Digital Equipment Corporation

Cabletron Systems, Inc.

Other

Enterasys Networks, Inc.

Digital Equipment Corp., Patent Law Group

Henry S Yang

William R Hawe

Barry A Spinney

Kadangode K Ramakrishnan

Jerry D Hutchison

K K Ramakrishnan

Anthony G Lauck

Rajendra K Jain

G Paul Koning

William C Mallard, Jr

Jerry Hutchison

Richard W Graham

Simoni Ben-Michael

Michael Ben-Nun

Anil G Rijhsinghani

Siman-Tov Ben-Michael

Philip P Lozowick

Moshe De-Leon

Luc A Pariseau

Paul W Ciarfella

Aviad Wertheimer

Shirish S Sathaye

Michael W Carrafiello

Christian Rodgers

Gady Daniely

Wen-Yi Huang

Donald L Post

Mark F Kempf

An electronic nutrition journal that can include one or more portable units capable of reading barcodes and serving sizes on consumed food items either on menus or on items purchased. Portable units can communicate with either an intermediate computer or directly with a server computer that contains a master nutritional database relating nutritional data with bar codes. This master nutritional database can be updated by either user input such as user preferred menus or by visiting websites that contain this data. An external barcode generator can be operated to produce barcodes for commercial operations that sell food such as restaurants, food trucks, vending machines or others so that barcodes can be established for their menus or selections. The intermediate computer or the server can track food intake and provide computations of nutritional values, bench marks, etc. a particular user or for many users. The server and master nutritional database, as well as coding of restaurant menus, etc., can be run as a service that a user could subscribe to.

Electronic nutrition journal

A switch for use in a communications system having multiple local area networks interconnected by multiple switches so as to be configurable into different types of virtual local area networks includes first and second communication ports. The first communication port is connected directly to a local area network and the second communication port interconnects with other system switches. A switch control detects a communication from the local area network and identifies a virtual local area network over which the communication is to be transmitted based upon rules of precedence for different types of virtual local area networks. The communication is appended with a VLAN tag representing the identified virtual local area network so as to form a VLAN communication that is directed to the second communication port for transmission over the identified virtual local area network.

Virtual local area networks having rules of precedence

A switchable interface for conveniently coupling a network station of the CSMA/CD type to a network having any of a variety of communication media. The invention provides a single interface connector through which connection may be made directly to a twisted-pair medium, using the 10BASE-T protocol, or to a medium of a different type, through an AUI protocol and an appropriate media attachment unit. The interface connector has pin assignments chosen to minimize adverse effects of misconfiguring the station by connecting to a network having a protocol that is different from the one selected in the switchable interface. In one form of the invention, the switchable interface has the ability to determine the protocol being used by the network to which it is connected, and to switch the interface accordingly. Use of the common interface reduces station equipment cost and provides for increased user convenience, since only a single connector is needed to connect to a variety of media types.

Common interface for a network having different communication media

The problems of meeting tight latency requirement while keeping network design low in cost and complexity are solved by the present invention of a network controller with a transaction logic block and a descriptor memory. The invention allows the data buffers and the buffer descriptors to be located in two physically separate memory subsystems. Data buffers can reside in a main system memory which are shared by other system clients. The buffer descriptors, which typically require significantly less memory space than data buffers, can reside in a special dedicated memory which can be low cost. The invention provides a method to allow buffer descriptors to be located in a low latency memory, which can be local to the network adapter. The data buffers can be located in a system shared memory. This design allows system shared resources, e.g. main system memory or bus, to be designed with relatively longer delay budget. This provides a significant system benefit since the buffer memory size is typically many orders of magnitude larger than the buffer descriptor memory size. The invention also provides a method where a system bus supports a priority service where low latency is guaranteed. In this embodiment, the data buffers and the descriptors can reside in a shared memory. The network controller uses the priority service when accessing the buffer descriptors.

System for transmitting data packet from buffer by reading buffer

A technique for modifying the IEEE 802.3 standard for selecting backoff times in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, in the event that a collision is sensed by a node that has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for less aggressive, i.e. longer, backoff times before at least the first retransmission attempt made by a node that has captured the channel. Three specific examples of the technique are disclosed. Even though the invention represents a departure from the standard CSMA/CD backoff algorithm, the overall average backoff times provided by the invention can be selected to be consistent with the average times provided by the standard. Moreover, nodes using the invention interoperate successfully with nodes that do not.

Method and apparatus for use in a network of the ethernet type, to

The invention improves the efficiency of buffer descriptor processing by performing descriptor prefetches, where multiple descriptors are read within the same descriptor bus transaction. The invention reads multiple buffer descriptors each time the bus is accessed. This allows for a smaller FIFO in a cut-through network adapter because it reduces the number of bus transactions needed to transfer data.

Buffer descriptor prefetch in network and I/O design

A network adapter for interfacing between a communication network and a host computer operating as a network device, and a method of operation of these components. The adapter is initially conditioned to transmit at a lower of two possible speeds, such as 10 Mbps instead of 100 Mbps, and then senses at which speed the network is operating, before matching to this sensed speed, either the higher speed or the lower speed. If the sensed speed is the lower speed, the adapter transmits a burst of high-speed signals and senses again for high-speed operation. If the network has not switched to high-speed operation, the adapter is conditioned for low-speed operation. After the adapter is conditioned for low-speed or high-speed operation, the network speed is continually sensed and, if the network is not operating at the selected speed for some preselected period of time, the adapter is returned to its initial low-speed state to begin network speed sensing over again.

Automatic network speed adapter

An arbiter of an I/O controller implements an arbitration process for controlling bi-directional data flow between a local area network and a main memory connected to a system bus having variable latency. A receive state machine of the controller manages inbound data bursts from the network by temporarily storing the data in a receive buffer before transfer to the main memory. Outbound data bursts from the main memory are managed by a transmit state machine of the controller, and are temporarily stored in a transmit buffer prior to transmission onto the network. The arbitration process assigns each of the receive and transmit state machines priority for accessing the system bus depending upon certain status conditions of the controller. These conditions include: (i) whether one or both of the state machines are contending for access to the system bus; (ii) whether the controller is configured for full-duplex or half-duplex communication over the network; (iii) the current status of the transmit and receive network ports; and (iv) the current state of the receive and transmit buffers.

Method for assigning priority to receive and transmit requests in

In accordance with principles of the invention, a frame removal mechanism for token ring networks is disclosed. The disclosed system uses strip delimiter frames. The system transmits one or more information frames onto a computer network. The system further transmits one or more strip delimiter frames onto the computer network after the information frame transmission. The system detects strip delimiter frames on the computer network, and strips information frames received from the computer network after the information frame transmission is begun and until one of the strip delimiter frames is detected.

Frame removal mechanism for token ring networks

A technique for modifying the IEEE 802.3 standard for selecting transmit-to-transmit interpacket gap (IPG) intervals in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, to provide fairness and good channel utilization in the event that a node has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for use of a longer interpacket gap (IPG) interval to be used by a node that has been initially unsuccessful in contention for the channel, thereby ensuring that the other node may continue to transmit back-to-back data packets without interruption or collision. After a preselected time interval, the nodes reverse their roles by selecting the opposite IPG intervals. The initial receiver now selects the shorter IPG interval and captures the channel for the preselected time interval.

Frame processing apparatus, and a related method for its operation, for use in a station connected to a token ring network, to ensure rapid stripping of frames from the network without reference to source addresses in the frames, and in spite of the possible presence of extraneous no-owner frames on the network. The adverse effects of extraneous no-owner frames are avoided by any of three techniques. First, transmitted information frames are preceded by a start strip delimiter frame and followed by an end strip delimiter frame. The process strips all incoming frames (except tokens and ring initialization frames, which are specially handled), but does not count the stripped frames until the start strip delimiter frame is detected. Therefore, extraneous frames preceding the transmitted information frames will be stripped but not counted, and all of the transmitted frames will be stripped. In another approach, an estimated stripping time is used to terminate stripping. Frame counters are not then needed and extraneous frames will be stripped prior to the desired information frames. A third approach is to preset the transmitted frame count to some selected value, so that more frames will be stripped than were transmitted. Thus, preceding extraneous frames will be stripped, but the end strip delimiter will still terminate stripping and preclude overstripping.

Frame removal mechanism for token ring networks using one or more start

A system for stripping frames transmitted by a station on a token ring network is disclosed. During operation of the system, the station receives a grant of permission to transmit onto the network. In an example embodiment, the grant of permission is a token. After receipt of the grant of permission to transmit, the station transmits one or more information frames onto the network. Upon transmission of the information frames, the station stops forwarding frames received from the network, thus removing received frames from the network. Removing received frames from the network is referred to as `stripping`. Following transmission of the information frames, the station transmits an end strip delimiter frame onto the network. Upon receipt of the end strip delimiter frame, the station terminates stripping. In an example embodiment, the system is used in a bridge station, the bridge station connecting a first network with a second network.

Frame removal mechanism using end delimiter frames for token ring

A technique for modifying the IEEE 802.3 standard for selecting backoff times in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, in the event that a collision is sensed by a node that has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for less aggressive, i.e. longer, backoff times before at least the first retransmission attempt made by a node that has captured the channel, and in addition provides for the use of a stopped backoff algorithm. Three specific examples of methods to choose a backoff time and two methods of using a stopped backoff algorithm are disclosed. Even though the invention represents a departure from the standard CSMA/CD backoff algorithm, the overall average backoff times provided by the invention can be selected to be consistent with the average times provided by the standard. Moreover, nodes using the invention interoperate successfully with nodes that do not use the invention.

A technique for modifying the IEEE 802.3 standard for selecting transmit-to-transmit interpacket gap (IPG) intervals in a Carrier Sense Multiple Access with Collision Detection (CSMA/CD) network, in the event that a node has captured the network communication channel. If there is a small number of active nodes on the network, one node may capture the channel and the standard backoff algorithm makes it increasingly unlikely for another node to transmit. The new technique provides for less aggressive, i.e. longer, interpacket gap (IPG) intervals to be used by a node that has captured the channel, thereby increasing the likelihood that another node will gain access.

A technique for establishing and maintaining full duplex communication between two stations connected to a token ring network, without physically reconfiguring the station connections or otherwise disturbing the network. Each station continually performs a two node test to ascertain whether there are only two active stations on the network, and updates a two node flag that indicates whether or only two active stations are present. The two node test uses both upstream neighbor and downstream neighbor addresses to update the two node flag, and requires validation of either one of these addresses if the other one of them appears to have changed since the previous observation. A concurrently running full duplex control process uses the two node flag and other conditions to decide whether to initiate or continue transition to full duplex mode. The control process uses an exchange of full duplex request and acknowledgment frames and completes the transition to full duplex mode when each station has transmitted and received a Restricted Token.

Growing community of inventors

Andover, MA, United States of America

Henry S Yang