Occam Networks

Cisco Technology, Inc.

Mark Rumer

Robert Simon

Robert Arthur Land

David Eric Swanson

Michael D Savini

Marcus Prewarski

Kenneth Norton

William Sloan

Lisa Farr

Ronald Jeffries

A method and apparatus for receiving data from a network subscriber, wherein the data conforms to multiple protocols, converting the data into packets that conform to a single protocol of a single layer of the Open System Interconnection Model, and propagating the packets across a network.

Broadband loop carrier system

A local time of a broadband loop carrier terminal is synchronized to a network time received from a source external to the broadband loop carrier terminal by comparing the local time to the network time to generate an error offset, and adjusting the local time based on the error offset. The network time may be received in response to a Network Time Protocol (NTP) poll transmitted by the broadband loop carrier terminal. In some cases, the poll is transmitted over a communication medium using an asynchronous packet protocol, such as Ethernet or TCP/IP. In one embodiment, the local time is based on the output of a local oscillator (e.g., a voltage controlled oscillator), the frequency of which may be adjusted using control logic which uses a filtered version of the error offset along with a factory calibration and/or temperature compensation to produce a control voltage to control the oscillator frequency.

System and method for synchronization of devices across a packet network

A method and apparatus for packetizing data framed as a TDM stream as an Ethernet packet. In an embodiment, the data is packetized into an Ethernet frame having a header which includes information which indicates an appropriate time at which to write the data into an outbound TDM stream.

Ethernet based TDM switch

A telecommunications network having a ring topology overlaid with an Ethernet. An add/drop multiplexer (ADM) employing wave division multiplexing (WDM) hardware is implemented at each node of a multi-node fiber-based network. The ADM contains a robust protection scheme for reliability. The WDM allows the data traffic of the incumbent network, for example, a SONET network, to be carried over one or more frequencies while the data traffic of one or more packet-based networks may be carried over one or more other frequencies. Each ADM has protection switches, for example, micro-electromechanical switches. The protection switches provide a no-load bypass capability. A failed node can be shunted from the ring, allowing the Ethernet data to bypass the node uninterrupted. The switches also provide a self-test capability. The ADM interfaces can be checked by coupling the receiving path and the transmission path. This allows the ADM transceivers to communicate with each other.

Optical ethernet overlay for loop topology network

A communication bus snooper switch includes an inbound cell queue coupled to receive ATM cells from a number of ATM physical layer interfaces across a common inbound bus. An out-bound cell queue (which may be the same queue as the inbound cell queue when a dual port queue is used) is coupled to provide the ATM cells to separate ATM termination points according cell address information across separate out-bound busses. Each of the out-bound busses is associated with one of the ATM termination points. The snooper switch is configured to operate as an ATM bus master when communicating with the physical layer interfaces and as a ATM bus slave when communicating with the ATM termination points. During transmit operations, cells from the various ATM termination points are queued in corresponding transmission cell queues within the snooper switch and, thereafter, provided to the ATM physical layer interfaces according to an arbitration scheme implemented at the snooper switch.

ATM utopia bus snooper switch

A protection device includes a substrate capable of suppressing electromagnetic fields, with a channel formed therein, a current dependent circuit interrupter disposed inside the channel, and voltage management circuitry coupled to the substrate. The voltage management circuitry is electrically coupled to the current dependent circuit interrupter so as to form a crowbar circuit in the presence of overvoltage or undervoltage conditions as determined according to a reference voltage.

Integrated telephony subscriber line protection and filter device

A system having a free space optical transmission capability for data and/or control interconnection is described. Switch cards, having corresponding pairs of laser transmitters and photodetectors are placed in a chassis, at each end, facing each other. Each laser transmitter/photodetector (LTPD) pair of one switch card is targeted to a corresponding photodetector/laser transmitter (PDLT) pair of the other. System line cards have a LTPD pair on one side and a PDLT pair on the other side. A line card is positioned in the chassis so that the LTPD pair is aligned with a corresponding PDLT pair on one switch card and the PDLT pair is aligned with a corresponding LTPD pair on the other switch card. The line card may, therefore, communicate with either switch card. The line cards contain apertures so that communication between other line cards and the switch cards is not obstructed.

Free space optical &ldquo;backplane&rdquo; (FSO)

An optical add/drop multiplexer to be tuned locally or remotely, to compensate for drift in operation, and to facilitate installation or replacement at remote terminals.

Tunable optical add-drop multiplexer

A frame relay communications network consists of a number of interconnected nodes. The network nodes include segmentation and reassembly device for fragmenting variable length frames of user data into packets of a predefined length. A preferred embodiment uses ATM AAL5 segmentation and reassembly to construct cells. Header and trailer information is added to each of the cells for transport across the frame relay network.

ATM cells within frame relay technology

A network switch includes a plurality of cell processing units coupled together via a switch bus. In a preferred embodiment, the switch bus supports the peripheral component interconnect (PCI) bus protocol. Each cell processing unit includes a segmentation and reassembly unit (SAR), a RISC processor, a port processor, and a bus control unit. The SAR generates cells from frames of data stored in memory and transfers those cells to a destination mailbox in response to commands from from the RISC processor. The SAR assembles a cell within an internal register by combining cell header information with payload data read from memory. Once a cell has been assembled, it is sent to the bus controller for transmission across the switch bus to an address given by a mailbox number. Cells are transferred across the switch bus using a PCI burst write to the mailbox. A reassembly function gathers 48-byte cells into one or more larger output buffers. Cell reassembly is triggered by another RISC processor command. During reassembly, cell header information is discarded and the data payload bytes are read to an internal buffer within the SAR. The payload data is then written to a memory location pointed to by a buffer memory pointer. The switch bus 14 is also used for the transfer of control information between configuration registers of the cell processing units 12.

ATM switch with integrated system bus

A transport layer protocol for a compressed voice, facsimile and modem data includes a voice packetization sublayer; a voice transport sublayer; and a voice payload segmentation and reassembly sublayer. The voice payload segmentation and reassembly sublayer breaks up user data packets into segments. Each segment includes a header and a payload data unit. Voice data segments have payloads made up of voice data. Signaling payloads are made up of op codes, which define the type of signaling message, and related operands.

Growing community of inventors

Santa Barbara, CA, United States of America

Mark Rumer