 predictable, unnoticeable delays, and regular delivery. It is mandatory for any LAN that is to carry video communication. Packet-switched Ethernet LANs are connectionless. This design is most effective with bursty or transaction-oriented data in which long lulls may occur between the transmissions of associated bits. For the sake of efficiency, all devices are connected to a common medium. Busy signals are never returned in this scenario. Instead, connectionless networks react to increased traffic by slowing down. When they do, users tend to take corrective action by twitching their cursor, reissuing commands and trying to open new applications. Of course, this only makes things worse. Eventually the congestion clears and throughput increases accordingly. Even though users become annoyed, delays are usually acceptable in networked text Packet-switched Networks and graphics applications. Real-time delivery is not critical to comprehension. To mediate congestion, frames of data are briefly buffered. Buffering is not an option for interactive video exchanges. Human protocols, which have evolved over millions of years, are highly sensitive to timing. Regular and sequential delivery is mandatory. Speech must be synched to lip movement. Pauses are more than distractions. Delays in excess of 325 milliseconds are debilitating. Unfortunately, when streaming media moves over Ethernet networks, pauses are the norm, not the exception. Because of Ethernet's resilience and adaptability, however, there are several different approaches to modifying existing Ethernet LANs to make them more suitable for multimedia traffic. When upgrading LANs, it is important to plan if multimedia communications will not be confined locally (which will usually be the case). The wide area network (which is increasingly also becoming Ethernet) must also be considered. Although intranets are very important, multimedia communications will not be confined to the populace of a single enterprise. Rather, an Internet or telephony (any-to-any) model, that