Abstract: A method and system for performing network address translations for a session in a network is disclosed. The network includes at least one local network domain, and the at least one local network domain includes at least one computer system. Each computer system has a local address and is associated with a global address. The session exchanges packets that travel between the computer system within the local network domain and another computer system which may be outside of the local network domain. Each packet includes source and destination information. The method and system include determining a direction of travel for each packet, inbound or outbound, by searching a global address table for a match of a key for each packet. The key is provided using a portion of the destination information. The global address table includes at least one entry. Each entry corresponds to the global address for a first corresponding computer system.

Abstract: A structure and technique for preventing collisions using a hash table in conjunction with a CAM to identify and prevent collisions of binary keys. A portion of the hash value of a binary key, which does not collide with a portion of the hash value of any other reference binary key, is used as an entry in the hash table. If two or more binary keys have identical values of the portions of the hash values, each of these binary keys are stored in their entirety, in the CAM. The key in the CAM provides a pointer to a data structure where the action associated with that binary key is stored. If the binary key is not found in the CAM, the binary key is hashed, and a specific entry in the hash table is selected using a portion of this hash value.

Abstract: A method and apparatus useful in network management which makes intelligent, high speed, connection allocation decisions, overcoming difficulties encountered heretofore and providing enhanced network services. During episodes of network congestion, some connection requests for a class of service of low value and with currently a high number of existing connections may be purposefully ignored (not acknowledged with an Acknowledge (ACK) packet) so that the processing capability of a device will not become overwhelmed, causing the dropping of new connection is to note the numbers of connections of different classes relative to their service-level contracts, to ignore abundant, low-value connection requests in accordance with value policies when and only when necessary, and to insure that valuable new connection requests that conform to their contract connection rates can be intelligently accommodated.

Abstract: A control mechanism is established between a network processor and a tree search coprocessor to deal with latencies in accessing the data such as information formatted in a tree structure. A plurality of independent instruction execution threads are queued to enable them to have rapid access to the shared memory. If execution of a thread becomes stalled due to a latency event, full control is granted to the next thread in the queue. The grant of control is temporary when a short latency event occurs or full when a long latency event occurs. Control is returned to the original thread when a short latency event is completed. Each execution thread utilizes an instruction prefetch buffer that collects instructions for idle execution threads when the instruction bandwidth is not fully utilized by an active execution thread. The thread execution control is governed by the collective functioning of a FIFO, an arbiter and a thread control state machine.

Abstract: An ordered semaphore management subsystem and method for use in an application system which includes a plurality of processors competing for shared resources each of which is controlled by a unique semaphore. The subsystem generates an ordered semaphore field (OSF) corresponding to each processor in a linked list of processors and assigns one of four statuses to the OSF depending on the position the processor occupies in the linked list of processors competing for the shared resources. The four states are (1) semaphore head (SH); (2) behind semaphore head (BSH); (3) semaphore head behind (SHB); and (4) skip (Skip). Only the SH processor is allocated the semaphore when requested. A processor not in the SH state will be denied the semaphore even if is available to assure sequential access.

Abstract: A packet network redistributes excess bandwidth for voice and data sessions applying a Quality of Service (QoS) algorithm. The network includes interacting client stations using H.323 protocol managing bit rate according to an algorithm as voice and data sessions are added or removed from the network. The client stations include codecs coupled to the network. The codecs provide voice sessions at a minimum bandwidth using a voice codec bit rate and preferred bandwidth using another voice codec bit rate. A first algorithm applies the QoS algorithm allocating bandwidth between interacting client stations after the addition of a new voice or data session when there is insufficient bandwidth for the new session to receive preferred bandwidth. A second algorithm is applied when a voice or data session is removed from the interacting client stations. If any session is allocated minimum bandwidth the QoS increases a voice session at minimum bandwidth to preferred bandwidth if excess bandwidth is available.

Abstract: A codec detects congestion in a packet network and responds via a session control protocol to re-negotiate codec-type and/or parameters with the receiving codec to reduce bit rate for supporting a session. Once the connection and session are established, encoded packets start flowing between the two codecs. A control entity sends and receives network congestion control packets periodically in the session. The congestion control packets provide a “heartbeat” signal to the receiving codec. When the network is not congested, all “heartbeat” packets will be passed through the network As network congestion increases, routers within the network discard excess packets to prevent network failure. The codecs respond to the missing packets by slowing down the bit rate or proceeding to renegotiate a lower bit rate via the session control protocol. If there are no missing packets, the codecs detect if the session is operating at the highest bit rate, and if not, re-negotiate a higher bit rate.

Abstract: According to the present invention there is provided to a method and system for efficiently routing IP fragments (i.e., datagrams) at layer 3 through layer 7 of the OSI model without reassembling the fragments. Time-consuming reassembly of fragments of a datagram at higher layers that would be required via conventional methods is avoided, thereby improving processing speed of fragments and utilizing fewer resources for processing fragments of a datagram than would be required during reassembly of the fragments via conventional methods.

Abstract: A method and system for performing a pattern match search for a data string having a plurality of characters separated by delimiters. In accordance with the method of the present invention a search key is constructed by generating a full match search increment comprising the binary representation of a data string element, wherein the data string element comprises all characters between a pair of delimiters. The search key is completed by concatenating a pattern search prefix to the full match search increment, wherein the pattern search prefix is a cumulative pattern search result of each previous full match search increment. A full match search is then performed within a lookup table utilizing the search key. In response to finding a matching pattern within the lookup table, the process returns to constructing a next search key. In response to not finding a matching pattern, the previous full match search result is utilized to process the data string.

Abstract: A packet network congestion control system using a biased packet discard policy includes a plurality of end points having codecs operating in a framework, e.g. ITU-T H.323 protocol to establish a communication session. The protocol enables the codecs to negotiate codec type and associated parameters. Once a connection and session are established, compressed voice and data packets start flowing between the two end points. A control entity supplies congestion control packets periodically. The control packets provide a “heartbeat” signal to the codec at the other end of the session. Each codec receiver uses the “heartbeat” signal as an indication of network congestion. As network congestion increases, routers within the network discard excess packets to prevent network failure. The network discards all packets classified as congestion control packets whenever a flow control mechanism detects congestion or a trend toward congestion.

Abstract: A method, system and computer program product for eliminating memory corruption when performing multi-threaded tree operations. A network processor may receive a command to perform a tree operation on a tree on one or more of multiple threads. Upon performing the requested tree operation, the network processor may lock one or more resources during a portion of the execution of the requested tree operation using one or more semaphores. A semaphore may refer to a flag used to indicate whether to “lock” or make available the resource associated with the semaphore. Locking may refer to preventing the resource from being available to other threads. Hence, by locking one or more resources during a portion of the tree operation, memory corruption may be eliminated in a multiple thread system while preventing these resources from being used by other threads for a minimal amount of time.

Abstract: A method and system for improving the performance of a cache. The cache may include a tag entry that identifies the previously requested address by the processor whose data was not located in the cache. If the processor requests that address a second time, then there is a significant probability that the address will be accessed again. When the processor requests the address identified by the tag entry a second time, the cache is updated by inserting the data located at that address and evicting the data located in the least recently used entry. In this manner, data will not be evicted from the cache unless there is a significant probability that the data placed in the cache will likely be accessed again. Hence, data may not be evicted in the cache by the processor and replaced with data that will not be reused, such as in an interrupt routine.

Abstract: Receivers, methods, and computer program products can be used to demodulate a data signal transmitted from a digital source, which has a network sampling rate that is synchronized with a network clock. In an illustrative embodiment, a receiver includes a two-stage interpolator that receives digital samples of the data signal as an input and produces an interpolated digital sample stream to be filtered by an adaptive fractionally spaced decision feedback equalizer. The digital samples received in the interpolator are synchronized with a local clock; however, the interpolated sample stream is synchronized with the network clock. A slicer generates symbols for the samples output from the decision feedback equalizer by comparing the samples with a reference signaling alphabet. The receiver can be used in a V.90 client modem to demodulate pulse code modulated (PCM) data transmitted as pulse amplitude modulated (PAM) signals from a digital network.

Abstract: A method and structure for performing a delayed counter increment is provided. The method and structure allows a counter decision to be modified based upon what the computer system hardware does with the data packet. Subsequent to the generation of a counter command, the processing of the data packet may change: for example, the data packet may be discarded instead of forwarded. Accordingly, the counter increment instruction is changed. A delayed counter increment will perform the actual counter update after the processing of the data packet is completed. In one embodiment of the invention, the counter update action is modified depending upon whether the data packet is forwarded or discarded, and a different counter is selected to be updated. This solves a problem that sometimes the forwarding code is unable to determine if some independent action may later discard a data packet.

Abstract: A low power DSL modem transmitter, suitable for incorporation in integrated DSLAM server line cards, transmits full power physical frames which include a control channel and a data field when data is available for transmission and physical frames having only a control channel or a control channel and a low power synchronization field when data is not available for transmission. And a method for controlling the total power dissipated in the integrated DSLAM by selectively restricting the flow of data packets to the DSLs.

Abstract: A shared digital subscriber line modem achieves reduced total power consumption and data security by generating and transmitting a physical data frame which includes a control channel and a data field to only the connected client modem associated with the intended recipient. A second physical frame which does not include the data field is generated and transmitted to all of the other connected client modems. This method results in a reduction in the power required and provides improved data security by preventing data access to non-addressed client modems.

Abstract: A method and system for determining whether to enforce a plurality of filter rules for a packet including a key in a computer network is disclosed. Each of the plurality of filter rules has a priority. The method and system include accumulating statistics for each of the plurality of filter rules. The statistics indicate a frequency of enforcement for each of the plurality of filter rules. The method and system also include placing the plurality of filter rules in an order for testing against the key. The order is based on the frequency of each filter rule of the portion of the plurality of filter rules. Consequently, more frequently enforced filter rules may be tested first.

Abstract: Packetized voice, video, and data traffic (data frames) are received in a communication traffic sorter. The data frames have a dispatch priority corresponding to their transmission characteristics (flow) and a quality of service parameters. The communication traffic sorter analyzes information in data packets within each data frame and determines an optimum flow for the data frames. A data frame is assigned to a selected queue based on an analysis of the information in its data packets. A data frame may also be assigned to a queue based on a prior analysis of a data frame with like transmission characteristics. Results of analysis are stored and indexed to facilitate processing of subsequent data frames. The network access sorter has circuits to un-pack and re-pack the data frame, when called for, to allow user transmitted data to be processed to create a modified data frame.

Abstract: A mechanism controls a multi-thread processor so that when a fist thread encounters a latency event to a first predefined time interval temporary control is transferred to an alternate execution thread for duration of the first predefined time interval and then back to the original thread. The mechanism grants full control to the alternate execution thread when a latency event for a second predefined time interval is encountered. The first predefined time interval is termed short latency event whereas the second time interval is termed long latency event.

Abstract: A method and system for finding a longest prefix match for a key in a computer network is disclosed. The method and system include providing a main engine and providing an auxiliary engine. The main engine is for storing a first plurality of addresses and for searching the first plurality of addresses for the longest prefix match for the key. None of the first plurality of addresses is a prefix for another address of the first plurality of addresses. The auxiliary engine is for storing and searching a second plurality of addresses. A first address of the second plurality of addresses is capable of including the prefix for a second address of the first plurality of addresses or for a third address for the second plurality of addresses. None of the first plurality of addresses is the prefix for any of the second plurality of addresses. Each of the second plurality of addresses is distinct from each of the first plurality of addresses.