trace entries having  the same "system/entity" ID. In other words,
      trace  entries produced within the same "system/entity" "system or entity"  MAY be
      merged/aggregated
      merged or aggregated into a single less detailed trace entry.

   o  An OPES processor MAY delegate trace management to  a callout
      service within the same "system/entity".

   TBD "system or entity".

7.1 Tracing and OPES System Granularity

   There are two distinct uses of traces. First, is to a trace SHOULD enable
   the "end (content producer or consumer) to detect OPES processor
   presence within end's trust domain. Such "end" should be able to see
   a trace entry, but does not need to be able to interpret it beyond
   identification of the trust domain(s).

   Second, the domain administrator SHOULD be able to take a trace entry
   (possibly supplied by an "end? as an opaque string) and interpret it.
   The administrator must be able to identify OPES processor(s) involved
   and may be able to identify applied adaptation services along with
   other message-specific information. That information SHOULD help to
   explain what OPES agent(s) entities were involved and what the actions that they did.
   performed. It may be impractical to provide all the required
   information in all cases. This document view a trace record as a
   hint, as opposed to an exhaustive audit.

   Since the administrators of various trust domains can have various
   ways of looking into tracing, they MAY require the choice of freedom
   in what to put in trace records and how to format them. Trace records
   should be easy to extend beyond basic OPES requirements. Trace
   management algorithms should treat trace records as opaque data to
   the extent possible.

   It is not expected that entities in one trust domain to be able to
   get all OPES-related feedback from entities in other trust domains.
   For example, if an end-user suspects that a served is service was corrupted by
   a callout service, then, there is no guarantee that the use user will be
   able to identify that service, contact its owner, or debug it _unless_ it, unless
   the service is within my its trust domain. This is no different from the
   current situation where it is impossible, in general, to know the
   contact person for an application on an origin server that generates
   corrupted HTML; and even if the person is known, one should not
   expect that person to respond to end-user queries.

7.2 Requirements for In-Band Tracing

   The OPES architecture [8] states that traces must be in-band. The
   support of this design specification goal is dependent on the specifics of the
   message application level protocol that is being used in an OPES
   flow. In-band tracing limits the type of application protocols that
   OPES can support. The details of what a trace record can convey is
   also dependent on the choice of the application level protocol.

   For these reasons, the this work will document documents requirements for application
   protocols that need to support OPES traces. However, the architecture
   does not prevent implementers of developing out-of-band protocols and
   techniques to address the above limitation.

7.2.1 Tracing Information Granularity and Persistence levels
      Requirements

   In order to be able to trace entities that have acted on an
   application message in an OPES flow, there may be requirements to
   keep information that is related to the following:

   o  Message-related informatio: information: All data that describes specific
      actions performed on the message SHOULD be provided with that
      message, as there is no other way to find message level details
      later. at
      a later stage.

   o  Session related information: Session level data MUST be preserved
      for the duration of the session. OPES processor is responsible for
      inserting notifications if session-level information changes.

   o  End-point related data: What profile is activated? Where to get
      profile details? Where to set preferences?

   o  TBD

7.3 Protocol Binding

   How

   The task of adding tracing is added information is application protocol-specific and protocol
   specific. Separate documents will be
   documented in separate drafts. address HTTP and other protocols.
   This work documents what tracing information is required and some
   common tracing elements.

7.4 Tracing scenarios and examples

   TBD

8. Optional Notification Tracing Examples

   This section examines IAB [2] considerations (3.1) and (3.2)
   regarding notification in an OPES architecture.

   Notification propagates in opposite direction provides some examples of tracing and cannot
   be attached to application messages that it notifies about. could be
   generated by an OPES System. The examples are based on HTTP [3] and
   use HTTP extension headers as given in [6]. In [6] trace entries are
   supplied using HTTP extension message headers. These headers are
   defined using #list constructs. A valid HTTP message may contain
   multiple entries of each header. In an OPES Systems, these headers
   MUST be used to represent the trace entries.

   In [6], the following HTTP extensions are defined:

      OPES-System = "OPES-System" ":" #trace-entry

      OPES-Processor = "OPES-Processor" ":" #trace-entry

      OPES-Service = "OPES-Service" ":" #trace-entry

      trace-entry = opes-agent-id *( ";" parameter )

      opes-agent-id = absoluteURI

8.1 Single OPES Processor: Detailed Trace

   This example consider the case of an OPES System consisting of a
   single OPES Processor that is capable of  locally performing three
   OPES services. A data consumer application may receive the following
   HTTP response message header after OPES adaptations have been
   applied:

      HTTP/1.1 200 OK

      Date: Wed, 15 Nov 1995 06:25:24 GMT

      Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT

      Content-type: application/octet-stream

      OPES-System: http://www.example-opes-systemA.com/
      opes?session=ac79a7901549f56

      OPES-Service: http:// www.example-opes-systemA.com /?sid=123

      OPES-Service: http:// www.example-opes-systemA.com /cat/?sid=124

      OPES-Service: http:// www.example-opes-systemA.com /cat/?sid=125
   In this example, the trace has identified the OPES System and all the
   OPES services that were performed on the data consumer application
   original request.

8.2 Single OPES Processor: Partial Trace

   In this example, the OPES System consisting of a two OPES Processor.
   Each Processor is capable of locally performing many OPES services. A
   data consumer application may receive the following HTTP response
   message header after OPES adaptations have been applied:

      HTTP/1.1 200 OK

      Date: Wed, 15 Nov 1995 06:25:24 GMT

      Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT

      Content-type: application/octet-stream

      OPES-System: http://www.example-opes-systemA.com/
      opes?session=ac79a7901549f56

      OPES-Service: http:// www.example-opes-systemA.com /?sid=123

      OPES-Service: http:// www.example-opes-systemA.com /cat/?sid=124 ;
      Mode = Aggregate

   In this example, several OPES services may be performed on the
   request. However, the trace has one entry that fully identifies one
   service and the other services are identified through a common ID.
   The OPES system is expected to be able to detail the other services
   when queried by the data consumer application.

8.3 Multiple OPES Processors: Full Trace

   In this example, the OPES System consisting of a two OPES Processors.
   Each processor is capable of locally performing two OPES services. A
   data consumer application may receive the following HTTP response
   message header after OPES adaptations have been applied:

      HTTP/1.1 200 OK

      Date: Wed, 15 Nov 1995 06:25:24 GMT

      Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT

      Content-type: application/octet-stream
      OPES-System: http://www.example-opes-systemA.com/
      opes?session=ac79a7901549f56

      OPES-Service: http:// www.example-opes-Service-Provider1.com /cat/
      ?sid=123

      OPES-Service: http:// www.example-opes-Service-Provider1.com /cat/
      ?sid=124

      OPES-Service: http:// www.example-opes-Service-Provider2.com /xxx/
      ?sid=111

      OPES-Service: http:// www.example-opes-Service-Provider2.com /xxx/
      ?sid=112

   In this example, the trace has identified the OPES System and all the
   OPES services that were performed on the data consumer application
   original request.

8.4 Multiple OPES Processors: Partial Trace

   In this example, the OPES System consisting of a two OPES Processors.
   Each processor is capable of locally performing several OPES
   services. A data consumer application may receive the following HTTP
   response message header after OPES adaptations have been applied:

      HTTP/1.1 200 OK

      Date: Wed, 15 Nov 1995 06:25:24 GMT

      Last-Modified: Wed, 15 Nov 1995 04:58:08 GMT

      Content-type: application/octet-stream

      OPES-System: http://www.example-opes-systemA.com/
      opes?session=ac79a7901549f56

      OPES-Service: http:// www.example-opes-Service-Provider1.com /cat/
      ?sid=123

      OPES-Service: http:// www.example-opes-Service-Provider1.com /cat/
      ?sid=124 ; Mode A

      OPES-Service: http:// www.example-opes-Service-Provider2.com /xxx/
      ?sid=111

      OPES-Service: http:// www.example-opes-Service-Provider2.com /xxx/
      ?sid=112 ; Mode B
   In this example, several OPES services may be performed on the
   request. However, the trace partially indicates the services that
   were performed. The OPES system is expected to be able to detail the
   other services when queried by the data consumer application.

9. Optional Notification

   This section examines IAB [2] considerations (3.1) and (3.2)
   regarding notification in an OPES architecture.

   Notification propagates in opposite direction of tracing and cannot
   be attached to the application messages that it notifies about.
   Notification can be done out-band and may require the development of
   a new protocol. The direction of data flow for tracing and
   notification are depicted in Figure 2.

                                      Notification
                +-----------------------------------------------
                |                                               |
                |                                               V
          +---------------+            +-------+       +---------------+
          |               |            |       |       | Data Provider |
          | Data Consumer | Tracing    | OPES  |<----->|  Application  |
          |  Application  |<-----------|       |       +---------------+
          +---------------+            +-------+
                                           ^
                                           |OCP
                                           |
                                           V
                                       +---------+
                                       | Callout |
                                       | Server  |
                                       +---------+

                      Figure 2: Notification Flow

   In [9] it was argued that Notification is an expensive approach for
   providing tracing information. However, the current work does not
   prevent an OPES System from publishing policy and specifications that
   allow Optional Notification. For example, an OPES System can adopt a
   mechanism that uses a flag that would allow a data consumer and a
   data provider application to signal to each other that they are
   interested to receive an explicit notification if an  OPES service is
   applied to a specific message. The value of this optional flag/field
   can be a URI that identifies notification method plus parameters. If
   a processor understands the method, it would be able to further
   decode the field and send a notification. The specification of  the
   field name and format for an  application protocol can be stated in
   the associated binding document. The details of the notification
   protocol is beyond the scope of this Working Group. document.

   For example, the following HTTP header:

   o

      OPES-Notify: URI *(pname=pvalue)

   Or,

   o

      My-OPES-Notify: foo=bar q=0.5

   can be used.

9.

10. IANA considerations

   TBD

10.

   This work does not require any IANA consideration since any actions
   will be addressed in [6].

11. Security Considerations

   TBD

   The security considerations for OPES are documented in [7]. This
   document is a requirement document for tracing and as such does not
   develop any new protocols that require security considerations.

Normative References

   [1]  McHenry, S., et. al,  A. Barbir et al., "OPES Scenarios and Use Cases", Cases and Deployment Scenarios",
        Internet-Draft TBD, May http://www.ietf.org/internet-drafts/
        draft-ietf-opes-scenarios-01.txt, Auguest 2002.

   [2]  Floyd, S. and L. Daigle, "IAB Architectural and Policy
        Considerations for Open Pluggable Edge Services", RFC 3238,
        January 2002.

   [3]  Fielding, R., Gettys, J., Mogul, J., Nielsen, H., Masinter, L.,
        Leach, P. and T. Berners-Lee, "Hypertext Transfer Protocol --
        HTTP/1.1", RFC 2616, June 1999.

   [4]  OPES working group, "OPES Service  A. Barbir et al., "Policy, Authorization and Enforcement
        Requirements",
        Requirements of OPES", Internet-Draft TBD, May 2002. http://www.ietf.org/
        internet-drafts/draft-ietf-opes-authorization-02.txt, February
        2003.

   [5]  OPES working group,  Rousskov, A., "OPES Ruleset Schema", Internet-Draft TBD,
        May 2002.

   [6]  A. Beck et al., "Requirements for OPES Callout Protocols", Protocol Core", Internet-Draft
        http://www.ietf.org/internet-drafts/
        draft-ietf-opes-protocol-reqs-03.txt, December 2002.
        draft-ietf-opes-ocp-core-01.txt, August  2003.

   [6]  Rousskov, A., "HTTP adaptation with OPES", Internet-Draft TBD,
        September 2003.

   [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.
        internet-drafts/draft-ietf-opes-threats-02.txt, February 2003.

   [8]  A. Barbir et al., "An Architecture for Open Pluggable Edge
        Services (OPES)", Internet-Draft http://www.ietf.org/
        internet-drafts/draft-ietf-opes-architecture-04, December  2002.

   [9]  A. Barbir et al., "OPES Treatment of IAB Considerations",
        Internet-Draft http://www.ietf.org/internet-drafts/
        draft-ietf-opes-iab-01.txt, February  2004.

Informative References

   [10]  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.

   [11]  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.

   [12]  "Hit Metering", RFC .

Author's Address

   Abbie Barbir
   Nortel Networks
   3500 Carling Avenue
   Nepean, Ontario  K2H 8E9
   Canada

   Phone: +1 613 763 5229
   EMail: abbieb@nortelnetworks.com

Appendix A. Acknowledgements

   TBD

   Several people has contributed to this work. Many thanks to: Alex
   Rousskov, Hilarie Orman, Oscar Batuner, Markus Huffman, Martin
   Stecher, Marshall Rose and Reinaldo Penno.

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