Extreme Networks, Inc.

Steve Haddock

Michael Yip

Herb Schneider

A method and system is provided in which MAN traffic is segregated at a customer and a provider domain level. A switch at the edge of the MAN encapsulates a data packet in a new header, which is used to specify the customer domain tags. The data packet is encapsulated further in another new header, which is used to specify new VMAN tags. The nested encapsulation is repeated as necessary until the data packet is forwarded to a remote switch at the edge of the MAN in accordance with the VMAN configuration or the source and destination address in the original data packet. The remote switch strips the VMAN tags from the data packet, and forwards the stripped data packet to the receiving customer domain as specified in the customer domain tag.

Method and system for VMAN protocol Layer-2 packet nested encapsulation

Method and system for VMAN protocol

A repeater that prevents a node involved in a collision from detecting that the collision occurred, and transmits the data packet received from that node to all other nodes connected to the repeater. The repeater accomplishes this by repeating the data packet received from that node during the collision, and discarding the data packets received from other nodes, thereby allowing a valid data packet to traverse the repeater and all communication medium segments attached thereto. The repeater maintains a count of the collisions and retransmission attempts experienced by each node since that node's last successful data packet transmission. The count is used to prioritize which of the nodes involved in a subsequent collision will be allowed to continue to transmit. Such prioritization reduces any disparity in the number of retransmission attempts experienced by each node, thereby reducing the likelihood of a node dropping a data packet as occurs when the maximum number of retransmission attempts allowed for such node is reached.

Method and apparatus for arbitrating data transmission in a CSMA/CD LAN

An improved repeater or hub in a CSMA/CD based LAN that provides deterministic access to a shared communication medium for a limited number of nodes and improves the nondeterministic access latency for up to the maximum number of nodes allowed to be coupled to the repeater without requiring any modification to the adapter in each of the nodes. The repeater prevents a node involved in a collision from detecting that the collision occurred, and transmits the data packet received from that node to all other nodes connected to the repeater. The repeater accomplishes this by repeating the data packet received from that node during the collision, and discarding the data packets received from other nodes, thereby improving the performance of a CSMA/CD LAN by allowing a valid data packet to traverse the repeater and all communication medium segments attached thereto. When selecting which node shall continue transmitting, the repeater gives priority to the node with the currently highest number of outstanding packet retransmission attempts.

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Los Gatos, CA, United States of America

Steve Haddock