Tibco Inc says the gating factor in the uptake of multicasting – transmitting a single packet of data over private networks or the Internet to all listeners, as opposed to sending the same message repeatedly – are ISPs, internet service providers. ISP business models rely on generating revenue from delivering large numbers of point-to-point messages. They aren’t set up – and in this respect aren’t served well by bridge and router vendors – to manage multicast traffic. Moreover, if thousands of individual messages are replaced by a single multicast message ISPs face a diminished revenue stream. At the moment ISPs don’t, as a rule, allow multicast traffic through their systems. Exceptions include Netcom On-line Communications Services Inc and Exodus Technologies Inc that have agreed to support it. Being an ISP is a low margin business, and to support multicasting ISPs must upgrade the systems that they have at each point of presence. Even if that’s just a small rack installed at a few hundred local telecommunications companies that’s an enormous capital cost. Currently Tibco bundles multicast messages and makes them acceptable to ISPs.