Cisco Technology, Inc.

Sanjay Aiyagari

Mick Henniger

Andrew George Harvey

Craig Alan Sharper

Hsuan-Chung Lee

Gregory Verissimo

Warren Meggitt

Gregory M Coffeng

A method and system for role-based access control enforced by an Operating System filesystem are provided. A file representing a resource is created and stored in the Operating System filesystem. A user requests access to the resource and provides user-identifying information and a resource identifier. An access identifier is created based on the user-identifying information and the resource identifier, and is formatted as the file attribute used by the Operating System to manage file access. A system call to the Operating System is made to perform an operation on the file representing the resource, where the system call uses the access identifier to gain access to the file. The user is granted access to the resource only if the operating system successfully performs the operation on the file representing the resource.

Role-based access control enforced by filesystem of an operating system

A method and apparatus are described for transmitting data in a network between first and second single-line digital subscriber line (SDSL) modems using a standard high data rate digital subscriber line (HDSL) frame format. The frame format includes at least one field in each data payload block, e.g., the F/Z bit field, for implementing a feature relating to one of the T1 and E1 transmission protocols. According to the invention, the at least one field is employed for transmission of selected payload data.

Method and apparatus for transmitting data in a public network

Methods and apparatus for transmitting and receiving data using framing circuitry designed to generate data frames of a first duration at a first data rate. According to the invention, data frames are generated and decomposed at lower data rates than the rate for which the framing circuitry was originally designed, i.e., the first data rate. The framing circuitry is programmed to organize a data stream into a sequence of data frames of the first duration or to decompose such data frames into a data stream. According to the invention, such a sequence of data frames corresponds to a selected one of a plurality of equivalent data rates. Each of the equivalent data rates are lower than the first data rate.

Methods and apparatus for transmitting data in a public network

An apparatus and method are provided for generating a plurality of data frames in a DSL modem configured as an HTU-C device using a single clock source. The technique of the present invention generates a data clock signal by combining a first clock signal provided by a clock source and a receiver overhead signal provided by framing circuitry for indicating the insertion of frame overhead bits into a data frame. The generated data clock signal has the characteristics such that, while the receiver overhead signal is inactive, the data clock signal is active at a frequency substantially equal to frequency of the first clock signal, and while the receiver overhead signal is active, the data clock signal is inactive. The result of this technique is that incoming data is clocked into the data frame at a data rate substantially equal to the frequency of the first clock signal only during time intervals when frame overhead bits are not being inserted into the one data frame. By using a single clock source to provide both the data rate and signaling rate, a reduction in cost, space, complexity, and power consumption of the HTU-C device may be achieved as compared to conventional devices.

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Santa Clara, CA, United States of America

Sanjay Aiyagari