Method for sending and receiving a Boolean function over a network

• US 7,117,270 B2
• Filed: 07/19/2002
• Issued: 10/03/2006
• Est. Priority Date: 08/15/2001
• Status: Expired due to Fees

• Current Assignee: Precache Incorporated
• Original Assignee: Precache Incorporated
• Inventors: Rosenblum, David S.
• Primary Examiner(s): Vaughn, Jr., William C.
• Assistant Examiner(s): MESFIN, YEMANE
• Application Number:
  US10/199,439
• Publication Number:
  US 20030154302A1
• Time in Patent Office: 1,537 Days
• Field of Search: 709238-240, 709/242, 709/245, 709/246
• US Class Current: 709/238
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: H04L 45/302 Route determination based on requested QoS
• CPC Class Codes: H04L 45/306 Route determination based on the nature of the carried application
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context

Abstract

Conversion of subscription predicates for transmission in a publish-subscribe network. Subscriptions include Boolean-valued predicates defining content desired by a subscriber. An agent application converts the predicates into a suitable form for transmission to routers in a network core. The routers process the predicates into filter tables or data structures for use in content-based routing, which involves applying attributes in received packets to the filters. The agent also receives content corresponding with subscriptions and calls applications for presenting the content to a subscriber.

Claims

1. A method for transmitting predicates in a publish-subscribe network, comprising:

receiving an expression including Boolean-valued predicates relating to a subscription;

encoding the expression into a message for transmission in the network for use in content-based routing wherein the encoding step includes converting the expression into a corresponding disjunctive normal form, converting the disjunctive normal form into a corresponding sequence of bit-string encodings of attribute tests, simplifying AND expressions in the disjunctive normal form to contain range filters and membership tests and translating not-equal parameters in the expression to positive form; and

transmitting the message to at least one router in a network core in order to provide content-based routing for the subscription.

2. The method of claim 1 wherein the encoding step includes converting the expression into a flat message format.

3. The method of claim 1 wherein the receiving step includes receiving for the predicates conjunction, disjunction, or negation terms.

4. The method of claim 1, further including:

receiving the subscription; and

creating the expression from the subscription.

5. The method of claim 1, further including parsing the expression in order to detect errors in the subscription.

6. The method of claim 1, further including storing the expression in a data structure.

7. An apparatus for transmitting predicates in a publish-subscribe network, comprising:

a receive module for receiving an expression including Boolean-valued predicates relating to a subscription;

an encode module for encoding the expression into a message for transmission in the network for use in content-based routing, wherein the encode module includes a module for converting the expression into a corresponding disjunctive normal form, a module for converting the disjunctive normal form into a corresponding sequence of bit-string encodings for attribute tests, a module for simplifying AND expressions in the disjunctive normal form to contain range filters and membership tests and a module for translating not-equal parameters in the expression to positive form; and

a transmit module for transmitting the message to at least one router in a network core in order to provide content-based routing for the subscription.

8. The apparatus of claim 7, wherein the encode module includes a module for converting the expression into a flat message format.

9. The apparatus of claim 7, wherein the receive module includes a module for receiving for the predicates conjunction, disjunction, or negation terms.

10. The apparatus of claim 7, further including:

a module for receiving the subscription; and

a module for creating the expression from the subscription.

11. The apparatus of claim 7, further including a module for parsing the expression in order to detect errors in the subscription.

12. The apparatus of claim 7, further including a module for storing the expression in a data structure.