Network congestion management using aggressive timers

#The present invention generally relates to communication in network systems and more particularly to network system congestion management.

#A traditional network system, such as a computer system, has an implicit ability to communicate between its own local processors and from the local processors to its own I/O adapters and the devices attached to its I/O adapters. Traditionally, processors communicate with other processors, memory, and other devices via processor-memory buses. I/O adapters communicate via buses attached to processor-memory buses. The processors and I/O adapters on a first computer system are typically not directly accessible to other processors and I/O adapters located on a second computer system.

#In conventional distributed computer systems, distributed processes, which are on different nodes in the distributed computer system, typically employ transport services to communicate. A source process on a first node communicates messages to a destination process on a second node via a transport service. A message is herein defined to be an application-defined unit of data exchange, which is a primitive unit of communication between cooperating sequential processes. Messages are typically packetized into frames for communication on an underlying communication services/fabrics. A frame is herein defined to be one unit of data encapsulated by a physical network protocol header and/or trailer.

#FIG. 1 is a diagram of a distributed computer system.

#FIG. 2 is a diagram of an example host processor node for the computer system of FIG. 1.

#FIG. 3 is a diagram of a portion of a distributed computer system employing a reliable connection service to communicate between distributed processes.

#In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

#One aspect of the present invention is directed to a method and apparatus providing an aggressive timer-based congestion manager. This aspect facilitates the application of various criteria for selective treatment of frames based on frame or network system attributes as part of congestion detection, reporting, and/or response mechanisms. In one embodiment, the congestion manager supports the enforcement of policies set by network fabric management. In one embodiment, the congestion manager is employed on a network entity, including a network fabric element or end station, such as a switch, router, or endnode.

#An example embodiment of a distributed computer system is illustrated generally at 30 in FIG. 1. Distributed computer system 30 is provided merely for illustrative purposes, and the embodiments of the present invention described below can be implemented on network systems of numerous other types and configurations. For example, network systems implementing the present invention can range from a small server with one processor and a few input/output (I/O) adapters to massively parallel supercomputer systems with hundreds or thousands of processors and thousands of I/O adapters.