Equipe Communications Corporation

Ciena Corporation

Nicholas A Langrind

Joseph D Kidder

Daniel J Sullivan, Jr

Barbara A Fox

Brian Branscomb

Chris R Noel

Peter B Everdell

Corey Simons

Peter Pothier

Jonathan D Madsen

Terrence S Pearson

Roland T Provencher

Richard L Whitesel

The present invention provides a method and apparatus for improving transmission of control information within a network device and between multiple connected network devices. Specifically, a control path is included within a network device that is independent of the data path and dedicates control path resources to each distributed processor within the network device. Dedicating resources insures that each processor has sufficient bandwidth on the control plane to transmit control information at high frequencies. This may prevent starvation of data transmissions during periods of high control information transfers and may also reduce the likelihood or further spreading of control information storms when one or more network devices in a network experiences a failure.

Network device including dedicated resources control plane

The present invention provides methods and apparatus for decoupling functional processes, such as network protocol applications and device drivers, from hardware resources through the use of logical resources. Logical resources are created to represent the hardware resources within a computer system and a map is created which associates each logical resource with each hardware resource. Functional processes are associated with the logical resources instead of with the hardware resources such that a functional process may be moved to a different hardware resource simply by changing the map to associate the logical resource associated with the functional process with a different hardware resource.

Decoupling processes from hardware with logical identifiers

Methods are disclosed for establishing a path for data transmissions in a system having a plurality of possible paths by creating a configuration database and establishing internal connection paths based upon a configuration policy and the configuration database. The configuration policy can be based on available system resources and needs at a given time. In one embodiment, one or more tables are initiated in the configuration database to provide connection information to the system. For example, a path table and a service endpoint table can be employed to establishing a partial record in the configuration database whenever a user connects to a particular port on a universal port card in the system. The method can further include periodically polling records in the path table and transmitting data from the partial records to a policy provisioning manager (PPM). The PPM then implements a connection policy by comparing one or more of the new path characteristics, to the available forwarding card resources in the quadrant containing the universal port card port and path. The path characteristics can include the protocol, the desired number of time slots, the desired number of virtual circuits, and any virtual circuit scheduling restrictions. The PPM can also take other factors into consideration, including quality of service, for example, redundancy requirements or dedicated resource requirements, and balancing resource usage (i.e., load balancing) evenly within a quadrant.

Policy based provisioning of network device resources

The present invention provides an upper layer network device with one or more physical layer data test ports. The data supplied to the test ports reflects the data received by the network device with minimal modification and no upper layer translation or processing, and supplying the data to the test ports does not impact or disrupt the service provided by the network device. Only a small portion of the network device need be operable to send data to the test ports. In addition, the test ports are programmable while the network device is operating and without impacting its operation. Moreover, because the test ports are programmable&#x2014;that is, they are not dedicated&#x2014;they may be re-programmed for normal device operation.

Upper layer network device including a physical layer test port

The present invention provides a computer system having a control process and a device driver process that is in communication with the control process, and a local back-up process, independent of both the control process and the device driver process. The local back-up process facilitates recovery of the device driver process. In one aspect of the invention, the computer system is a network device that includes a control plane and a data plan. The control plane includes a control process, and the data plane includes a device driver process. A local back-up process, independent of both the control process and the device driver process, facilitates recovery of the device driver process if the device driver process is terminated.

Maintaining a local backup for data plane processes

A distributed software redundancy design is disclosed to minimize network outages and other problems associated with component/process failures by spreading software backup (in the so-called &ldquo;hot state&rdquo;) across multiple elements. The distributed redundancy architecture of the present invention also permits the location of the hardware backup element to float, that is, if a primary element fails, the functions can be transferred over to the backup element. When the failed primary element is replaced, the replacement hardware can serve as the hardware backup. If one or more of the primary processes on a particular element experiences a software fault, the processor on the line card may terminate and restart the failing process or processes. Once the process or processes are restarted, a copy of the last known dynamic state (i.e., the backup state) can be retrieved a from corresponding backup processes executing on a second line card and initiate an audit process to synchronize retrieved state with the dynamic state of associated other processes.

Distributed process redundancy

The present invention provides a network device, such as a network switch or a router, having a high degree of modularity and reliability. The network device includes a data plane and a control plane. The data plane relays datagrams between a pair of receive and transmit network interface ports. The control plane runs management and control operations, such as routing and policing algorithms which provide the data plane with instructions on how to relay cell/packets/frames. Further, the control plane includes an internal control device that is primarily responsible for managing the internal resources of the network device, and a separate external control device that is primarily responsible for operations relating to the interfacing of the network device with an external environment.

Functional separation of internal and external controls in network devices

The present invention provides a computer system having a modular control process, and a modular device driver process that works in conjunction with the control process. The device driver process is capable of continuing operation even if the control process is terminated, for example, upon detection of a fault. In one aspect, the invention provides a network device that includes a control plane and a data plane. The control plane includes a modular control application for establishing and terminating network connections, and the data plane has an independent, modular device driver process for transmitting data over network connections established by the control application. The device driver process is capable of continuing to transmit data over established network connections even if the control application is terminated.

Independent restoration of control plane and data plane functions

The present invention provides a method and apparatus for supporting multiple redundancy schemes in a single network device. In one network device, various redundancy schemes are supported including 1:1, 1&plus;1, 1:N, no redundancy or a combination of redundancy schemes. In addition, the redundancy scheme or schemes for physical network device cards (i.e., universal port cards) or ports may be different from the redundancy scheme or schemes for forwarding network device cards. For example, a network manager may want to provide 1:1 or 1&plus;1 redundancy for all universal port cards and/or ports but only 1:N redundancy for each N group of forwarding cards. As another example, the network manager may provide certain customers with 1:1 redundancy on both universal port cards (or ports) and forwarding cards to ensure that customer's network availability while providing other customers, with lower availability requirements, with various other redundancy scheme combinations, for example, 1:1, 1&plus;1, 1:N or no redundancy for port cards or ports and 1:N or no redundancy for forwarding cards. The present invention allows customers having different availability/redundancy needs to be serviced by same network device.

Growing community of inventors

Carlisle, MA, United States of America

Nicholas A Langrind