Open Pluggable Edge Services (OPES) Use Cases and Deployment Scenarios
RFC 3752
Network Working Group A. Barbir
Request for Comments: 3752 Nortel Networks
Category: Informational E. Burger
Brooktrout Technology, Inc.
R. Chen
AT&T Labs
S. McHenry
Individual Contributor
H. Orman
Purple Streak Development
R. Penno
Nortel Networks
April 2004
Open Pluggable Edge Services (OPES)
Use Cases and Deployment Scenarios
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract
This memo provides a discussion of use cases and deployment scenarios
for Open Pluggable Edge Services (OPES). The work examines services
that could be performed to requests and/or responses.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Types of OPES services . . . . . . . . . . . . . . . . . . . . 3
2.1. Services performed on requests . . . . . . . . . . . . . 3
2.1.1. Services intending to modify requests . . . . . 3
2.1.2. Services *not* intending to modify requests . . 4
2.2. Services performed on responses. . . . . . . . . . . . . 4
2.2.1. Services intending to modify responses . . . . . 4
2.2.2. Services *not* intending to modify responses . . 5
2.3. Services creating responses. . . . . . . . . . . . . . . 5
3. OPES deployment scenarios . . . . . . . . . . . . . . . . . . 5
3.1. Surrogate Overlays . . . . . . . . . . . . . . . . . . . 6
3.2. Delegate Overlays . . . . . . . . . . . . . . . . . . . 7
Barbir, et al. Informational [Page 1]
RFC 3752 OPES Scenarios April 2004
3.3. Enterprise environment . . . . . . . . . . . . . . . . . 8
3.4. Callout Servers . . . . . . . . . . . . . . . . . . . . 9
3.5. Chaining of OPES data filters and callout servers . . . 9
3.5.1. Chaining along the content path. . . . . . . . . 9
3.5.2. Chaining along the callout path. . . . . . . . . 9
4. Failure cases and service notification . . . . . . . . . . . . 10
5. Security Considerations. . . . . . . . . . . . . . . . . . . . 11
6. Informative References . . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12
8. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 12
9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 14
1. Introduction
The Open Pluggable Edge Services (OPES) [1] architecture 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 filtering 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 [6]
servers.
The document presents examples of services in which Open Pluggable
Edge Services (OPES) would be useful. There are different types of
OPES services: services that modify requests, services that modify
responses, and a special case of the latter, services that create
responses.
The work also examines various deployment scenarios of OPES services.
The two main deployment scenarios, as described by the OPES
architecture [1], are surrogate overlays and delegate overlays.
Surrogate overlays act on behalf of data provider applications, while
delegate overlays act on behalf of data consumer applications. The
document also describes combined surrogate and delegate overlays, as
one might find within an enterprise deployment.
The document is organized as follows: Section 2 discusses the various
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