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Receiver Driven Resource Reservation

The addition of multicast, multiple destination delivery of data to the Internet, has led to another refinement of the model: Receivers, rather than senders, decide which, and how much data they need.

In the radio and TV business, this has been known for sometime. In computer networks, where we wish to find information, it was less obvious. However, if we are disseminating information unsolicited, then the easiest way to cope with very large scale groups is to copy the TV model, and allow people simply to "tune in".

This does not mean that we cannot charge, or that we have no security.

These two aspects of the Internet are solved easily. The receivers are the people who specify which groups they join, and this information propagates through the routers, which are already supporting audio/video and data distribution at various quality levels, As they log the data, they simple add tags to say which users are currently receiving which information when. This also allows users who have less good equipment to specify a lower grade delivery, and the network can then save resources by only delivering a subset of the data (e.g. lower resolution video, or lower frame rate).

As to security, well, we simply encrypt all data at source, and only users with the correct key can decrypt the data they ask for. This relies on a more open attitude to privacy in networks than has been politically feasible for some time. However, if business is to take real advance of the information superhighway, then it is a requirement, no matter which actual technology is used to deliver the data.

Jon Crowcroft
Wed May 10 11:46:29 BST 1995