Abstract: A system and method of protocol and frame classification in a system for data processing is disclosed, including, analyzing a portion of the, packet or frame according to predetermined tests, and storing characteristics of the packet for use in subsequent processing of the frame. The characteristics are preferably obtained with hardware, which does so quickly and in a uniform time period. The stored characteristics of the packet are then used by the network processing complexes in further processing of the frame. The processor is preconditioned with a starting instruction address or cede entry point and the location of the beginning of the layer 3 header as well as flags for the type of frame.

Abstract: In an ordered semaphore management system a pending state allows threads not competing for a locked semaphore to bypass one or more threads waiting for the same locked semaphore. The number of pending levels determines the number of consecutive threads vying for the same locked semaphore which can be bypassed. When more than one level is provided the pending levels are prioritized in the queued order.

Abstract: The decision within a packet processing device to transmit a newly arriving packet into a queue to await further processing or to discard the same packet is made by a flow control method and system. The flow control is updated with a constant period determined by storage and flow rate limits. The update includes comparing current queue occupancy to a threshold. The outcome of the update is adjustment up or down of the transmit probability value. The value is stored for the subsequent period of flow control and packets arriving during that period are subject to a transmit or discard decision that uses that value.

Abstract: A method and system for transmitting packets in a packet switching network. Packets received by a packet processor may be prioritized based on the urgency to process them. Packets that are urgent to be processed may be referred to as real-time packets. Packets that are not urgent to be processed may be referred to as non-real-time packets. Real-time packets have a higher priority to be processed than non-real-time packets. A real-time packet may either be discarded or transmitted into a real-time queue based upon its value priority, the minimum and maximum rates for that value priority and the current real-time queue congestion conditions. A non-real-time packet may either be discarded or transmitted into a non-real-time queue based upon its value priority, the minimum and maximum rates for that value priority and the current real-time and non-real-time queue congestion conditions.

Abstract: Novel data structures, methods and apparatus for finding the longest prefix match search when searching tables with variable length patterns or prefixes. To find the exact match or the best matching prefix, patterns have to be compared a bit at a time until the exact or first match is found. This requires “n” number of comparisons or memory accesses to identify the closest matching pattern. The trees are built in such a way that the matching result is guaranteed to be a best match, whether it is an exact match or a longest prefix match. Using the trail of all the birds and associated prefix lengths enables determination of the correct prefix result from the trail. By construction, the search tree provides the best matching prefix at or after the first compare during walking of the trail or tree.

Abstract: In an ordered semaphore management system a pending state allows threads not competing for a locked semaphore to bypass one or more threads waiting for the same locked semaphore. The number of pending levels determines the number of consecutive threads vying for the same locked semaphore which can be bypassed. When more than one level is provided the pending levels are prioritized in the queued order.

Abstract: A design structure is provided for a slotted ring network, in which a node may transmit a non-renewable slot reservation with any unreserved slot. The reservation restricts other nodes from transmitting a new packet in the slot. When the slot returns around the ring to the reserving node, the slot will be available. Preferably, reservation is made responsive to a starvation condition in the reserving node, which may be detected in any of various ways. In an optional enhancement, a reservation identifies the reserving node, and another node on the ring is free to transmit a new packet in the reserved slot if the new packet will reach its destination at or before the reserving node, and thus will not interfere with the reservation.

Abstract: A method and system for transmitting packets in a packet switching network. Packets received by a packet processor may be prioritized based on the urgency to process them. Packets that are urgent to be processed may be referred to as real-time packets. Packets that are not urgent to be processed may be referred to as non-real-time packets. Real-time packets have a higher priority to be processed than non-real-time packets. A real-time packet may either be discarded or transmitted into a real-time queue based upon its value priority, the minimum and maximum rates for that value priority and the current real-time queue congestion conditions. A non-real-time packet may either be discarded or transmitted into a non-real-time queue based upon its value priority, the minimum and maximum rates for that value priority and the current real-time and non-real-time queue congestion conditions.

Abstract: Novel data structures, methods and apparatus for finding the longest prefix match search when searching tables with variable length patterns or prefixes. To find the exact match or the best matching prefix, patterns have to be compared a bit at a time until the exact or first: match is found. This requires “n” number of comparisons or memory accesses to identify the closest matching pattern. The trees are built in such a way that the matching result is guaranteed to be a best match, whether it is an exact match or a longest prefix match. Using the trail of all the birds and associated prefix lengths enables determination of the correct prefix result from the trail. By construction, the search tree provides the best matching prefix at or after the first compare during walking of the trail or tree.

Abstract: A method, apparatus and computer program product are provided for implementing a pointer and stake model for frame alteration code in a network processor. A current pointer and a stake are provided for a packet selected for transmit. The current pointer is maintained for tracking a current position for frame alteration operations in the packet. The stake is maintained for tracking a start of a current header for frame alteration operations in the packet. The current pointer is used by frame alteration code instructions to specify a sequence of operations relative to the current pointer. The specified frame alteration sequence is compact in terms of code size to operate on data within a small window of bytes. Advance pointer instructions allow the current and stake pointers to be advanced an arbitrary number of bytes into the packet.

Abstract: A system and method of moving information units from a network processor toward a data transmission network in a prioritized sequence which accommodates several different levels of service. The present invention includes a method and system for scheduling the egress of processed information units (or frames) from a network processing unit according to stored priorities associated with the various sources of the information units. A system for allowing peak bursts based on a system of credits and charges is taught along limits on such peak bursts. Also taught is a system for preventing a flow's disconnection and reconnection to the queues from allowing it to unfairly achieve an improved position.

Abstract: In a slotted ring network, a node may transmit a non-renewable slot reservation with any unreserved slot. The reservation restricts other nodes from transmitting a new packet in the slot. When the slot returns around the ring to the reserving node, the slot will be available. Preferably, reservation is made responsive to a starvation condition in the reserving node, which may be detected in any of various ways. In an optional enhancement, a reservation identifies the reserving node, and another node on the ring is free to transmit a new packet in the reserved slot if the new packet will reach its destination at or before the reserving node, and thus will not interfere with the reservation.

Abstract: A method and system for messaging between processors and co-processors connected through a bus. The method permits a multi-thread system processor to request the services of a processor or co-processor located on the bus. Message control blocks are stored in a memory which identify the physical address of the target processor, as well as a memory location in the memory dedicated to the thread requesting the service. When the system processor requests service of a processor or co-processor, a DCR command is created pointing to the message control block. A message is built from information contained in the message control block or transferred to the processor or co-processor. The return address for the processor or co-processor message is concatenated with the thread number, so that the processor or co-processor can create a return message specifically identifying memory space dedicated to the requesting thread for storage of the response message.

Abstract: 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.

Abstract: The decision within a packet processing device to transmit a newly arriving packet into a queue to await processing or to discard the same packet is made by a flow control method and system. The flow control is updated with a constant period determined by storage and flow rate limits. The update includes comparing current queue occupancy to thresholds and also comparing present queue occupancy to previous queue occupancy. The outcome of the update is a new transmit probability value. The value is stored for the subsequent period of flow control and packets arriving during that period are subject to a transmit or discard decision that uses that value.

Abstract: A method and system for identifying a data structure associated with a packet of data. A processor internal to a packet processor may extract one or more fields in a packet header field of a received packet of data to generate a search key. The internal processor may then be configured to select which table, e.g., routing table, quality of service table, filter table, needs to be accessed using the search key in order to process the received packet of data. A determination may then be made by the internal processor as to whether a CAM or a hash table and a Patricia Tree are used to identify the data structure associated with the received packet of data. Based on table definitions in a register, the internal processor may make such a determination.

Abstract: 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. The data structure that is used to store the hash key and the related information in the tree is called a leaf. Each leaf corresponds to a single key that matches exactly with the input key. The leaf contains the key as well as additional information.

Abstract: A system and method of altering frames being processed by a network processing unit. The system includes a set of defined alterations, with some of the alterations being fixed alterations which are advantageously handled by hardware to accomplish the fixed alterations rapidly and without executing a stored program and other alterations which include a variable portion, with these variable alterations being accomplished through the use of stored programs allowing the variables to be used to effect variable alterations to a frame. The present system accommodates a change in the duration of life of a frame or information unit and addition or deletion of bits and also allows for a new cyclic redundancy checking to be accomplished for a revised information unit. Advantageously, the frame alteration system is on the same substrate as the processors.

Abstract: A Resource Reservation System includes a Token Generation Unit (TGU) which generates and circulates among nodes of a communications system a Slotted Token (SLT) message having sub-fields to carry identification number for each input port in a node and the resource available for each input port. On receiving the message the Resource Control Unit (RCU) in each node can write port identification number, available resource in appropriate sub-fields of the SLT message, and reserve resources in other nodes by adjusting information in the sub-field associated with the other nodes.

Abstract: A system and method of moving information units from an output flow control toward a data transmission network in a prioritized sequence which accommodates several different levels of service. The present invention includes a method and system for scheduling the egress of processed information units (or frames) from a network processing unit according to service based on a weighted fair queue where position in the queue is adjusted after each service based on a weight factor and the length of frame, a process which provides a method for and system of interaction between different calendar types is used to provide minimum bandwidth, best effort bandwidth, weighted fair queuing service, best effort peak bandwidth, and maximum burst size specifications. The present invention permits different combinations of service that can be used to create different QoS specifications.