Publish and subscribe topic mapping in a multicast environment
Original Publication Date: 2002-Oct-25
Included in the Prior Art Database: 2002-Oct-25
"Multicast" is a feature of IP-based networks which allows a message to be "broadcast" from one computer, and received by a number of other computers, where the sending computer only has to broadcast one copy of the message to the network, without any care for who (if anyone) is listening to receive it. This paper describes the use of a hashing function to hash topic names, in a publish/subscribe messaging environment, onto multicast addresses. Both the publisher and subscriber share this algorithm, and apply it consistently. A simple approach to the hash function satisfies a reasonable percentage of applications, and there is considerable advantage in having a "static" function which is "good enough", since this approach, which does not require out-of-band communication between publisher and subscribers, is a significant benefit. There is also scope for significant optimisation of the hashing function, making use of periodic feedback from subscribers about the topics they are subscribed to.