Abstract: A switch of a computer network with a plurality of dual speed Ethernet client ports and at least one high speed Ethernet uplink port. The combined data rate of the Ethernet dual speed client ports has a maximum value which is higher than the data rate of the Ethernet uplink port. The Bandwidth Control limits the number of enabled Ethernet client ports so that the combined data rate of the enabled client ports substantially equals, or slights exceeds the data rate of the uplink port. In this way the speed and amount of switch memory can be minimized in the switch itself and the memory burden is divided among the clients. The dividing of the memory burden greatly reduces the worst case scenario and allows each client to individually chose the speed and amount of memory based on its own cost/benefit situation.

Abstract: A token ring network performs address to port mapping by taking advantage of the abilities of the port switched modules and the neighbor notification process, in order to perform address to port mapping on each individual module. Ring monitors are switched from an upstream side of a port to a downstream side of a port when the neighbor notification process enters the port domain. The processor on the module records all the addresses received on the downstream side of the port, when the neighbor notification process is in the domain of that port. If it appears that the neighbor notification process is in the domain of two adjacent ports, the present invention only records addresses from the most downstream of the two adjacent ports, since such a situation is an indication that the upstream ports do not conform to MAC protocol.

Abstract: Beacon recovery is performed separately on each module. After a module recognizes that a beacon condition has occurred, each module checks to determine if the defect or fault is on its module. If the defect is on the respective module, the module disconnects itself from the remaining modules in the network and transmits a beacon frame onto an upstream end of the group of stations on that module. Each port on the module is then tested to determine if the error lies in the corresponding station. This testing is based on the presence or absence of the beacon frame.