3com Corporation

3com Technologies

Nigel Horspool

David J Law

Paul J Moran

Tadhg Creedon

Justin A Drummond-Murray

Quang T Tran

Nicholas Mark Stapleton

Terence D Lockyer

Patrick Michael Overs

Paul Cramphorn

Pauric O'Callaghan

A network communications device is arranged to have a fast throughput of data packets. This is achieved by recognising that, in protocols such as Ethernet, the first symbols in a data packet do not carry any data and therefore do not necessarily require to be properly carried through a communications hub. Rather, a known number of symbols are discarded from the start of a packet on receipt and replaced on re-transmission. This discarding reduces the reception delays particularly in bussed-architecture repeaters where bus arbitration must take place for each received packet.

Network communication device

A data connection between two network stations such as an Ethernet hub and an end station which are both capable of exchanging data at the higher of two rates, the higher rate being selected by an auto-negotiation process, is monitored for the occurrence of error represented by a symbol representing the start of a data packet immediately followed by an idle symbol. The rate of occurrence of such errors is compared against a threshold and the speed of the data connection is downgraded to the lower rate.

Monitoring of connection between an ethernet hub and an end station

A method of operating a repeater for a packet-based data transmission system wherein the repeater has a receiving port associated with a buffer whereby packets received at the port are temporarily stored before they are onwardly transmitted and wherein the repeater performs a contention resolution process such that if an attempted onward transmission of a packet is prevented by virtue of contention with a prior or an existing transmission, a subsequent attempt at transmission of that packet is delayed for a time which is likely to be substantially greater than a selected minimum time. The method includes examining a received packet to determine whether the packet is a multi-media packet, and giving the packet a higher priority in the contention resolution process such that if the packet is not transmitted onwardly owing to contention with a prior transmission, a fresh attempt at transmission of the packet is made on the expiry of the selected minimum time.

Method for transmitting multimedia packet data using a contention-resolution process

The occurrence of collision and activity in a computer network is indicated by activation of a visual indication device. The device is activated for periods which are longer than the actual periods of collision and activity to permit the human eye to register the visual indications. This is particularly useful for high speed networks where the periods of collision and activity may be very brief.

Network hub activity display

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Tervuren, Belgium

Nigel Horspool