Abstract: The present apparatus and method of use comprises a system that enables a cell of data to be transmitted one time over a high speed data bus to an switch system where it is then distributed to each of the destinations for which it is intended. A fabric access device and a multiplex devices are each formed to have groups of buffers for buffering signals according to type. The first group of buffers is for temporarily storing data that is to be delivered to only one destination. The second group of buffers is for holding the cells that are to be transmitted to a plurality of devices. In those embodiments in which the unicast and multicast cells are transmitted over the same line or bus a parsing unit examines a field within the header portion of each cell to determine whether the cell is a unicast or multicast cell. If the cell is a unicast cell, it is temporarily stored within the unicast receive buffer set. If the cell is a multicast cell, then it is temporarily stored in the multicast buffer set.

Abstract: A method and apparatus for efficiently performing a longest match search are provided. According to one aspect of the present invention, an entry in a forwarding database, a routing table, or the like is located using an improved longest match search. A mask is applied to an address, such as a destination Internet Protocol (IP) address, to determine a masked address that is to be used for purposes of locating a matching entry in the forwarding database. The forwarding database is searched for an entry that matches the masked address. Subsequent masks are produced by performing an address-sensitive decimation of the former mask. For example, the former mask may be shortened based upon the location of the least significant bit containing a one in the masked address. According to another aspect of the present invention, data forwarding employs the improved longest match search. Data is received at a port. An address is extracted from the data.

Abstract: A switching system includes a switch fabric that includes groups of buffers for each port interface device that communicates with external communication devices through an Ethernet plane. The port interface device is formed to receive congestion ratings reflecting buffer usage within the switch fabric for each device coupled to transmit and receive packets through the switching fabric and to determine whether to route to the switching fabric or drop the packet based upon the congestion rating of the destination device and upon a quality of service rating for the packet.

Abstract: A system enables a cell of data to be transmitted one time over a high speed data bus to an Ethernet switch system where it is then distributed to each of the destinations for which it is intended. A first group of buffers is for temporarily storing data that is to be delivered to only one destination. A second group of buffers is for holding the cells that are to be transmitted to a plurality of devices. In the described embodiment of the invention, the unicast and multicast cells are transmitted over the same line or bus. The invention further includes a switch processor that is formed to detect congestion within the switch fabric and to transmit a congestion rating to each device coupled to transmit and receive data through the switch fabric.

Abstract: A method and apparatus for efficiently switching cells through a switch fabric are provided. According to one aspect of the present invention, logic for forwarding and filtering multicast data is distributed among various layers of a network device, such as a switch, router, bridge, or the like. Data is received at a first port of an input/output (I/O) card. A multicast group identifier corresponding to the data is determined. The data and the multicast group identifier are then transferred to a switching card which indexes into a first set of correlation data with the multicast group identifier to identify a set of egress forwarding paths that lead to I/O cards having members of the multicast group. The switching card forwards the data to the I/O cards via the set of egress forwarding paths identified. For their part, the I/O cards identify a set of ports associated with the multicast group by indexing into a second set of correlation data and forwarding the data to each of the ports identified.

Abstract: A method and apparatus for efficiently performing a longest match search are provided. According to one aspect of the present invention, an entry in a forwarding database, a routing table, or the like is located using an improved longest match search. A mask is applied to an address, such as a destination Internet Protocol (IP) address, to determine a masked address that is to be used for purposes of locating a matching entry in the forwarding database. The forwarding database is searched for an entry that matches the masked address. Subsequent masks are produced by performing an-address-sensitive decimation of the former mask. For example, the former mask may be shortened based upon the location of the least significant bit containing a one in the masked address. According to another aspect of the present invention, data forwarding employs the improved longest match search. Data is received at a port. An address is extracted from the data.

Abstract: A method and apparatus for efficiently searching a forwarding database or similar data structure are provided. According to one aspect of the present invention, the overall average time required to forward a packet from the ingress port of a network device to one or more egress ports may be reduced by attacking the worst case forwarding database search. Data is received at a first port of the network device and a search key is extracted from the data. Typically the search key includes one or more of a source or destination Internet Protocol (IP) address, a souce or destination Media Access Control (MAC) address, and/or a Virtual Local Area Network (VLAN) tag. Ultimately, the data is forwarded to a second port of the network device based upon a matching entry located by the search. The search includes retrieving keys from entries of the forwarding database and comparing the search key to the keys until a matching entry is located.

Abstract: A method and apparatus for increasing the throughput and forwarding rate of a switch fabric are provided. According to one aspect of the present invention, a packet forwarding device includes a plurality of port interface devices (PIDs), memory access circuitry, and a management device. The PIDs are configured to fragment packets into cells. A portion of a cell serves as forwarding information. The memory access circuitry receives cell data from the PIDs to receive cell data. The memory access circuitry includes a data interface that outputs cell data and an independent control interface that outputs forwarding information. A memory is coupled to the data interface of the memory access circuitry to temporarily store the cell data received from the memory access circuitry. A management device is coupled to the independent control interface of the memory access circuitry to receive the forwarding information. The management device employs the forwarding information to organize cells into one or more groups.

Abstract: A method and apparatus for efficiently performing a longest match search are provided. According to one aspect of the present invention, an entry in a forwarding database, a routing table, or the like is located using an improved longest match search. A mask is applied to an address, such as a destination Internet Protocol (IP) address, to determine a masked address that is to be used for purposes of locating a matching entry in the forwarding database. The forwarding database is searched for an entry that matches the masked address. Subsequent masks are produced by performing an address-sensitive decimation of the former mask. For example, the former mask may be shortened based upon the location of the least significant bit containing a one in the masked address. According to another aspect of the present invention, data forwarding employs the improved longest match search. Data is received at a port. An address is extracted from the data.

Abstract: A method and apparatus for efficiently switching cells through a switch fabric are provided. According to one aspect of the present invention, logic for forwarding and filtering multicast data is distributed among various layers of a network device, such as a switch, router, bridge, or the like. Data is received at a first port of an input/output (I/O) card. A multicast group identifier corresponding to the data is determined. The data and the multicast group identifier are then transferred to a switching card which indexes into a first set of correlation data with the multicast group identifier to identify a set of egress forwarding paths that lead to I/O cards having members of the multicast group. The switching card forwards the data to the I/O cards via the set of egress forwarding paths identified. For their part, the I/O cards identify a set of ports associated with the multicast group by indexing into a second set of correlation data and forwarding the data to each of the ports identified.

Abstract: In a communication network, including a first node and a plurality of neighbor nodes that are linked by communication channels to the first node, a data set is retrieved from neighbor nodes according to the following process:1. identifying the data set to be retrieved in the first node;2. identifying neighbor nodes in the plurality that have a copy of the identified data set;3. supplying requests for individual blocks in the data set across the communication channels essentially in parallel to the identified neighbor nodes;4. receiving the individual blocks as the individual blocks are returned from the neighbor nodes; and5. assemblying data set in the first node from the received individual blocks.