Scalable CSMA/CD repeater
First Claim
1. A network device, comprising:
- a plurality of ports;
a repeater unit including logic coupled to the plurality of ports which monitors activity on the plurality of portsi) to transmit a packet received without collision on one port to all other enabled ports in the plurality of ports, andii) to detect a collision between packets received on a set of ports in the plurality of ports, to identify the ports in the set of ports, and to issue commands to end stations coupled to ports in the set of ports to resolve the collision, the commands indicating to the ports in the set of ports to retry sending of a packet.
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Accused Products
Abstract
A scalable CSMA/CD repeater is based on polling and collision resolution logic, and slot time and interframe gap negotiation logic controlled by the repeater itself. The repeater based polling and collision resolution provides central control of the backoff and retry algorithm of each connected MAC unit. Thus, the MAC unit does not rely on random backoff mechanisms that significantly degrade performance of prior art systems. Furthermore, the retry by a MAC unit after a collision is managed by commands received from the collision resolution logic in the repeater. The repeater based collision resolution logic ensures that all ports involved in a collision have a fair opportunity to forward a packet without being blocked before enabling all the ports in the network to freely compete again. Furthermore, the negotiation of slot time and interframe gap allows for tight control of delay parameters in the network which are involved in collision resolution and scaling of the technology with increasing MAC unit processing speeds.
70 Citations
22 Claims
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1. A network device, comprising:
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a plurality of ports; a repeater unit including logic coupled to the plurality of ports which monitors activity on the plurality of ports i) to transmit a packet received without collision on one port to all other enabled ports in the plurality of ports, and ii) to detect a collision between packets received on a set of ports in the plurality of ports, to identify the ports in the set of ports, and to issue commands to end stations coupled to ports in the set of ports to resolve the collision, the commands indicating to the ports in the set of ports to retry sending of a packet. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A network device, comprising:
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a plurality of ports; a repeater unit including logic coupled to the plurality of ports which monitors activity on the plurality of ports i) to periodically issue commands to all enabled ports in the plurality of ports in parallel indicating clear to send status to end stations coupled to the plurality of ports, ii) to transmit a packet received without collision on one port to all other enabled ports in the plurality of ports, and ii) to detect a collision between packets received on a set of ports in the plurality of ports, to identify the ports in the set of ports, and to issue commands to end stations coupled to ports in the set of ports to resolve the collision, the commands assigning opportunities to the ports in the set of ports to send a packet without collision; and delay parameter negotiation logic, coupled to the repeater unit and the plurality of ports, which communicates with end stations coupled to the plurality of ports to determine delay parameters for use by the repeater unit to detect and resolve collisions.
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Specification