Afterword

The future is very hard to predict. Sometimes, technology is selected by the market which is severely sub-optimal, but at a large enough production scale, the difference becomes marginal. One can cite CD and VHS video as multimedia examples of just this. In other cases, such as TV standards, the market permits multiple standards to exist.

In the future, the firmament of network technologies will no doubt expand. We can see some interesting transmission technology for expansion of reach and capacity for the Internet in the emergence of cable modems, ADSL, and Satellite, as well as in mobile/wirelss access through GSM, LEO and Wavelan and IrDA access networks.

These will no doubt lead to certain interesting problems. Amongst those that we can say now that we have to solve are the following:

• Routing and QoS for mobile

• Routing and QoS for asymmetry (cable, adsl, satellite)

• quality of service for multicast sessions

• quantitative scaling for very large groups and very large numbers of groups potentially with high receiver and sender change rates.

• Simplicity/management of new services.

• Integration of legacy tv/telephone services.

• Possible web/mbone unification.