Abstract: The invention provides a method and system for routing information lookup for packets using a routing protocol such as IP. Routing information which has been determined responsive to the packet header, which includes a destination address, a source address, and an input interface for the packet. Routing lookup is performed in response to at least one set of selected routing information, using a lookup table which includes tags both for the routing information and for a bitmask length (thus indicating the generality or scope of the routing information for the routing lookup). The lookup table is structured so that addresses having the most common bitmask length are addressed first, but that more specific addresses are still considered when they are present. It has been discovered that most internet addresses can be found by reference to 24-bit or 21-bit IP addresses, after which 16-bit, 12-bit, and finally 32-bit IP addresses are considered.

Abstract: The present invention is provided with a pipeline for performing in a conveyor-belt style, the processing of obtaining the necessary information for performing an operation after judging the operation to be performed, of the Swap, the Push, and the Pop, and obtaining the output channel information, based on the content of the shim header of the MPLS packet and the information set in advance. The header controller sequentially supplies a top shim header of each packet received from a plurality of lines to the pipeline and performs an actual operation on the top shim header of each packet, based on the obtained information. As the result of the pop operation, when there exists a shim header that becomes a top newly, it repeats the above processing starting from a stage of supplying the shim header of the new top to the pipeline again. Namely, the pop processing of the MPLS packet is not collectively performed at once but performed by looping the pipeline.

Abstract: A general purpose, software-controlled central processor (CP) can be augmented by a set of task specific, specialized peripheral processors (PPs). The central processor accomplishes its functions with the support of the PPs. Peripheral processors may include but are not limited to a packet parser, a packet deconstructor, a search engine, and a packet editor. At each step in the use of this network processor system, the central processor has an opportunity to intervene and modify the handling of the packet based on its interpretation of PP results. The programmable nature of the CP and the PPs provides the system with flexibility and adaptability.

Abstract: An L bit for notifying another router of whether a self-router belongs to a connection-oriented network is newly provided in the options field of a conventional OSPF packet and the OSPF packet, including L bit is transmitted to another router. In this way, each router belonging a network can automatically recognize a router belonging to a connection-oriented network by detecting L bit. Then, by generating a routing tree, a connection-oriented network device can be identified in the routing tree and mapping between a connection-oriented network and a connectionless network can be performed in an edge device.

Abstract: One aspect is directed to a method and apparatus for transferring information, through a shared storage system, between first and second processes running on first and second computers, respectively. Both computers are coupled to a data storage system, with the first computer being coupled through multiple paths. In accordance with one aspect of the invention, at least one of the multiple paths is selected through which to transfer the information between the first process and the data storage system, so that communication between the first process and the shared storage system is not constrained to any particular path. Another aspect is directed to a method and apparatus for processing an out of band control command executed by a host computer in a multi-path system and targeting a device.

Abstract: A method for forwarding data packets to one of a plurality of servers comprising receiving a data packet from a source, at a data packet forwarding device having a plurality of ports, performing a hashing function using a unique component of the data packet as a seed value for the hash, generating a hash value using the hashing function, looking up a table for an address of one of the plurality of servers using the hashed value as an index to the table, and forwarding the data packet to a server corresponding to the address.

Abstract: A method of broadcasting a packet to the ports belonging to one VLAN of a network, whereas the network has multiple network switches. Each network switch has its own local ports and a local VLAN table. Each local VLAN table stores local port membership of its network switch, and switch membership per VLAN identifier. The local VLAN table is accessed by a VLAN identifier which is stored in the packet, and retrieves the local port membership and switch membership associated with the VLAN identifier. A copy of the packet is provided to each local port and to each switch retrieved from said local VLAN table.

Abstract: An apparatus for compressing the header of ATM cells in order to provide greater bandwidth includes means for discriminating cells/packets (1310), means for detecting header (1320), means for compressing header (1330), means for combining compressed header with payload (1350), means for discriminating compressed header cell/packet (1710), means for detecting header in compressed header and separating header from payload (1720), means for decompressing header (1730), and means for combining decompressed header with payload (1740) to form cell/packets.

Abstract: A network switch, configured for performing layer 2 and layer 3 switching in an Ethernet (IEEE 802.3) network without blocking of incoming data packets, includes network switch ports, each including a flow module configured for generating a packet signature based on layer 3 information within a received data packet. The flow module generates first and second hash keys according to a prescribed hashing function upon obtaining first and second portions of layer 3 information. The flow module combines the first and second hash keys to form the packet signature, and searches an on-chip signature table that indexes addresses of layer 3 switching entries by entry signatures, where the entry signatures are generated using the same prescribed hashing function on the first and second layer 3 portions of the layer 3 switching entries.

Abstract: Lookup scheme in which a tuple representing a plurality of flow properties is parsed into multiple subtuples for application in recursive lookups. A first subtuple including a first subset of bits from the tuple is applied to the flow information database and returns a result including a nickname having a smaller bit count than the first subtuple. A second subtuple including a second subset of bits from the tuple and the nickname are combined and applied to the flow information database. The lookups continue until a result indicates that no recursion is required. The final lookup result includes flow information applicable to one or more of modifying, enqueuing or forwarding the packet. A truncated lookup capability enables common processing across a group of distinct flows having common flow properties.

Abstract: A network switch, configured for performing layer 2 and layer 3 switching in an Ethernet (IEEE 802.3) network without blocking of incoming data packets, includes network switch ports, each including a packet classifier module configured for generating a packet signature based on information within a received data packet and hash action values specified within a user-programmable template. In particular, the network switch stores a plurality of user-programmable templates, each configured for identifying a corresponding class of data packet. Each user-programmable template includes hash action values specifying initiation and termination of a hash function based on a byte offset of a received data packet.

Abstract: VPI/VCI of an ATM cell is translated into an internal ID by distributing VPI/VCI entries into sections in a table according to a portion of each VPI/VCI entry. A section to be searched according to the portion of a VPI/VCI of the received ATM cell is selected; and a search over the selected section is performed to find an entry corresponding to the VPI/VCI of the received ATM cell. An internal ID corresponding to the found entry is outputted.

Abstract: A network handler uses a DMA device to assign packets to network processors in accordance with a mapping function which classifies packets based on its content, e.g., bits in one or more header fields. Preferably, the mapping function is implemented as a hash function, which uses a predetermined number of bits from packet as inputs. The result of this function specifies the processor to which the packet is assigned. To make implementation manageable in a high-traffic environment, each processor may be equipped with a queue, which holds pointer information. Such a pointer provides an indication of the area in memory where incoming packet resides. The network handler is particularly useful in a Fiber Channel environment, where the hash function may be implemented to assign all packets from the same sequence to the same processor, thereby resulting in improved processing efficiency.

Abstract: A packed radix data system is described, the packed radix data system including packed nodes which include a base pointer and an existence field, the existence field having a number of bits which indicate the existence or non-existence of a possible child node. By counting the number of bits to the left of an indexed bit in the existence field, an offset value is determined. The offset value is combined with the base pointer value to determine the child node address.

Abstract: A lookup unit matrix combines a plurality of lookup units to provide a longest prefix match for a search key longer than the lookup unit's mapper key. A portion of the search key is provided to each of the plurality of lookup units in a single search request issued to the lookup unit matrix. Each lookup unit in the lookup unit matrix performs a multi-level search for the result value based on the portion of the search key forwarded as the mapper key and the result of a multilevel search in the previous lookup unit. The search results in a value corresponding to the search key stored in a single location in one of the lookup units.

Abstract: An apparatus and method for efficient hashing uses both an identifying portion of a data packet, e.g., source and destination ID, and an identifying value of the node, e.g., the IP address of the node, to generate a hash result. By inserting a unique value into the hash operation at each node, the invention effectively provides for a different hash implementation at each node. As a result, in situations where multiple paths or multiple links within a path are available to forward packets, traffic can be split over the multiple paths and links. Inefficient utilization of network links found in prior systems which use the same hash operation at each node are eliminated.

Abstract: In a computer network of devices, at least some of the devices (i.e. the DCHP devices) have a static (e.g. MAC) address which does not change over time and a dynamic (e.g. IP) address which may change over time. There is disclosed a method and computer program for mapping the static address and dynamic address for the devices comprising polling said devices using said IP addresses and during said polling determining the MAC addresses of the devices, and providing a set of mapped static and dynamic addresses, said method including repeating the steps of the method at intervals. Using the method of the invention, it is possible, when entering a particular conversation in a database, to access the IP addresses, to determine which is the current DHCP device that address maps to, and assign the conversation to that device and store it in the database assigned to that device. Therefore, for each DHCP device, one can store a history of the conversations or traffic involved in that device.

Abstract: An apparatus for transferring data on a network. The apparatus includes a switch comprising a primary component for switching the data through the switch. The apparatus includes a secondary component for switching the data through the switch if the primary component fails. The apparatus includes a mechanism for counting the data that has been received, transmitted or dropped by the switch without including any redundancy in the counting of the data due to the primary component and secondary component both able to switch data through the switch. A method for transferring ATM cells on a network. The method includes the steps of switching the ATM cells with an ATM switch of the ATM network having a primary component for switching the cells and a secondary component for switching the cells if the primary component fails.

Abstract: A system provides predictive routing of packets in a network with multiple nodes. The system receives messages from the nodes (740). The messages contain predictions regarding future events that may happen to entities associated with the nodes. The system extracts the predictions from the received messages (750), determines active states of the entities based on the predictions (750), and generates a routing table using the active states of the entities (760). The system uses the routing table to route packets through the network.

Abstract: A computer network has two or more switches and a plurality of links. A first machine and a second machine are interconnected by the network in such a way that there exist multiple paths through the network from an N_Port of the first machine to an N_Port of the second machine. Network traffic from the N_Port of the first machine to the N_Port of the second machine is distributed between the multiple paths such that frames related to any single exchange traverse the same path yet frames of a first exchange need not traverse the same path as frames of a second exchange. Frames of each exchange therefore tend to be received by their destination in order with respect to other frames of that exchange, while they are not necessarily received in-order with respect to frames of other exchanges.

Abstract: A packet switching apparatus includes a plurality of lower layer processing units, a table, and a processing unit. Each of the plurality of lower layer processing units carries out a process for a data link layer and a physical layer to a packet. The table stores flow data which includes a routing data and a search key. The processing unit searches the flow data from the table based on a search key of a routing packet received via one of the plurality of lower layer processing units, when the flow data for the search key of the routing packet is registered on the table. Also, the processing unit selectively transfers the routing packet to one of the plurality of lower layer processing units based on the routing data of the searched flow data.

Abstract: The present invention provides a per-flow dynamic buffer management scheme for a data communications device. With per-flow dynamic buffer limiting, the header information for each packet is mapped into an entry in a flow table, with a separate flow table provided for each output queue. Each flow table entry maintains a buffer count for the packets currently in the queue for each flow. On each packet enqueuing action, a dynamic buffer limit is computed for the flow and compared against the buffer count already used by the flow to make a mark, drop, or enqueue decision. A packet in a flow is dropped or marked if the buffer count is above the limit. Otherwise, the packet is enqueued and the buffer count incremented by the amount used by the newly-enqueued packet. The scheme operates independently of packet data rate and flow behavior, providing means for rapidly discriminating well-behaved flows from non-well-behaved flows in order to manage buffer allocation accordingly.

Abstract: A system and method for generating a common flow identifier for messages flowing in each direction of a bidirectional message flow are disclosed. A packet classifier may extract header information from a packet and transform at least a subset of the header information into a flow identifier. The transformation may produce the same flow identifier for messages flowing in each direction of a bidirectional message flow. A hash table having entries for each bidirectional message flow may include the flow identifiers. The packet classifier may be used to control communications between an internal network and external resources.

Abstract: A method (50) for determining if it is necessary to perform a search for a specified address in an address lookup table (LUT) (58) containing a plurality of addresses (59) is disclosed. The method (50) provides at least one ordered list (56) of address existence fields. The address existence fields are associated with lookup addresses obtained from at least one portion of the plurality of addresses (59). The method (50) indexes into the at least one ordered list (56) to access at least one address existence field associated with a corresponding portion of the specified address. The method (50) further checks the at least one address existence field to determine if a search of the specified address in the address LUT (58) is necessary.

Abstract: A network switch includes network switch ports, and switching logic for determining the output port for each received layer 2 type data packet. The switching logic includes an address table configured for storing address-based switching decisions, a trunk table configured for assigning each network switch port to a corresponding identified trunk, and a trunk distribution table identifying the network switch ports assigned to each identified trunk. The switching logic determines the output port for each corresponding received layer 2 type data packet based on a corresponding switching decision for the received layer 2 type data packet, and based on selection of an entry in the trunk distribution table based on information within the received layer 2 type data packet. Hence, the network switch is able to perform trunk-based switching with minimal complexity, ensuring switching of data packets at the wire rate.

Abstract: A network switch comprises a multiplicity of ports for receiving and forwarding addressed data packets, a forwarding engine for directing packets received at the ports to at least one other port, a register for storing unit identifications of a set of units including the network unit, and hashing logic for selecting one of the unit identifications in response to address data in a packet. The forwarding engine makes a determination whether the one of the unit identifications corresponds to the network unit and is operative to direct the packet in accordance with that determination. The use of the register enables a substantial increase in the number of ports that can be members of a stack-wide trunk.

Abstract: A packet classifier having a forest of hash tables data structure. The forest of hash tables data structure includes a number of hash tables, each hash table having a bit mask corresponding to an equivalent set of rules. Each hash table includes a number of entries, wherein an entry of a hash table may correspond to a rule. One or more of the hash tables may include a marker in one entry, wherein the marker identifies another one of the hash tables. The hash table identified by the marker is a descendant of the hash table in which the marker is placed.

Abstract: In general, in one aspect, the disclosure describes a method of processing bits of a frame. The method includes accessing a subset of bits of a frame and based, at least in part, on the subset of bits, determining an address of an instruction within a set of instructions that perform at least one framing operation on the bits. The method executes instructions at the determined instruction address.

Abstract: A method and apparatus for performing a lookup in a switching device of a packet switched network where the lookup includes a plurality of distinct operations each of which returns a result that includes a pointer to a next operation in a sequence of operations for the lookup. The method includes determining a first lookup operation to be executed, executing the first lookup operation including returning a result and determining if the result includes a pointer to another lookup operation in the sequence of operations. If the result includes a pointer to another lookup operation, the lookup operation indicated by the result is executed. Else, the lookup is terminated.

Abstract: A method of using routing tables. In this method, routing differs from ordinary table routing in that the part of a destination address (e.g., DestinationID) used for a table lookup is variable. Networks using the full address space of a network node can be made by partitioning the network topology into several levels, such as a top topology and any number of sub-topologies. With a DestinationID of N−1 bits, a routing table of 2n entries is sufficient to support topologies using the full address space, wherein n<N−1.

Abstract: Load balanced transport of best efforts traffic together with delay-bounded traffic over a multilink bundle combines fragmentation and fragment distribution for best efforts packets with per-flow balancing for delay-bounded traffic. In the preferred embodiments, the best efforts packets receive Multilink Protocol treatment, including fragmentation and addition of sequence headers. Fragments of packets for one such communication go over the various links within the bundle, as appropriate for load balancing on the links. For each delay-bounded flow, such as for a VOIP service, the sending node hashes the packet header data and applies all packets for the flow to one of the links, assigned as a function of the hash value. Different flow headers produce different hash results; therefore the node sends different flows over the different links in a substantially balanced manner.

Abstract: A number of hash tables are accessed concurrently with a different computed index for each hash table. Each index identifies a location in one of the hash tables at which a forwarding entry may be stored. To search for a forwarding entry, the locations identified by the indices computed by performing a hash function on a search key are searched to a match for the search key. To insert a forwarding entry if single cycle inserting is not required and all the locations identified by the indices computed by performing a hash function on an insert key are used then the data base is reordered so that the forwarding entry can be inserted at one of the locations identified by one of the computed indices for the insert key. If single cycle insertion is required and all the locations identified by the computed indices are used, one of the locations identified by one of the computed indices for the insert key is randomly overwritten by the forwarding entry.

Abstract: In a computing network environment having a gateway device electronically connected to a plurality of hosts potentially connected to one or more routers and local area networks, a method and apparatus is provided for dynamically configuring, deconfiguring and monitoring all connected hosts. Special IPX commands are provided to add or remove information about hosts in a routing table. The command provides information about the connected hosts' IPX sessions, router information and IPX packets and their final destinations, and connection routes. In another embodiment of the present invention the IPX command is also used to receive information and pass information about new IPX stations in the network environment. By providing a counter and incrementing it each time an IPX packet is received from the network, the most used entries are identified. A second special IPX host command is also provided for deconfiguring and removing entries from the routing table in a manner similar to the one described above.

Abstract: A router allowing the entry hit probability of the cache to be increased is disclosed. The cache is searched using a different mask for each cache entry. A maximum or optimum cache prefix length is determined as a length of upper bits of the destination address of the received packet which are not masked by a corresponding mask. Alternatively, the cache is searched using longest prefix match (LFM). A cache entry allowing a plurality of destination addresses to be hit can be registered in the cache, resulting in increased cache hit probability.

Abstract: An apparatus comprising a first circuit and a second circuit. The first circuit may be configured to generate a plurality of match signals in response to an incoming data signal. Each match signal is generated in response to different search criteria. The second circuit may be configured to present a protocol indication signal in response to the plurality of match signals.

Abstract: Methods and systems for re-routing a connection through an explicitly routed network. The methods involve initially re-routing the connection to a reduced constraint connection through the network; establishing a fully constrained path through the network; subsequently re-routing the connection to the fully constrained connection through the network.

Abstract: Embodiments of the present invention relates to an apparatus and method for routing AAL5 PDU in a mobile communication system, capable of routing AAL5 PDU using a Hash lookup table.

Abstract: A mechanism for path provisioning between an origin node (O) and a destination node (D) over BLSR networks. All ring pairs including O and D are examined and a communications path is calculated for each valid ring sequence. The calculated path is compared with the current best path until an optimal path is found. Significantly improved run-time is obtained using ring sequence reduction (RS-R) and path construction reduction (PC-R) while the quality solution set is maintained. A path provisioning tool calculates the optimal path and a Pareto curve for the BLSR network. The optimal path displays inter-ring connection configurations, the signal flows, and associated data like cost and unavailability. The Pareto curve allows various levels of assured availability to be provided while keeping the cost to a minimum.

Abstract: Systems and methods are described for converting priority based rules into isomorphic longest match rules. Rules for packet processing may be presented to a networking device in priority order, through an interface such as a Command Line Interface (CLI) or from networking applications which may reside on the networking device. The networking device may include hardware and/or software layers for accelerating packet processing; a forwarding layer may include hardware and/or software designed to perform longest match searches on packets. Prioritized rules may be converted into a data structure for the forwarding layer, so that a longest match search performed by the forwarding layer on the data structure is equivalent to a priority order search on the prioritized rules.

Abstract: One embodiment of the present invention provides a system that uses a destination address of a packet to perform a fast lookup to determine a service that is specified by the destination address. The system initially receives a packet at an interface node in the cluster of nodes. This packet includes a source address specifying a location of a client that the packet originated from, and the destination address specifying a service provided by the cluster of nodes. The system uses the destination address to perform a first lookup into a first lookup structure containing identifiers for scalable services. Note that a scalable service is a service that provides more server node capacity for the scalable service as demand for the scalable service increases. If no identifier for a scalable service is returned during the first lookup, the system sends the packet to a server node in the cluster of nodes that provides a non-scalable service.

Abstract: One embodiment of the present invention provides a system for forwarding a packet between nodes in a clustered computing system. The system operates by receiving the packet at an interface node in the clustered computing system. This packet includes a source address specifying a location of a client that the packet originated from, and a destination address specifying a service provided by the clustered computing system. The system selects a server node in the clustered computing system to send the packet to from a plurality of server nodes that are able to provide the service. Next, the system forwards the packet to the server node so that the server node can provide the service to the client by, attaching a transport header to the packet, the transport header containing an address of the server node, and sending the packet to the server node through an interface. This interface is used for communications between the interface node and other nodes in the clustered computing system.

Abstract: A communication system having a multiple access segment (2,48), which comprises a plurality of end systems (6,44) and a switching node (4,46) configured such that each end system can transmit packets to the switching node and such that the switching node can transmit packets which are received by all the end systems. The switching node comprises a switch (5,47) for switching packets from the end systems to intermediate destinations within the system, and the MA segment operates in accordance with a protocol which provides a quality of service requested by the end systems for the packets transmitted over the segment.

Abstract: A system and method for detecting communication requirements in a network and placing nodes in various stages of activity where conditions allow. The system and method provides an algorithm to detect changes in node activity levels and alter operations, such as update transmissions and route selections, based upon changes detected. In particular, the algorithm determines activity level at a node at each routing update interval based on factors such as a number of new destinations the node can reach, a number of route modifications that the node can implement, a number of routes from the node whose lengths have changed and a number of destinations the node can no longer reach. The node can then increase or decrease the rate that it exchanges its routing information with neighboring nodes based on an increase or decrease in this activity level.

Abstract: Disclosed is an apparatus and method for storing and searching computer node addresses in a computer network system. In one embodiment, the apparatus comprises a frame forwarding device such as a switch. The switch includes two MAC address tables including a primary MAC address table and secondary MAC address table both for storing and searching MAC addresses. The primary table stores records that contain compressed values of MAC addresses. The records are contained in storage locations that are referenced using the compressed value of the MAC address as a search index. In order to account for searching collisions that may result from different MAC addresses compressing to the same value, each record in the primary address table is linked to a chain of records in the secondary table. The records in the secondary table store the full value of the MAC address. Each chain of records in the secondary address table contains MAC addresses the present invention.

Abstract: An Ethernet switch using a hash table for address lookup. The hash function is based upon taking a slice of the coefficients of a remainder polynomial obtained after dividing the sum of an address polynomial and a shifted key polynomial by a cyclic redundancy check (CRC) polynomial. The hash table has multiple buckets for each hash table address. The switch may adaptively choose different CRC polynomials for polynomial division or different slices of the remainder polynomials to reduce bucket leakage.

Abstract: A method and apparatus to search for routing information is described. According to an embodiment, a technique is described to search for routing information that uses a first technique on at least a portion of a first section of an address and a second technique on at least a portion of a second section of an address. In one embodiment, a best-match technique, such as a Longest Prefix Match technique, is used on at least a portion of a topology section of an address, and an exact-match technique is used on a portion of an interface ID of the address.

Abstract: A packet interception system intercepts message packets transmitted from a packet source or to a packet destination, and processes them so as to facilitate verification of the contents and the sequence with which the message packets are intercepted, and for storing the processed message packets for later use. The packet interception system generates for each intercepted message packets respective hash values based on the respective intercepted message packet and the hash value generated for the previously-intercepted message packet, or, for the first intercepted message packet, a value that is provided to identify the session. To verify a previously-stored intercepted message packet, the packet interception system, or another device, using the same hash algorithm, can process the sequence of stored intercepted message packets up to and including the intercepted message packet to be verified, to and compare the hash value generated to the previously-generated hash value for each of the message packets.

Abstract: Embodiments of the present invention relate to a method and system for efficiently maintaining a MAC address filtering table. According to the embodiments, a first entry in a linked list of the filtering table may be deleted without delaying or compromising the integrity of a concurrent look-up in the table.

Abstract: One embodiment of the present invention provides a system that uses a packet distribution table to distribute packets to server nodes in a cluster of nodes that operate in concert to provide at least one service. The system operates by receiving a packet at an interface node in the cluster of nodes. This packet includes a source address specifying a location of a client that the packet originated from, and a destination address specifying a service provided by the cluster of nodes (and possibly a protocol). The system uses the destination address to lookup a packet distribution table. The system then performs a function that maps the source address to an entry in the packet distribution table, and retrieves an identifier specifying a server node from the entry in the packet distribution table. Next, the system forwards the packet to the server node specified by the identifier so that the server node can perform a service for the client.

Abstract: The invention provides apparati and methods for processing a packet. The processing is done according to a table and context based scheme.