[August 14, 2001] OPES is about "extensible proxy services." The Open Pluggable Edge Services architecture (OPES) "defines how participating transit intermediaries can be extended to incorporate services executed on application data. The services are written to an open standard for use with the intermediaries." XML-based IETF Internet drafts from the working group include IRML (A Rule Specification Language for Intermediary Services) and OMML (OPES Meta-data Markup Language). The Intermediary Rule Markup Language (IRML) is "an XML-based language that can be used to describe service-specific execution rules. It allows clients, access providers, and content providers to specify when and how to execute intermediary services... Intermediary services are a new class of applications running on network edge intermediaries like caching proxies or dedicated application servers. These intermediary services can be executed on behalf of clients, access providers, or content providers. In order to control the execution of intermediary services, these parties provide service-specific rules that trigger services if rule conditions are met for incoming or outgoing messages." The OMML draft describes proxylets, which are "small fragments of code installed on Open Pluggable Edge Service (OPES) intermediary, and executed when condition(s) expressed using the Intermediary Rule Markup Language (IRML) match."
OPES escription: "Caching is a basic intermediary service, one that requires an understanding of at least a subset of application semantics by the cache server. Intermediaries may employ either local or remote ("callout") servers to perform a service, and as a result, the data may be diverted temporarily over a closed loop pathway different from the transit pathway. The purpose of this working group is to define the protocols for a broad set of services that facilitate efficient delivery of complex content or services related to application data. The advantage of standardizing these protocols is that the services can be re-used across vendor products without modifying the transit intermediaries or services. The architecture supports services that are either located on the transit intermediary or on callout servers. Protocols that connect the OPES service device and callout services must be defined. The ICAP protocol is one option for carrying HTTP headers and data to cooperating servers; the OPES framework will support other protocols to cooperating servers as they exist or become available. There are protocols and policies to define the applications that are plugged into the OPES server. The working group must define all the requirements that expose these as well..."
References:
- OPES web site
- IRML: A Rule Specification Language for Intermediary Services 'draft-beck-opes-irml-00.txt'; [cache, see also 'draft-beck-opes-psrl-00.txt']
- IRML XML DTD
- proposed IRML XML DTD with subsystem extensions.
- OMML: OPES Meta-data Markup Language 'draft-maciocco-opes-omml-00.txt'; [cache]
- OMML XML DTD
[September 10, 2001] "Quality of Service Extension to IRML." IETF INTERNET-DRAFT 'draft-ng-opes-irmlqos-00.txt.' July 2001. By Chan-Wah Ng, Pek Yew TAN, and Hong CHENG (Panasonic Singapore Laboratories Pte Ltd). "The Intermediary Rule Markup Language (IRML) is an XML-based language that can be used to describe service-specific execution rules for network edge intermediaries under the Open Pluggable Edge Services (OPES) framework, as described in "Extensible Proxy Services Framework" and "Example Services for Network Edge Proxies". This memo illustrates examples of employing the IRML for Quality of Service (QoS) policing and control, and suggests extensions to IRML for better QoS support. This memo begins in Section 2 by illustrating a few scenarios where QoS policing and control can be incorporated into the OPES intermediary. From there, a set of preliminary requirements for QoS extension to the IRML is drafted in Section 3. Section 4 proposed a set of QoS extension to the 'property' element defined in the IRML, and Section 5 presents some examples illustrating possible use of these extensions." [cache]
[September 10, 2001] "Sub-System Extension to IRML." IETF INTERNET-DRAFT 'draft-ng-opes-irmlsubsys-00.txt.' July 2001. By Chan-Wah Ng, Pek Yew TAN, and Hong CHENG (Panasonic Singapore Laboratories Pte Ltd). "The Intermediary Rule Markup Language (IRML) is an XML-based language that can be used to describe service-specific execution rules for network edge intermediaries under the Open Pluggable Edge Services (OPES) framework. This memo discusses the need for OPES framework to have different sub-systems in different deployment scenario, and proposes additions to IRML for a more flexible approach to supporting different sub-systems. Section 2 presents the motivation behind having sub-systems support in IRML. Section 3 proposes a set of QoS extension to the 'property' element defined in the IRML, and Section 4 presents some examples illustrating possible use of these extensions." See the revised proposed IRML DTD. [cache]
- OPES WG Charter
- Mailing list archives
