摘要:
A system for converting data in one clock domain to a second clock domain comprises a multiplexer which has a select control which is synchronous with a first frequency and is coupled to two bistable registers of which a first is clock controlled in accordance with the first frequency and a second is clock controlled by the second frequency. The data output of the first register is looped back to the second data input of the multiplexer. The select signal operates to couple a data input to the first register whereupon the multiplexer then serves to couple the data output of the first register back to the data input thereof. The arrangement ensures availability of data at the first clock frequency beyond a transition of the second clock frequency. Thus data, preferably multi-bit address data, can be transferred from one clock domain to another with less delay than in customary systems.
摘要:
A network switch includes a look-up engine for obtaining associated data in response to a header portion of a packet and an interlinked network processor such as a RISC for performing a processing function on the header portion or the associated data. Both look-up engine and the network processor may modify a destination port bitmask. The network processor may implement additional packet header processing required for replication or server load balancing.
摘要:
A direct data placement implementation for a data reassembly process. Data within a protocol data unit is placed directly in preassigned application buffers. The network interface card has buffer space into which message headers, segment headers and indicators of escaped data and size of escaped data are placed. A single buffer can contain this information for a complete PDU (or message) and is handed over to enable the next process to run on a per message basis.
摘要:
A network switch includes a look-up engine for obtaining associated data in response to a header portion of a packet and an interlinked network processor such as a RISC for performing a processing function on the header portion or the associated data. Both look-up engine and the network processor may modify a destination port bitmask. The network processor may implement additional packet header processing required for replication or server load balancing.
摘要:
A method of operating a network device in a communication system for the transmission of data packets which include network addresses identifying sources and destinations of data, the network device being capable of both bridging and routing decisions and including a forwarding database by means of which a packet including network address data can be forwarded to at least one port and thereby to at least one network path identified by a network address, and packets can be forwarded to at least one port in response to a media access control address. The method comprises establishing a data table which contains entries comprising a network address of an end station to which a packet is destined, a respective media access control address and an identification of at least one port to which the packet will be directed within the device. The table is accessed in response to network addresses and media access control addresses, whereby the same table can be used for both routing and bridging decisions.
摘要:
An improved "lump" process for producing alpha gypsum, calcium sulfate hemihydrate, from natural gypsum rock of the type wherein lumps of gypsum rock particles (a minimum of about 1/2 inch or 1.3 cm. in size) are calcined to low water-demand alpha hemihydrate by autoclaving in a saturated steam atmosphere, quickly dried and pulverized is disclosed. The improvement allows the thorough processing of natural gypsum as large sized particles or containing considerable selenite and includes the steps of initiating calcination without crystal habit modifier and, after hemihydrate formation has commenced, adding crystal habit modifier and completing calcination under increased steam pressure.
摘要:
An apparatus including logic to receive a data packet comprising a string of characters, said apparatus having a plurality of states and at least one state for every character position in the string of characters; logic to examine the string of characters for matches with a plurality of predefined values, beginning with an initial character; and logic to execute forward exit transitions from any of the plurality of states based upon the examination of the characters, wherein a current state of the apparatus represents a count of a number of characters from the initial character of the string of characters.
摘要:
A deterministic finite state machine organised for the detection of positionally significant matches of characters in a string of characters examines each character in turn to determine a exit transition for a current state of the machine to another state The machine responds to an examination of the string of characters by executing in response to a first character at the commencement of the string a transition from an initial state to another state. The machine has at least one state for every character position, includes a exit transition from each state for each character to another state; and possesses only forward exit transitions each from any of the states whereby the current state of the machine unambiguously represents a count of the number of characters from the commencement of the string. The machine may include at least one match state which indicates that all character matches in the string required by at least one respective rule have been detected. Some but not all the states in the multiplicity of states each have a single exit transition for any value of a respective character in the string. At least some of the states in the multiplicity of states each define an exit transition to a state indicating ‘no match’. The machine may be disposed to cease its examination of the character string on attaining a ‘no match’state.
摘要:
A large FIFO memory device has its total available memory capacity partitioned into memory sections. The partitions are in the form of programmable delimiters in order to determine flexibly the size of the memory sections.
摘要:
A method of transmitting over virtual channels in an asynchronous transfer mode data received in the form of data packets which are assembled in addressable buffers. A single distribution and recovery queue is maintained in conjunction with a start distribution pointer, a finish distribution pointer and a recovery pointer which is initially set to the same place as the finish distribution pointer, free buffers being entered in the queue between the start and finish distribution pointers.