Cisco Technology, Inc.

Brent K Parrish

Werner E Niebel

Ronald A McCracken

John J Fernald

Michael J Taylor

Lee C Stevens

John P Barry

Christopher A Metildi

Michael P Colton

According to one embodiment, a telecommunications device includes a bus. A first controller coupled to the bus is operable to generate first pulses for communication using the bus. A second controller coupled to the bus is operable to generate second pulses synchronized with the first pulses for communication using the bus. A card coupled to the bus is operable to receive the first and second pulses, generate internal pulses synchronized with the first and second pulses, compare at least one internal pulse with at least one first pulse to detect a loss of synchronization, and indicate this loss of synchronization to allow the second controller to determine a failure of the first controller.

Frame synchronization and fault protection for a telecommunications device

In one embodiment, a switching system includes a backplane and multiple cards that each support multiple ASIC devices. Each ASIC device is associated with a subset of the network interfaces associated with the switching system. At least one ASIC device on a card may communicate switched data to an outgoing network interface associated with the card. Remaining ASIC devices on the card may communicate switched data to one or more other cards, using the backplane, for communication to one or more outgoing network interfaces associated with the other cards. In another embodiment, a device for switching data from a first bus to a second bus in a TDM switching system is provided. In another embodiment, a method for switching data between a plurality of network interfaces in a switching system is disclosed.

TDM switching system and ASIC device

According to one embodiment, a telecommunications device includes a bus and a controller coupled to the bus that generates a system clock signal according to a first reference clock signal and communicates the system clock signal using the bus. The controller detects a loss of the first reference clock signal and, in response, continues generating the system clock signal, switches from the first reference clock signal to a second reference clock signal if the second reference clock signal is acceptable, and generates the system clock signal according to the second reference clock signal.

Clock synchronization and fault protection for a telecommunications device

A telecommunications device includes a sender coupled to a local area network. The sender generates a message packet including an arbitration code and a data packet and communicates a first value of the arbitration code using the network. The sender determines a network value and compares the first value with the network value to determine whether the sender may communicate the data packet using the network. The arbitration code may further include a message priority code and a sender address. In another embodiment, the message packet further includes a destination code according to which the sender communicates the data packet as a point-to-point, multi-cast, or broadcast message.

Local area network and message packet for a telecommunications device

In one embodiment, a telecommunications device includes a synchronization bus and a controller coupled to the bus that generates a system clock signal according to a primary reference clock signal and communicates the system clock signal using the bus. The controller detects a loss of the primary reference clock signal and, in response, continues generating the system clock signal, determines acceptability of a secondary reference clock signal, switches from the primary reference clock signal to the secondary reference clock signal if the secondary reference clock signal is acceptable, and in response to the switch generates the system clock signal according to the secondary reference clock signal.

In another embodiment, an ASIC device includes a first RAM that stores a code for each of multiple first time slots. Each code is combined with corresponding data from a first bus to specify a previously stored operation. A second RAM receives the combined data and code for each first time slot and applies the specified operation for each first time slot to generate modified data for each first time slot. A third RAM stores information specifying a second time slot to correspond to each first time slot and communicates the information for each second time slot as an address. A fourth RAM stores the modified data for a previous frame and the modified data for a current frame, locates the modified data for each first time slot of the previous frame according to the address, and communicates the modified data for each time slot of the previous frame to a second bus in the corresponding second time slot while the modified data for the current frame is being stored.

A telecommunications device includes an event initiation bus, at least one card coupled to the bus that can execute an event, and at least one controller also coupled to the bus that can communicate an event code value to the card using the bus. The event code value indicates the event is to be executed. The controller determines an event code value from the bus, compares the communicated event code value with the determined event code value, and transmits an event strobe signal to the card using the bus if the communicated event code value matches the determined event code value. The event strobe signal enables execution of the event and the card executes the event in response to the event code value and the event strobe signal. In a particular embodiment, the device is a switching unit having a high availability backplane environment.

Event initiation bus and associated fault protection for a telecommunications device

A telecommunications device includes a synchronization bus. A first controller coupled to the bus generates first pulses and communicates the first pulses using the bus. A second controller coupled to the bus generates second pulses synchronized with the first pulses and communicates the second pulses using the bus. A card also coupled to the bus receives the first and second pulses and generates internal pulses synchronized with the first and second pulses. The card compares at least one internal pulse with at least one first pulse to detect a loss of synchronization between the internal pulse and the first pulse. The card indicates this loss of synchronization and the second controller may determine a failure of the first controller in response to at least the indication from the card. In a particular embodiment, the device is a switching unit with a high availability backplane environment, the first and second pulses are frame pulses having time slots, and the loss of synchronization is associated with a framing error.

A telecommunications device includes a synchronization bus and a controller coupled to the bus. The controller selects a primary reference clock signal from among a plurality of reference clock signals, generates a first system clock signal according to the primary reference clock signal, and communicates the system clock signal using the bus. The controller detects a loss of signal associated with the primary reference clock signal and, in response, enters holdover mode. The controller continues generating the first system clock signal while in holdover mode and determines the acceptability of a secondary reference clock signal also selected from among the plurality of reference clock signals. The controller performs a switchover from the primary reference clock signal to the secondary reference clock signal if the secondary reference clock signal is acceptable and, in response to the switchover, generates the first system clock signal according to the secondary reference clock signal. In one embodiment, a card coupled to the bus detects and indicates a loss of signal associated with the first system clock signal. A second controller determines a failure of the controller in response to at least the indication from the card. In a particular embodiment, the device is a switching unit having a high availability backplane environment.

A telecommunications device includes a backplane having an associated high availability backplane environment. A transition card coupled to the backplane helps transition a standards-based card supporting a Peripheral Component Interconnect (PCI) administrative bus into the high availability backplane environment. The transition card may also help transition either a Computer Telephony or a Serial Telephony serial data bus into the high availability backplane environment. In a more particular embodiment, the transition card may support a control bus, a synchronization bus, a reset bus, an isolate bus, and a power bus that each support at least one high availability characteristic not associated with the PCI bus. In another more particular embodiment, the transition card may provide at least some redundancy, hot insertion, fault detection, fault isolation, and fault recovery capabilities not associated with the PCI bus.

Transitioning a standards-based card into a high availability backplane environment

In one embodiment, in a switching system, an ASIC device on a card coupled to a backplane communicates switched data to an outgoing network interface for the card without using the backplane, and remaining ASIC devices on the card communicate switched data, to other cards using the backplane for communication to outgoing network interfaces for the other cards. In another embodiment, an ASIC device includes a RAM storing a code for each first slot to combine with corresponding data from a first bus to specify an operation, a RAM applying the operation to generate modified data for each first slot, a RAM communicating as an address information specifying a second slot to correspond to each first slot, and a RAM locating the modified data for each first slot of a previous frame according to the address and communicating this modified data to a second bus in the corresponding second slot while the modified data for a current frame is being stored.

A telecommunications device includes a protection bus, at least one protected card, and an I/O module for the protected card. The I/O module is coupled to the protected card and the protection bus and communicates data between the protected card and an associated network interface. The device also includes at least one protection card and a protection I/O module for the protection card. The protection I/O module is coupled to the protection card and to the protection bus and is capable of assuming at least some responsibilities of the protected card in response to a failure of the protected card. The protection I/O module will then communicate the data between the protection card and the I/O module for the protected card using the protection bus. The I/O module for the protected card communicates the data with the network interface associated with the protected card to protect the device from the failure of the protected card.

Protection bus and method for a telecommunications device

A telecommunications device includes a local area network with redundant first and second buses. Multiple cards coupled to the first and second buses communicate using the first bus. A first monitor coupled to the first and second buses detects a failure of the first bus and communicates a message indicating the failure using a data network. A second monitor also coupled to the first and second buses may detect the failure of the first bus and may also communicate a message indicating the failure using the data network. The first monitor and the second monitor may receive the messages from one another and cause the cards to communicate using the second bus. In a more particular embodiment, the second monitor transmits a test signal using the first bus in response to the message from the first monitor.

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Hollis, NH, United States of America

Brent K Parrish