Abstract: Methods, systems, and apparatuses are provided for managing and routing data in a multi-tier network architecture. The methods include transmitting a data flow comprising a sequence of data packets to a source leaf switch and determining if an intended route exists in a forwarding table stored at the source leaf switch using routing metadata. If the intended route does not exist, a control packet is transmitted to a centralized coordinator switch, which modifies an allocation table to include an updated route. The forwarding table at the source leaf switch is then updated with the updated route, and the data flow is transmitted to its destination.

Abstract: There is provided a method and apparatus to provide notification of change events for microburst mitigation. The method is used by a sending device and includes tracking changes in scheduled data to be sent in a traffic flow and identifying a positive change in an amount of scheduled data to be sent in the traffic flow. The sending device then marks one or more packets to be sent in the traffic flow with a notification field, and then transmits the one or more packets including the notification field. The notification field can then be used by a recipient device, for example a network element, to identify and mitigate microbursts in a proactive manner.

Abstract: Methods and systems for partially or fully distributed network verification are described. In partially distributed network verification, each network device generates a respective device-level binary decision diagram (BDD) representing the logical behavior of the respective network device for a network property of interest. The device-level BDDs from each network device are received by a verification service that performs verification by generating an input BDD representing an input header space, and applies each device-level BDD in a logical path from a source device to a destination device, and reports the output BDD. In fully distributed network verification, each network device is responsible for calculating a device-specific output BDD by applying a device-specific BDD, which represents the logical behavior of the network device, to a device-specific input BDD.

Abstract: A method of load balancing in a communications network includes transmitting, by a source node, to a destination node, a first plurality of packets of a “flowlet” of a flow of packets. Each of the first flowlet of packets includes a plurality of header fields and a randomizer. The header fields and the randomizer are used by a networking device located between the source node and the destination node to select an output port of the networking device for the packets of the first flowlet. Further methods include selecting, by the source node, based on a criteria, a second randomizer for inclusion in a plurality of packets of a second flowlet of packets, waiting a time delay after transmitting the first flowlet of packets, then, inserting the second randomizer into the sequential second flowlet of packets, and transmitting the second flowlet of packets.

Abstract: A method of load balancing in a communications network includes transmitting, by a source node, to a destination node, a first plurality of packets of a “flowlet” of a flow of packets. Each of the first flowlet of packets includes a plurality of header fields and a randomizer. The header fields and the randomizer are used by a networking device located between the source node and the destination node to select an output port of the networking device for the packets of the first flowlet. Further methods include selecting, by the source node, based on a criteria, a second randomizer for inclusion in a plurality of packets of a second flowlet of packets, waiting a time delay after transmitting the first flowlet of packets, then, inserting the second randomizer into the sequential second flowlet of packets, and transmitting the second flowlet of packets.

Abstract: There is provided a method and apparatus to provide notification of change events for microburst mitigation. The method is used by a sending device and includes tracking changes in scheduled data to be sent in a traffic flow and identifying a positive change in an amount of scheduled data to be sent in the traffic flow. The sending device then marks one or more packets to be sent in the traffic flow with a notification field, and then transmits the one or more packets including the notification field. The notification field can then be used by a recipient device, for example a network element, to identify and mitigate microbursts in a proactive manner.

Abstract: Methods and systems related to construction and implementation of high radix topologies are disclosed. The nodes of the network topology are divided into a number of groups. Intra-group connections are constructed by connecting the nodes of each group according to a first complementary base graph. Inter-group connections are constructed based on a second complementary base graph and a plurality of permutation matrices. Each permutation matrix represents a pattern for selecting source group and destination group for each inter-group connection. One permutation matrix is randomly assigned to each edge of the second complementary base graph. An inter-group connection is constructed by identifying a source node and a destination node corresponding to a selected edge of the second complementary base graph, and identifying a source group and a destination group according to the permutation matrix assigned to the selected edge.

Abstract: Methods and systems for partially or fully distributed network verification are described. In partially distributed network verification, each network device generates a respective device-level binary decision diagram (BDD) representing the logical behavior of the respective network device for a network property of interest. The device-level BDDs from each network device are received by a verification service that performs verification by generating an input BDD representing an input header space, and applies each device-level BDD in a logical path from a source device to a destination device, and reports the output BDD. In fully distributed network verification, each network device is responsible for calculating a device-specific output BDD by applying a device-specific BDD, which represents the logical behavior of the network device, to a device-specific input BDD.

Abstract: Methods and systems for partially or fully distributed network verification are described. In partially distributed network verification, each network device generates a respective device-level binary decision diagram (BDD) representing the logical behavior of the respective network device for a network property of interest. The device-level BDDs from each network device are received by a verification service that performs verification by generating an input BDD representing an input header space, and applies each device-level BDD in a logical path from a source device to a destination device, and reports the output BDD. In fully distributed network verification, each network device is responsible for calculating a device-specific output BDD by applying a device-specific BDD, which represents the logical behavior of the network device, to a device-specific input BDD.

Abstract: Methods, systems and media for network model checking using entropy based binary decision diagram (BDD) compression are described. Two related compression techniques are described: bit level reduction to reduce the number of bits required for each network field according to its nature, and field level reduction to reduce the size of the BDD tree by finding a near-optimum ordering of the fields in the BDD space. These two techniques, separately or together, may alleviate the state explosion problem the limits application of BDD based model checking. The two techniques complement each other synergistically, particularly in the domain of computer network checking and verification.

Abstract: Methods and systems for network verification are described. An input binary decision diagram (BDD) is defined to represent an input header space to query for a network property of interest. The input BDD is provided as input to a device-level BDD representing a source device in a logical topology representing connections among devices of the network. Each device in the network is represented by a respective device-level BDD in the logical topology. An output BDD is calculated, representing an output header space outputted by a destination device in the logical topology. The output BDD is calculated by sequentially applying, to the input BDD, each device-level BDD in a logical path from the source device to the destination device. The output BDD is then reported, and the reported output BDD is compared with an expected output BDD, to verify the network property of interest.

Abstract: Methods and systems for partially or fully distributed network verification are described. In partially distributed network verification, each network device generates a respective device-level binary decision diagram (BDD) representing the logical behavior of the respective network device for a network property of interest. The device-level BDDs from each network device are received by a verification service that performs verification by generating an input BDD representing an input header space, and applies each device-level BDD in a logical path from a source device to a destination device, and reports the output BDD. In fully distributed network verification, each network device is responsible for calculating a device-specific output BDD by applying a device-specific BDD, which represents the logical behavior of the network device, to a device-specific input BDD.

Abstract: Methods and systems for network verification are described. An input binary decision diagram (BDD) is defined to represent an input header space to query for a network property of interest. The input BDD is provided as input to a device-level BDD representing a source device in a logical topology representing connections among devices of the network. Each device in the network is represented by a respective device-level BDD in the logical topology. An output BDD is calculated, representing an output header space outputted by a destination device in the logical topology. The output BDD is calculated by sequentially applying, to the input BDD, each device-level BDD in a logical path from the source device to the destination device. The output BDD is then reported, and the reported output BDD is compared with an expected output BDD, to verify the network property of interest.

Abstract: Methods, systems and media for network model checking using entropy based binary decision diagram (BDD) compression are described. Two related compression techniques are described: bit level reduction to reduce the number of bits required for each network field according to its nature, and field level reduction to reduce the size of the BDD tree by finding a near-optimum ordering of the fields in the BDD space. These two techniques, separately or together, may alleviate the state explosion problem the limits application of BDD based model checking. The two techniques complement each other synergistically, particularly in the domain of computer network checking and verification.