摘要:
A flow control apparatus implemented in a virtual path ATM communication system comprising a plurality of nodes interconnected by physical links which comprise virtual paths including a plurality of virtual channels. A connection between two nodes is defined as the combination of a physical link, a virtual path, and a virtual channel. Connections are shared between a reserved bandwidth service and a best effort service. ATM data cells conveyed on said best effort service are routed from node to node by analyzing their virtual connection identifier. Queues, allocated as needed from a pool of free queues, are used to store all incoming ATM data cells having the same virtual channel identifier.
摘要:
An error correction apparatus includes an error control circuit which computes for each burst of a message (for a destination unit) an error correction code as a function of an initial error correction code at the first burst of the message or of the error correction code of the previous burst and of the data bytes of the burst. The burst error correction code is sent on a medium which is separate from the data transport medium as a companion of the burst. Also, the error control circuit receives the burst error correction code from an origin unit and generates the burst error correction code to be compared with the received burst error correction code. If a mismatch is detected, the burst found in error is flagged.
摘要:
The CRC for the CPS Header of an ATM AAL2 cell is generated by a CRC generator which uses the 8 bits of the CID field to generate partial 5 bits CRCs which are loaded in a first table. The 6 bits LI field and 5 bits UUI field are added to the partial 5 bits CRC to form 16 bits. The CRC generator uses the 2.sup.16 bits to generate a second CRC table. The CRC for a particular CPS header is generated by correlating bits in the CID field, LI field and UUI field with the two tables.
摘要:
The present invention relates to a device for combining at least two data signals having an input data rate into a single data stream having an output data rate being higher than the input data rate for transmission on a shared medium or vice versa, particularly, to a single SDH/SONET framer capable of handling a large range of SDH/SONET frames from STM-i to STM-j with an aggregated total capacity corresponding to an STM-j frame where i and j are integers in the range from 1 to 64 or higher according to the STM-N definition of the SDH/SONET standards. More over, the present invention can also be extended to work with STS-1 as lowest range. STS-1 exists in SONET only not SDH and corresponds to a data rate of 51.5 Mb/s a third of the 156 Mb/s of STM-1. The device according to the present invention comprises at least two ports for receiving and/or sending said at least two data signals, a port snning unit for extracting data from the data signals received by said ports and/or synthesizing data to be transmitted via the ports, respectively, whereby said port scanning unit is configured to extract data from ports providing data streams having at least two different input data rates and/or to synthesize data to be transmitted via the ports taking data streams having at least two different data rates.
摘要:
A network switch apparatus, components for such an apparatus, and methods of operating such an apparatus in which data flow handling and flexibility is enhanced by the cooperation of a control point and a plurality of interface processors formed on a semiconductor substrate. The control point and interface processors together form a network processor capable of cooperating with other elements including an optional switching fabric device in executing instructions directing the flow of data in a network.
摘要:
A network switch apparatus, components for such an apparatus, and methods of operating such an apparatus in which data flow handling and flexibility is enhanced by the cooperation of a control point and a plurality of interface processors formed on a semiconductor substrate. The control point and interface processors together form a network processor capable of cooperating with other elements including an optional switching fabric device in executing instructions directing the flow of data in a network.
摘要:
Novel data structures, methods and apparatus for finding a full match between a search pattern and a pattern stored in a leaf of the search tree. A key is input, a hash function is performed on the key, a direct table (DT) is accessed, and a tree is walked through pattern search control blocks (PSCBs) until reaching a leaf. The search mechanism uses a set of data structures that can be located in a few registers and regular memory, and then used to build a Patricia tree structure that can be manipulated by a relatively simple hardware macro. Both keys and corresponding information needed for retrieval are stored in the Patricia tree structure. The hash function provides an n->n mapping of the bits of the key to the bits of the hash key.
摘要:
A method and system for creating on a computer a timing based representation of an integrated circuit using a graphical editor operating on the computer. The method includes first in creating timing diagrams identifying the elements of the circuit and their time based interconnections. The method further comprises a translation of the timing based diagram editor files into HDL statement. The preferred embodiment is described, it comprises the use of an ASCII editor and a translation program to VHDL statements. A system is also described implementing the steps of the method in a computer. In order to avoid having different tools to translate timing based diagram editor files into HDL statements, a first step translating graphical editor output file into a PostScript file is performed by executing the “print to file” command of the printing driver of the computer. The PostScript file is then translated into a bitmap file using a RIP. The translation is then performed from the bitmap file into the HDL statements. This translation is “universal” as it can be used for any type of initial graphical file containing the timing diagram.
摘要:
The invention discloses a method and an apparatus for use in high speed networks such as Asynchronous Transfer Mode (ATM) networks providing support for processing multipriority data flows at media speed, the major constraint being to share the storage and the ALU between all the tasks. The invention consists first in grouping the tasks in processes and the processes in set of processes all organized in decreasing order of their priority ; `on the fly`interruption of a lower priority process/set of processes by a higher priority process/set of processes is possible as well as reuse of the shared resources during task void states inactive in a process or between processes.In the preferred embodiment of the invention, the support of the reserved bandwidth and non reserved bandwidth ATM services data flows requires two different groups of processes, the highest priority being for the group of processes serving the reserved bandwidth service.With the principle of the invention when used in network equipment the media speed is sustained and many different network traffics can be simultaneously supported. The apparatus implementing the solution of the invention, allowing sharing of resources saves place and costa by the improved reduced number of sophisticated hardware components such as static memories and programmable logic circuits.
摘要:
The method and apparatus of the present invention solve the problem of scheduling the transmission of cells in packet switched networks having network connections requiring a minimum bandwidth at connection establishment. The method and the apparatus further support any mixed traffic flow including connections requiring a minimum bandwidth, a fixed reserved bandwidth or no bandwidth at connection establishment. Scheduling is controlled by a dual scheduling mechanism having a first scheduler, triggered by absolute time, for scheduling the minimum service connections up to a rate corresponding to their reserved minimum bandwidth, a second scheduler and a queue of minimum service connection identifiers for communication between the two scheduling schemes. With the dual scheduling mechanism of the present invention, the minimum bandwidth for connections reserving a minimum bandwidth at connection establishment is guaranteed in each point of the connection path and at any time, with the level of fairness of the scheduling of the remaining bandwidth depending on the quality of the second scheduler.