Level One Communications, Inc.

Intel Corporation

Michael A Sokol

Mark T Feuerstraeter

Kevin D Ketchum

A security device for use in communications network devices, such as multi-port repeaters, in local area networks to prevent eavesdropping by overwriting the data with an invalid symbol in the data communication packets transmitted to all unintended transceivers connected to the communications network device. Confidential or user sensitive information is not conveyed to the unintended transceivers since the invalid symbol is defined independent of the data. The invalid symbol unambiguously informs the unintended transceivers that the data in the data packet is invalid.

Method and apparatus employing an invalid symbol security jam for communications network security

A PHY having a media independent interface (MII) providing connections to a MAC or to another PHY is disclosed. The invention provides a mechanism for connecting a first PHY with a second PHY, wherein the PHY may act as the media access control side of the MII. The system includes a selection means for selecting the mode of operation for the PHY, a MII for providing a synchronous digital interface carrying un-encoded data over separate transmit and receive paths and a translation entity for generating output enables for controlling the flow of the data, wherein the translation entity establishes in response to mode being selected a first flow of data for connecting the PHY to a Media Access Control entity or a second flow of data for connecting the PHY to a second PHY. The translation entity muxes data and control signals based upon the mode selection. A translation synchronization entity is provided. The synchronization entity may includes a 10 Mbps synchronization entity and/or a 100 Mbps synchronization entity. The MII receives a transmit and receive clock from a second PHY when the PHY is connected to a second PHY, and the translation synchronization entity synchronizes the internal clocks and the MII transmit and receive clocks. An interface to a 10 or 100 Mbps repeater entity is provided wherein the interface maps a transmit data path from the translation entity to the repeater entity and receive data paths from the repeater entity to the translation entity.

Physical layer device having a media independent interface for

A system for integrating multiple repeaters into a single collision domain employs both analog and digital circuitry to convey system-wide collision information to repeaters thereby allowing seamless integration of multiple repeaters into multiple hubs without requiring additional drivers or external glue logic. One signal line (CFSL) within each hub is used to aggregate collision information within the hub. Further, only one signal line (CFSS) is used to aggregate collision information between hubs. This latter signal line in conjunction with two intra-hub signal lines (COLZ and SNGLZ) distributes system-wide collision information to all of the repeaters in all of the hubs.

Method and apparatus for integrating multiple repeaters into a single

Method and apparatus employing an invalid symbol security jam for

A method and apparatus for implementing a two-port Ethernet bridge using a semaphoring technique. The Ethernet bridge includes two MAC devices, a bus, a memory and a semaphoring scheme. The controllers include a first address which is used for indicating receipt of the packet and a second address which is used for indicating the transmission of the packet from the memory and for clearing of the memory location of the packet for further use. The receiving media access controller receives a data packet on a first port and the transmitting media access controller transmits the packet from the memory to a second port associated with the address of the intended user designated by the packet. The memory includes a dual-ring structure, with one ring used for receive traffic and the other ring used for transmit traffic. The MACs also include programmability for designating the type of packets that may be received. Thus, a particular address on the bus is uniquely designated to carry each message and the address on the bus is independent of the source of the message.

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Rancho Cordova, CA, United States of America

Michael A Sokol