Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1996-12-30
2001-05-15
Felber, Joseph L. (Department: 2732)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S423000, C370S426000
Reexamination Certificate
active
06233246
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of networking devices, and more particularly to a network switch including a switch manager for gathering statistics information in a memory in response to a request by the processor and then informing the processor that the statistics are available, where the processor has ready access to the memory for retrieving the information.
DESCRIPTION OF THE RELATED ART
There are many different types of networks and network systems for sharing files and resources or for otherwise enabling communication between two or more computers. Networks may be categorized based on various features and functions, such as message capacity, range over which the nodes are distributed, node or computer types, node relationships, topology or logical and/or physical layout, architecture or structure based on cable type and data packet format, access possibilities, etc. For example, the range of a network refers to the distance over which the nodes are distributed, such as local-area networks (LANs) within an office or floor of a building, wide-area networks (WANs) spanning across a college campus, or a city or a state, global-area networks (GANs) spanning across national boundaries, etc.
The structure of a network generally refers to the cabling or media and media access used as well as the packet structure of the data transmitted across the media. Various structures are common, including Ethernet using coaxial, twisted pair or fiber-optic cables for operation at 10 megabits per second (Mbps) (e.g. 10Base-T, 10Base-F) or fast Ethernet operating at 100 Mbps (e.g. 100Base-T, 100Base-FX). ARCnet (Attached Resource Computer Network) is a relatively inexpensive network structures using coaxial, twisted pair or fiber-optic cables for operation at 2.5 Mbps. Token Ring topologies use special IBM cable or fiber-optic cable for operation between 1-16 Mbps. Of course, many other types of networks are known and available.
Each network generally includes two or more computers, often referred to as nodes or stations, which are coupled together through selected media and various other network devices for relaying, transmitting, repeating, translating, filtering, etc., the data between the nodes. The term “network device” generally refers to the computers and their network interface cards (NICs) as well as various other devices on the network, such as repeaters, bridges, switches, routers, brouters, to name a few examples. A network operating according to a given communications protocol may be expanded by using one or more repeaters, bridges or switches. A repeater is a hardware device that functions at the physical layer and re-transmits each received packet to every other port. A bridge operates at the data link layer of OSI Reference Model and increases efficiency by filtering packets to reduce the amount of unnecessary packet propagation on each network segment.
A network switch is similar in function to, yet more efficient than, a multiport bridge, which includes a plurality of ports for coupling to several similar networks for directing network traffic among the networks. A network switch usually includes a switching matrix coupled to the ports across a bus and memory for temporarily storing network data, such as Ethernet packets or the like. The switch may also include a processor for performing management functions, such as monitoring statistics, configuration and status information associated with data flow through the network ports. For example, the statistics information may include the number of Ethernet packets handled or dropped. The information may also include the number of “runts”, “overruns”, “jabbers”, late collisions, FCS errors, etc. Configuration data may include status and setup parameters associated with the ports, the switch matrix, memory devices, etc.
The processor was usually coupled to the network ports through the primary data path between the ports and the switch matrix. In this manner, the processor added significant overhead to the data bus when requesting statistical or configuration data. Such overhead traffic reduced the available bus bandwidth for handling network traffic, which is the primary function of a switch. The information was gathered by the ports themselves and then provided to the processor upon request. However, the network ports were usually busy handling network data, so that the processor was forced to wait for significant periods of time before finally receiving the information. This resulted in an inefficient use of the processor and the primary data bus.
It is desired to provide a network switch for gathering statistical information in a more efficient manner without substantially effecting network data flow through the switch and without forcing the processor into a significant number of wait states.
SUMMARY OF THE INVENTION
A network switch according to the present invention includes a plurality of network ports for receiving and transmitting data, where each port includes at least one statistics register for storing statistics information. The information is preferably Ethernet statistical and configuration information. The network switch also includes a switch manager, which further includes a memory, retrieval logic for detecting a statistics request signal and for respondingly retrieving the statistics information for storage in the memory, and response logic for asserting a statistics response signal after the statistics information is stored in the memory. The switch also includes a processor coupled to the switch manager through a bus, where the processor asserts the statistics request signal and then detects assertion of the statistics response signal. Upon detecting the response signal, the processor retrieves the statistics information from the memory. In this manner, the processor is removed from direct connection to the statistics registers and free to complete other tasks while the information is being gathered by the switch manager, thereby increasing the efficiency of the processor and of the network switch. The network switch is useful for facilitating communication in a network system including a plurality of networks coupled to the switch ports, where each network includes one or more network devices.
The switch manager preferably includes a statistics request register, which further includes a statistics request bit for providing the statistics request signal when set, where the processor writes to the statistics request register to set the statistics request bit. One method for effectuating assertion of the statistics request signal is to detect writing to the statistics request register, which may include one or more programmable parameters for specifying the particular statistics information to retrieve. For example, the statistics request register may include a programmable port number, register number and a count of the number of registers to read. The retrieval logic retrieves the statistics information from all of the registers of a port, from one register specified by the register number, or from a number of registers equal to the count beginning with the register identified by the register number. In this manner, the processor writes once to the statistics request register to initiate the request and to specify the particular information to retrieve. The statistics request register is preferably within the memory of the switch manager.
Once the information is stored within the switch manager, there are several ways to inform the processor. The switch manager preferably includes at least one status register including a ready bit indicative of whether the statistics query request is completed. For example, an interrupt register includes a statistics ready bit, which when set, causes an interrupt to the processor across the processor bus. The processor receives the interrupt and respondingly reads the interrupt register to determine the source of the interrupt. Alternatively, a polling register includes a statistics ready bit, where the processor periodically polls the pol
Hareski Patricia E.
Kotzur Gary B.
Mayer Dale J.
Walker William J.
Witkowski Michael L.
Akin Gump Strauss Hauer & Feld & LLP
Compaq Computer Corporation
Felber Joseph L.
LandOfFree
Network switch with statistics read accesses does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Network switch with statistics read accesses, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Network switch with statistics read accesses will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2526960