ITU-T Study Group 15 Update for IEEE 802.1 Glenn Parsons [email protected] [email protected].
Recap of P: Message Processing Language Presented by Abbie Barbir [email protected].
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Transcript of Recap of P: Message Processing Language Presented by Abbie Barbir [email protected].
![Page 2: Recap of P: Message Processing Language Presented by Abbie Barbir abbieb@nortelnetworks.com.](https://reader036.fdocuments.in/reader036/viewer/2022082612/56649f305503460f94c4a257/html5/thumbnails/2.jpg)
August 3, 2004 2
P: Message Processing Language
• P is a simple configuration language designed for specification of message processing instructions (service) at application proxies– P can be used to instruct an intermediary on how to
manipulate the application message that is being processed
• Original draft work was submitted by– Alex Rousskov ([email protected]) and – Andre Beck ([email protected])• draft-ietf-opes-rules-p-02
![Page 3: Recap of P: Message Processing Language Presented by Abbie Barbir abbieb@nortelnetworks.com.](https://reader036.fdocuments.in/reader036/viewer/2022082612/56649f305503460f94c4a257/html5/thumbnails/3.jpg)
August 3, 2004 3
P Design Objectives
• P language primary objective is to express statements similar to:
– If message meets criteria C,
– Then apply service S;
• P programs mostly deal with formulating message-dependent conditions and executing authorized services
• P design is meant to be applicable for a variety of similar intermediary configuration tasks such as
– Access Control List (ACL) specification
– Message routing in proxy meshes or
– Load-balancing environments
![Page 4: Recap of P: Message Processing Language Presented by Abbie Barbir abbieb@nortelnetworks.com.](https://reader036.fdocuments.in/reader036/viewer/2022082612/56649f305503460f94c4a257/html5/thumbnails/4.jpg)
August 3, 2004 4
Characteristics of “P”• P is a single-assignment, lazy evaluation, strongly typed
functional programming language• Centered around the concept of an “object”, similar to objects
of object-oriented languages• An object is, essentially, a piece of data or information• Value of an object is indistinguishable from the object itself• Object type is defined by the semantics of applicable
operations and manipulations• Almost everything in P is an object, even a piece of code• General approach is application protocol agnostic– Supports loadable modules for adding support of (existing
and new) application protocols
![Page 5: Recap of P: Message Processing Language Presented by Abbie Barbir abbieb@nortelnetworks.com.](https://reader036.fdocuments.in/reader036/viewer/2022082612/56649f305503460f94c4a257/html5/thumbnails/5.jpg)
August 3, 2004 5
Open Issues/Problems
• What (message) information can the P interpreter access, i.e. what information can be part of a rule condition?
• For example:
– Complete message (including message body),
– Meta-information only (e.g. HTTP headers only),
– Where to draw the line?
– Does the WG have to specify this?
• Should the WG document an HTTP module for P?
– If yes, in what document?
• Should the WG define interfaces between P interpreters and module suppliers and/or callout services?
– How do services return results?
![Page 6: Recap of P: Message Processing Language Presented by Abbie Barbir abbieb@nortelnetworks.com.](https://reader036.fdocuments.in/reader036/viewer/2022082612/56649f305503460f94c4a257/html5/thumbnails/6.jpg)
August 3, 2004 6
Q&A