Scalable Content Distribution for Sparse Publish-Subscribe Systems Using the Object Management Group Real-Time Publish-Subscribe Protocol

Abstract

Publisher-side content based filtering methods and systems are provided to select which subscribers shall receive each data-message sent by a publisher using an Object Management Group (OMG) Real-Time Publish-Subscribe (RTPS) protocol. Methods and systems are provided for writer-side content based filtering and data distribution from a publisher to a plurality of subscribers using an Object Management Group (OMG) Real-Time Publish-Subscribe (RTPS) protocol. Methods and systems are provided for performing scalable content-based filtering and distribution from a publisher to a plurality of subscribers using to the Object Management Group (OMG) Real-Time Publish-Subscribe (RTPS) protocol.

What is claimed is: 
     
         1 . A method for performing publisher-side content based filtering to select which subscribers shall receive each data-message sent by a publisher using an Object Management Group (OMG) Real-Time Publish-Subscribe (RTPS) protocol, the method comprising the following computer-implemented method steps executable by one or more computers in a networked system:
 (a) having the publisher and a plurality of subscribers being able to communicate with each other using the RTPS protocol, wherein each of the subscribers uses a content filter to subscribe to a subset of the information published by the publisher;   (b) informing the publisher about the content filter used by each of the subscribers.   (c) the publisher determining via a lookup table the set of subscribers for which a data-message passes the corresponding subscriber content filter and then sending the data-message;   (d) the publisher evaluating the content filter of each of the subscribers on the data-message if the lookup table does not contain the set of subscribers to which the data-messages shall be sent; and   (e) the publisher updating the lookup table based on the result of the evaluation of the content-filter of each of the subscribers for a particular data-message.   
     
     
         2 . The method as set forth in  claim 1 , wherein the lookup table is a hash table. 
     
     
         3 . The method as set forth in  claim 1 , wherein the subscriber content filters involve only a subset of fields of the data-message. 
     
     
         4 . The method as set forth in  claim 3 , wherein the subscriber content filters involve only the fields marked as key attributes for the associated data-type. 
     
     
         5 . The method as set forth in  claim 3 , wherein the lookup table stores only the subset of the fields of the data-message involved in the subscriber filters.