The receiver also recalculates the checksum, comparing result with value stored in frame. If the two checksums differ, some of the bits in the frame must have changed and the packet is discarded as having errors. Multicast addresses refer to a set of one or more stations. All machines process broadcast frames. Switched 802.3 LANs Can connect hosts to a hub switch.
Advantage is that stations use the same network interface card, but they can run at higher speeds.
Use of a special control frame called a token . Can only send a message by first capturing the token which passes between stations. No collisions because only one station at a time may hold the token. Different priority levels at each stations with each getting a fraction of the amount of time for the station. Periodically broadcast special tokens to allow new stations to enter the ring.