Abstract: A network system for a data center is described in which an access node sprays a data flow of packets over a logical tunnel to another access node. In one example, a method comprises establishing, by a plurality of access nodes, a logical tunnel over a plurality of data paths across a switch fabric between a source access node and a destination access node included within the plurality of access nodes, wherein the source access node is coupled to a source network device; and spraying, by the source access node, a data flow of packets over the logical tunnel to the destination access node, wherein the source access node receives the data flow of packets from the source network device, and wherein spraying the data flow of packets includes directing each of the packets within the data flow to a least loaded data path.

Abstract: Various embodiments of systems and methods for faster restart of task nodes using periodic checkpointing for data sources are described. A task node obtains data from data sources in order to perform one or more tasks. The task node checkpoints data source progress points for each of its data sources, whether active or inactive, into a common checkpoint data structure at least once every time interval. Multiple task nodes checkpoint their data source progress points into the same common checkpoint data structure. After restart, the task node determines where to resume obtaining data from its data sources by determining a limited portion of the common checkpoint data structure based on the time interval, analyzing only the limited portion of the common checkpoint data structure, retrieving the data source progress points for each of its data sources, and resuming obtaining data from the data sources to perform tasks.

Abstract: A network system for a data center is described in which an access node sprays a data flow of packets over a logical tunnel to another access node. In one example, a method comprises establishing, by a plurality of access nodes, a logical tunnel over a plurality of data paths across a switch fabric between a source access node and a destination access node included within the plurality of access nodes, wherein the source access node is coupled to a source network device; and spraying, by the source access node, a data flow of packets over the logical tunnel to the destination access node, wherein the source access node receives the data flow of packets from the source network device, and wherein spraying the data flow of packets includes directing each of the packets within the data flow to a least loaded data path.

Abstract: A network system for a data center. In one example, a method comprises establishing, by a plurality of access nodes, a logical tunnel over a plurality of data paths across a switch fabric between a source access node and a destination access node included within the plurality of access nodes, wherein the source access node is coupled to a source network device; and spraying, by the source access node, a data flow of packets over the logical tunnel to the destination access node, wherein the source access node receives the data flow of packets from the source network device, and wherein spraying the data flow of packets includes directing each of the packets within the data flow to one of the data paths based on an amount of data previously transmitted on each of the plurality of data paths.

Abstract: Techniques for detecting path failures and reducing packet loss as a result of such failures are described for use within a data center or other environment. For example, a source and/or destination access node may create and/or maintain information about health and/or connectivity for a plurality of ports or paths between the source and destination device and core switches. The source access node may spray packets over a number of paths between the source access node and the destination access node. The source access node may use the information about connectivity for the paths between the source or destination access nodes and the core switches to limit the paths over which packets are sprayed. The source access node may spray packets over paths between the source access node and the destination access node that are identified as healthy, while avoiding paths that have been identified as failed.

Abstract: Systems, methods, and non-transitory computer-readable storage media for stage upgrades in a network. The system generates graph-data structured based representations of devices in the network, wherein respective attributes of the representations is selected based on respective services provided by the devices to tenants in the network and identities of respective tenants serviced by the devices. Next, the system generates a graph showing a distribution of the devices in the network according to the representations, wherein the representations are interconnected in the graph based on service roles of associated devices with respect to tenants in the network and other devices associated with the tenants. The system then schedules an upgrade of devices based on the graph, the upgrade being scheduled in stages, each stage including devices selected for upgrade in that stage, wherein the devices for each stage are selected by identifying devices having respective representations assigned to that specific stage.

Abstract: Techniques for detecting path failures and reducing packet loss as a result of such failures are described for use within a data center or other environment. For example, a source and/or destination access node may create and/or maintain information about health and/or connectivity for a plurality of ports or paths between the source and destination device and core switches. The source access node may spray packets over a number of paths between the source access node and the destination access node. The source access node may use the information about connectivity for the paths between the source or destination access nodes and the core switches to limit the paths over which packets are sprayed. The source access node may spray packets over paths between the source access node and the destination access node that are identified as healthy, while avoiding paths that have been identified as failed.

Abstract: A network system for a data center is described in which a switch fabric provides interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers. The access nodes may be arranged within access node groups, and permutation devices may be used within the access node groups to spray packets across the access node groups prior to injection within the switch fabric, thereby increasing the fanout and scalability of the network system.

Abstract: Network access node virtual fabrics configured dynamically over an underlay network are described. A centralized controller, such as a software-defined networking (SDN) controller, of a packet switched network is configured to establish one or more virtual fabrics as overlay networks on top of the physical underlay network of the packet switched network. For example, the SDN controller may define multiple sets of two of more access nodes connected to the packet switched network, and the access nodes of a given one of the sets may use a new data transmission protocol, referred to generally herein as a fabric control protocol (FCP), to dynamically setup tunnels as a virtual fabric over the packet switched network. The FCP tunnels may include all or a subset of the parallel data paths through the packet switched network between the access nodes for a given virtual fabric.

Abstract: A fabric control protocol is described for use within a data center in which a switch fabric provides full mesh interconnectivity such that any of the servers may communicate packet data for a given packet flow to any other of the servers using any of a number of parallel data paths within the data center switch fabric. The fabric control protocol enables spraying of individual packets for a given packet flow across some or all of the multiple parallel data paths in the data center switch fabric and, optionally, reordering of the packets for delivery to the destination. The fabric control protocol may provide end-to-end bandwidth scaling and flow fairness within a single tunnel based on endpoint-controlled requests and grants for flows. In some examples, the fabric control protocol packet structure is carried over an underlying protocol, such as the User Datagram Protocol (UDP).

Abstract: A fabric control protocol is described for use within a data center in which a switch fabric provides full mesh interconnectivity such that any of the servers may communicate packet data for a given packet flow to any other of the servers using any of a number of parallel data paths within the data center switch fabric. The fabric control protocol enables spraying of individual packets for a given packet flow across some or all of the multiple parallel data paths in the data center switch fabric and, optionally, reordering of the packets for delivery to the destination. The fabric control protocol may provide end-to-end bandwidth scaling and flow fairness within a single tunnel based on endpoint-controlled requests and grants for flows. In some examples, the fabric control protocol packet structure is carried over an underlying protocol, such as the User Datagram Protocol (UDP).

Abstract: A fabric control protocol (FCP) and packet forwarding mechanisms are described that maximize utilization of bandwidth within massive, large-scale data centers having multi-stage data center switch fabric topologies, such as topologies that include a third switching layer formed by super spine switches. Automatic generation of data plane forwarding information referred to as FCP path information enumerates, for each data processing unit (DPU), the available FCP paths. The FCP path information may be based on unique combinations of peak points of the switch fabric for a given DPU with FCP colors assigned to network links that are used to multi-home the DPU to the switch fabric.

Abstract: Techniques for detecting path failures and reducing packet loss as a result of such failures are described for use within a data center or other environment. For example, a source and/or destination access node may create and/or maintain information about health and/or connectivity for a plurality of ports or paths between the source and destination device and core switches. The source access node may spray packets over a number of paths between the source access node and the destination access node. The source access node may use the information about connectivity for the paths between the source or destination access nodes and the core switches to limit the paths over which packets are sprayed. The source access node may spray packets over paths between the source access node and the destination access node that are identified as healthy, while avoiding paths that have been identified as failed.

Abstract: Network access node virtual fabrics configured dynamically over an underlay network are described. A centralized controller, such as a software-defined networking (SDN) controller, of a packet switched network is configured to establish one or more virtual fabrics as overlay networks on top of the physical underlay network of the packet switched network. For example, the SDN controller may define multiple sets of two of more access nodes connected to the packet switched network, and the access nodes of a given one of the sets may use a new data transmission protocol, referred to generally herein as a fabric control protocol (FCP), to dynamically setup tunnels as a virtual fabric over the packet switched network. The FCP tunnels may include all or a subset of the parallel data paths through the packet switched network between the access nodes for a given virtual fabric.

Abstract: Techniques for detecting path failures and reducing packet loss as a result of such failures are described for use within a data center or other environment. For example, a source and/or destination access node may create and/or maintain information about health and/or connectivity for a plurality of ports or paths between the source and destination device and core switches. The source access node may spray packets over a number of paths between the source access node and the destination access node. The source access node may use the information about connectivity for the paths between the source or destination access nodes and the core switches to limit the paths over which packets are sprayed. The source access node may spray packets over paths between the source access node and the destination access node that are identified as healthy, while avoiding paths that have been identified as failed.

Abstract: Network access node virtual fabrics configured dynamically over an underlay network are described. A centralized controller, such as a software-defined networking (SDN) controller, of a packet switched network is configured to establish one or more virtual fabrics as overlay networks on top of the physical underlay network of the packet switched network. For example, the SDN controller may define multiple sets of two of more access nodes connected to the packet switched network, and the access nodes of a given one of the sets may use a new data transmission protocol, referred to generally herein as a fabric control protocol (FCP), to dynamically setup tunnels as a virtual fabric over the packet switched network. The FCP tunnels may include all or a subset of the parallel data paths through the packet switched network between the access nodes for a given virtual fabric.

Abstract: Systems, methods, and non-transitory computer-readable storage media for recovering from a partial failure of a virtual port chain (vPC) domain. The first and second vPC peers may be paired to create a vPC having a virtual address. An endpoint host may communicate with a network via the virtual port channel. The system may detect that the first virtual port channel peer is down. During or after the first vPC reboots, the reachability cost for the first vPC with regards to the virtual address can be set to an inflated value. The first vPC peer may also delay its bring up time while it synchronizes its vPC state information with the second vPC peer. The second vPC can continue to advertise the association between the endpoint host and the virtual address. Upon completion of the synchronization, the first vPC peer may bring up the link and restore the reachability cost.

Abstract: A network system for a data center is described in which an access node sprays a data flow of packets over a logical tunnel to another access node. In one example, a method comprises establishing, by a plurality of access nodes, a logical tunnel over a plurality of data paths across a switch fabric between a source access node and a destination access node included within the plurality of access nodes, wherein the source access node is coupled to a source network device; and spraying, by the source access node, a data flow of packets over the logical tunnel to the destination access node, wherein the source access node receives the data flow of packets from the source network device, and wherein spraying the data flow of packets includes directing each of the packets within the data flow to a least loaded data path.

Abstract: Systems, methods, and non-transitory computer-readable storage media for stage upgrades in a network. The system generates graph-data structured based representations of devices in the network, wherein respective attributes of the representations is selected based on respective services provided by the devices to tenants in the network and identities of respective tenants serviced by the devices. Next, the system generates a graph showing a distribution of the devices in the network according to the representations, wherein the representations are interconnected in the graph based on service roles of associated devices with respect to tenants in the network and other devices associated with the tenants. The system then schedules an upgrade of devices based on the graph, the upgrade being scheduled in stages, each stage including devices selected for upgrade in that stage, wherein the devices for each stage are selected by identifying devices having respective representations assigned to that specific stage.

Abstract: A network system for a data center is described in which a switch fabric provides interconnectivity such that any servers may communicate packet data to any other of the servers using any of a number of parallel data paths. Moreover, according to the techniques described herein, edge-positioned access nodes, permutation devices and core switches of the switch fabric may be configured and arranged in a way such that the parallel data paths provide single L2/L3 hop, full mesh interconnections between any pairwise combination of the access nodes, even in massive data centers having tens of thousands of servers. The access nodes may be arranged within access node groups, and permutation devices may be used within the access node groups to spray packets across the access node groups prior to injection within the switch fabric, thereby increasing the fanout and scalability of the network system.