Abstract:
A device which switches data processing from an active processor, about to fail, to a back-up processor includes a memory change detector which captures memory changes in the memory of the active processor and a mirroring control circuit which causes the memory changes when committed by establishing recovery point signals generated by the active processor to be dumped into the memory of the back-up processor so that the back-up processor resumes operation of the active processor from the last established recovery point.
Abstract:
The invention relates to a mechanism to be used in an integrated packet/circuit switched telecommunication network. It allows instantaneously on a per slot basis, the re-allocation of unused bandwidth left by a circuit user source to the background packet flow, and allows giving it back to the circuit source as it resumes its activity. The circuit user data Cd are sent through the network during slots of frames which are assigned to the circuit users on a per- call basis. Interfacing means (30, 32) are provided to generate slot qualifying bits Caq which are set to a first value when the corresponding circuit users are active and to a second value when the corresponding cirucit users are inactive. These qualifying bits are transported through the network in correspondence with the slot they qualify and sensed to cause the slots having a Caq set to the second value to be filled with packet bits.
Abstract:
A line scanning device which operates under the control of a microprocessor connected to a control memory in which a memory location area is assigned to each line is provided for a line adapter in a communication controller for receiving or sending message bits in series from or to terminals connected to the lines using any protocols. It comprises a first store which includes a first and a second memories, an area being assigned to each line in each of the memories which can be read and written in the same time and a second store which includes a single memory in which a storage location area is assigned to each line. These stores are addressed by a control and address unit which includes first and second address counters under the control of an elementary time counter, the first counter outputting the address information relating to the first store during time t provided for scanning a line, and the second counter outputting the address information relative to the second store during time nt, n being at least equal to 4, and control circuitry receiving said address information and the elementary time information for providing at the outputs of the control and address unit, memory address and read/write control information at times selected during the scanning period and sequentially, the addresses of the present lines which are scanned.
Abstract:
A method of operating a packet parser in a computing system includes providing a configurable packet pointer by the packet parser, the packet pointer configured to index a configurable number of atomic parsing elements, the atomic parsing elements having a configurable size, in a data stream received by the computing system for extraction, wherein the indexed atomic parsing elements are non-contiguous in the data stream; and receiving the extracted indexed atomic parsing elements from the data stream by the packet parser.
Abstract:
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.
Abstract:
A method and structure are disclosed for dispatching appropriate data to a network processing system comprising an improved technique for extracting protocol header fields for use by the network processor. This technique includes basic classification of a packet according to the types of protocol headers present in the packet. Based on the results of the classification, specific parameter fields are extracted from corresponding headers. All such parameter fields from one or more protocol headers in the packet are concatenated into a compressed dispatch message. Multiples of such dispatch messages are bundled into a single composite dispatch message. Thus, selected header fields from N packets are passed to the network processor in a single composite dispatch message, increasing the network processor's packet forwarding capacity by a factor of N. Likewise, multiple enqueue messages are bundled into a single composite enqueue message to direct enqueue and frame alterations to be taken on the bundle of N packets.
Abstract:
A mechanism for offloading the management of receive queues in a split (e.g. split socket, split iSCSI, split DAFS) stack environment, including efficient queue flow control and TCP/IP retransmission support. An Upper Layer Protocol (ULP) creates receive work queues and completion queues that are utilized by an Internet Protocol Suite Offload Engine (IPSOE) and the ULP to transfer information and carry out send operations. As consumers initiate receive operations, receive work queue entries (RWQEs) are created by the ULP and written to the receive work queue (RWQ). The ISPOE is notified of a new entry to the RWQ and it subsequently reads this entry that contains pointers to the data that is to be received. After the data is received, the IPSOE creates a completion queue entry (CQE) that is written into the completion queue (CQ). After the CQE is written, the ULP subsequently processes the entry and removes it from the CQE, freeing up a space in both the RWQ and CQ. The number of entries available in the RWQ are monitored by the ULP so that it does not overwrite any valid entries. Likewise, the IPSOE monitors the number of entries available in the CQ, so as not overwrite the CQ.
Abstract:
Systems and methods for scheduling data packets in a network processor are disclosed. Embodiments provide a network processor that comprises a best-effort scheduler with a minimal calendar structure for addressing schedule control blocks. In one embodiment, a four-entry calendar structure provides for rate-limited weighted best effort scheduling. Each of a plurality of different flows has associated schedule control blocks. Schedule control blocks are stored as linked lists in a last-in-first-out buffer. Each calendar entry is associated with a different linked list by storing in the calendar entry the address of the first-out schedule control block in the linked list. Each schedule control block has a counter and is assigned a rate limit according to the bandwidth priority of the flow to which the corresponding packet belongs. Each time a schedule control block is accessed from a last-in-first-out buffer storing the linked list, the scheduler generates a scheduling event and the counter of the schedule control block is incremented. When an incremented counter of a schedule control block equals its rate limit, the schedule control block is temporarily removed from further scheduling until a time interval concludes.
Abstract:
A method and system for performing a lookup for a packet in a computer network are disclosed. The packet includes a header. The method and system include providing a parser, providing a lookup engine coupled with the parser, and providing a processor coupled with the lookup engine. The parser is for parsing the packet for the header prior to receipt of the packet being completed. The lookup engine performs a lookup for the header and returns a resultant. In one aspect, the lookup includes performing a local lookup of a cache that includes resultants of previous lookups. The processor processes the resultant.
Abstract:
A system and method for reducing latency in a host Ethernet adapter (HEA) includes the following. First, the HEA receives a packet with an internet protocol (IP) header and data in the HEA. The HEA parses a connection identifier from the IP header and accesses a negative cache in the HEA to determine if the connection identifier is not in a memory external to the HEA. The HEA applies a default treatment to the packet if the connection identifier is not in the memory, thereby reducing latency by decreasing access to the memory.