Abstract: 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.

Abstract: 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—that is, they are not dedicated—they may be re-programmed for normal device operation.

Abstract: The present invention reduces the cost of a minimally configured network device by providing a network device with a distributed switch fabric. Such a network device locates a portion of the switch fabric functionality on each forwarding card allowing the minimal network device configuration to include less than the entire switch fabric functionality. The cost of the minimal configuration is, therefore, reduced allowing network service providers to more quickly recover the initial cost of the network device. As new services are requested, additional functionality, including both forwarding cards and universal port cards may be added to the network device to handle the new requests, and the fees for the new services may be applied to the cost of the additional functionality. Consequently, the cost of the network device more closely tracks the service fees received by network providers.

Abstract: The present invention provides a high switching capacity network device in one telco rack including both physical layer switch/router subsystems and an upper layer switch/router subsystem. Instead of providing a single physical layer switch/router subsystem, multiple physical layer switch/router subsystems are provided. Segmenting the physical layer switch/router into multiple, for example, four, subsystems better utilizes routing resources by allowing etches for the physical layer subsystems to be moved away from the center of the mid-plane/back-plane of the network device. Moving the physical layer subsystem etches away from the center of the mid-plane enables the network device to include an upper layer/switch router subsystem with etches toward the center of the mid-plane.

Abstract: 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.

Abstract: 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+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+1 redundancy for all universal port cards and/or ports but only 1:N redundancy for each N group of forwarding cards.

Abstract: An apparatus for interconnecting a plurality of segments each of which operates in accordance with a bus protocol specifying collision detection and propagation operations. The apparatus includes a switching mechanism including a backplane having P signal paths and P switch ports each with an input and an output. The input of each switch port is connected to a different one of the P signal paths and at each switch port it connects a selectable one or more of the P signal paths to the output for that switch port. The apparatus also includes a plurality of port circuits each connected to a different one of the ports of the switching mechanism.