Hewlett-packard Development Company, L.P.

Hewlett Packard Enterprise Development LP

Jonathan Greenlaw

John Alan Wickeraad

Steven Glen Jorgensen

Michael L Ziegler

Paul Edwin O'Connor

Alan R Albrecht

Mark Shillingburg

Shiro Suzuki

Steven Traub

Examples herein relate to crossbar switches and related circuitry. An example crossbar switch includes a plurality of abutted tiles forming a crossbar. The plurality of abutted tiles includes a plurality of edge tiles and at least one middle tile, where each side of each middle tile abuts an edge tile or another middle tile. Each middle tile includes data inputs connected to data outputs, switched data inputs connected to switched data outputs, and pipeline delay registers coupled to data inputs and switched data outputs to allow transmission of a data signal to change directions inside each middle tile. Each edge tile includes a crossbar input, a crossbar output, and a set of inputs, outputs, and pipeline delay registers to allow transmission of data signals from any side of the edge tile to any other side of the edge tile.

Crossbar switch with pipeline delay registers

A system comprises a processor, a reassembly buffer that receives mini-packets, and at least one data structure that comprises bits. The bits indicate the presence or absence of each of the mini-packets in the reassembly buffer and further indicate whether one of the mini-packets is a final mini-packet in a series of the mini-packets. The processor uses the bits to determine whether all mini-packets forming the series are present in the reassembly buffer. As a result of the determination, the processor causes the series to be read from the reassembly buffer.

Reassembly of mini-packets in a buffer

An apparatus and method of protecting against a denial-of-service (DoS) attack are described. The apparatus comprises a classification engine, a meter engine, and a copy engine. The method comprises assigning a received packet to a meter based upon a classification of the network packet, determining that a DoS attack is in progress based upon a meter count, copying at least one packet from the meter to a processor; and suppressing the copying of subsequently received network packets to the processor.

Method of protecting against denial-of-service attacks

One embodiment disclosed relates to a method of mirroring network traffic. A data packet is received by a network device, and an algorithm including randomization is applied to determine whether the data packet is selected to be mirrored. The packet is sent to a destination port, and if the data packet is selected to be mirrored, then the packet is also sent to a mirror port. Another embodiment of the invention relates to a networking device. The networking device includes at least a plurality of ports, a switching/routing engine, and a mirroring engine. The plurality of ports receive and transmit packets therefrom, and the switching/routing engine is coupled to the ports for transferring the packets therebetween. The mirroring engine is configured to apply an algorithm including randomization to select data packets for mirroring. Other embodiments are also disclosed.

Mirroring of a random subset of network traffic

One embodiment disclosed relates to a method of sampling network traffic. A data packet is received by a network device. Information is extracted from fields in the data packet, and a look-up word is created using the extracted information. A content addressable memory is searched for entries matching the look-up word. If a match is found, then a sampling circuit is queried, and a response is received therefrom. The data packet may be sent to a destination port. In addition, if the response from the sampling circuit indicates that the data packet is chosen to be mirrored, then the data packet may be also sent to a mirror port. Other embodiments are also disclosed.

Sampling of network traffic based on CAM lookup

A method of providing redundancy in a ternary content addressable memory (TCAM), the method including detecting a defective entry in building block in a ternary content addressable memory (TCAM), configuring a failover logic to redirect a software query toward a spare building block and away from the building block with the defective entry, and avoiding in using the building block with the defective entry.

TCAM BIST with redundancy

One embodiment relates to a method of generating an N-bit checksum for variable-length data. An N-bit data word of the variable-length data is received by data input circuitry, and an N-bit input checksum generator is used to calculate an updated value of the N-bit checksum for N-bit data words. A plurality of smaller checksum generators and the N-bit input checksum generator are each used to calculate a last value of the N-bit checksum for the last data word of the variable-length data. Control signals are used to controllably select the last value of the N-bit checksum from outputs of said checksum generators. Other embodiments and features are also disclosed.

Checksum generator for variable-length data

In an embodiment of the invention, a method of providing redundancy in a ternary content addressable memory (TCAM) includes: detecting a defective entry in a ternary content addressable memory (TCAM); marking the defective entry so that the defective entry is visible to a software; and avoiding in using the defective entry. For data that normally would have been written into the defective entry, the data is written into an entry that is subsequent to the defective entry. In another embodiment, the redundancy is provided in a CAM instead of a TCAM.

A system and method for performing counting operations for a plurality of components is disclosed. A memory stores a plurality of counts from different components. The memory is coupled to a counter and the plurality of counts are accessible to the adder for adding addends to the plurality of counts. A count engine controls the adding of the addends to the plurality of counts.

Growing community of inventors

Roseville, CA, United States of America

Jonathan Greenlaw