Cabletron Systems, Inc.

Digital Equipment Corporation

Enterasys Networks, Inc.

Shuki Perlman

Simoni Ben-Michael

Avraham Menachem

A repeater, which forwards data packets from a first Ethernet collision domain to a second Ethernet collision domain while filtering packets so as to eliminate unnecessary packets from being transmitted onto Ethernet networks, has a register for each port, where the register holds the address of a workstation from which the port last received a data packet. When a data packet addressed to that port is received by another port, the repeater asserts a signal line informing the other ports that the dat apacket may be ignored by them, and the addressed port receives the data packet for transmission onto the Ethernet collision domain connected thereto.

Adaptive addressing filtering

A repeater device for forwarding a data packet from a first Ethernet collision domain to a second Ethernet collision domain has a plurality of ports, each port for connection to an independent Ethernet collision domain, each port has an associated receive buffer and an associated transmit buffer, and there is a means for forwarding a data packet from the receive buffer of a receiving port to the transmit buffer of a transmitting port. A data packet received at the receiving port is then first stored in that port's the receive buffer, is forwarded to the transmit buffer of the transmitting port, and is then transmitted from the transmit buffer by the transmitting port.

Buffered repeater with independent ethernet collision domains

A repeater which introduces a minimum of delay in the transfer of a data packet from a source LAN to a destination LAN has an arbiter which grants access to a bus for a port to broadcast a received data packet onto the bus for loading the data packet into a transmit buffer for each outgoing port. The arbiter grants access only after all ports signal that their transmit buffers are ready to load the data packet from the bus. A transmit buffer signals that it is ready to be loaded at the passage of the collision window as it is transmitting a packet previously loaded into the transmit buffer. Accordingly, the transmit buffer is simultaneously transmitting the previously loaded packet and loading the new packet after the arbiter responds to the signal.

Method and apparatus for controlling transmission of data over a network

Automatic detection by a port of the type of device connected by a cable to the port is accomplished by transmitting a control packet by the device, where the control packet has a nonstandard format. The port examines received packets for the nonstandard format. Upon detection of a packet having the nonstandard format, the port recognizes that the source device of the packet is of a predetermined type which transmits control packets of the nonstandard format. Further, by choosing the nonstandard format so that typical forwarding devices will not forward the nonstandard packet, the port is assured that the source device is attached to the port by a cable. That is, by choosing a nonstandard packet which is not forwarded by a bridge or router, the port is assured that the packet has not been forwarded from a remote part of the network.

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Tzur Hadassa, Israel

Shuki Perlman