Abstract: A method of completing a kernel work concurrently with non-kernel work in a computer device having a single-threaded kernel is disclosed. The computer device completes kernel work within the context of a pacer process, which is a user process. In particular, atomic portions of the kernel work are executed in the context of the pacer process at which point nothing else is allowed to run. When an atomic portion of the kernel work has been executed, the pacer process temporarily relinquishes the processor of the computer device, thus suspending the execution of the kernel work and allowing execution of non-kernel work. Interrupts are also handled when execution of the kernel work is suspended. Once the kernel work has been completed, the pacer process goes into a “sleep” mode to await the invocation of another kernel work.

Abstract: Protection switching between primary and secondary paths in a packet-based network involves table entries that are pre-programmed with a primary path, a secondary path, and a value that identifies the primary path, referred to as a primary path identifier (PPI). When table entries are accessed to make forwarding decisions, the PPI is compared to a field that identifies that a particular path is down, referred to as a down path identifier (DPI). If the two fields match, (i.e., PPI=DPI), then the secondary path is selected instead of the primary path as the path on which the traffic should be forwarded.

Abstract: A concept of “Interface Class” is introduced. All logical interfaces that belong to an Interface Class are indistinguishable in hardware. Each Interface Class is associated with one or more packet forwarding rules, such as Access Control Lists (ACLs), Policy Routes, and Quality of Service (QoS). Each Interface Class is also assigned with a Class ID, which is a user-defined integer. When defined in terms of a Class ID, a logical interface (e.g., an L3 Interface) will inherit all the packet forwarding rules associated with the Class ID. In one embodiment, Class IDs and Interface IDs can be stored in the same hardware lookup table in association with data representative of their respective packet forwarding rules.

Abstract: Distributing forwarding information in a router that has a distributed processing architecture involves distributing the forwarding information from one instance of an operating system to another instance of an operating system in parallel using two different communications channels where one of the communications channels is characteristically reliable yet relatively slow and where the other one of the communications channels is characteristically unreliable yet relatively fast. The forwarding information that is distributed via the relatively fast communications channel can be used to rapidly update forwarding tables such as hardware forwarding tables while the forwarding information that is distributed via the reliable communications channel can be used to resolve errors that may occur during distribution via the relatively fast communications channel.

Abstract: A network node maintains an inactive config file of unsuccessfully executed configuration commands. The network node maintains an active config file of active executed configuration commands. In response to a change of conditions that invalidates an active configuration command, the network node moves data from the active config file to the inactive config file. In response to a change of conditions, the network node re-executes inactive commands and moves data from the inactive config file to the active config file if an inactive configuration command is successfully re-executed.