The disclosure has an object to allow local expansion without causing any loop. The disclosure is a system to which two nodes respectively belonging to different ring networks are connected, wherein the two nodes are connected to each other using a predetermined customized port, upon receipt of a predetermined unicast frame, one of the two nodes transmits the frame to another of the two nodes using the customized port, upon receipt of the predetermined unicast frame from the customized port, the other of the two nodes forwards the unicast frame, and upon receipt of a frame different from the predetermined unicast frame from the customized port, the other of the two nodes discards the frame.

A packet forwarding method and a network device are provided, and the method is applied to the network device. The network device includes a first virtual routing and forwarding (VRF) table and a second VRF table. The method includes: the network device receives a first packet. If the first packet carries tunnel attribute information, the network device forwards the first packet based on the first VRF table. The first VRF table includes one or more local routes, and next-hop outbound interfaces of the one or more local routes are all local outbound interfaces. The network device forwards the first packet based on the first VRF table, so that a packet from a tunnel may be forwarded to a local virtual machine for processing and may not be forwarded to another tunnel endpoint device, to avoid a routing loop during packet forwarding.

During operation, a mesh network access point (MAP) may communicate, via multiple mesh paths in a mesh network with the one or more root access points (RAPs), uplink packets or frames to or from at least two electronic devices. Notably, at a given time, the MAP uses a first mesh path in the mesh paths to communicate a first subset of the uplink packets or frames associated with a first electronic device in the two electronic devices and uses a second (different) mesh path in the mesh paths to communicate a second subset of the uplink packets or frames associated with a second electronic device in the two electronic devices. Moreover, the MAP may dynamically distribute the first electronic device or the second electronic device over the multiple mesh paths, e.g., based at least in part on one or more communication-performance metrics of the mesh paths and/or the mesh network.

A method including receiving, by a first device from a second device in a mesh network, a first status message indicating that the second device is operating in the mesh network as an entry device with respect to the first device or that the first device is operating in the mesh network as an exit device with respect to the second device such that data communicated by the second device outside the mesh network is routed via the first device; and selecting, by the first device based at least in part on the first status message, a third device in the mesh network as an exit device with respect to the first device such that data communicated by the first device outside the mesh network is routed via the third device, the third device being different from the second device. Various other aspects are contemplated.

A method including receiving, by a first device from a second device in a mesh network, a first status message indicating that the second device is operating in the mesh network as an entry device with respect to the first device or that the first device is operating in the mesh network as an exit device with respect to the second device such that data communicated by the second device outside the mesh network is routed via the first device; and selecting, by the first device based at least in part on the first status message, a third device in the mesh network as an exit device with respect to the first device such that data communicated by the first device outside the mesh network is routed via the third device, the third device being different from the second device. Various other aspects are contemplated.

Systems and methods for supporting dual-port virtual router in a high performance computing environment. In accordance with an embodiment, a dual port router abstraction can provide a simple way for enabling subnet-to-subnet router functionality to be defined based on a switch hardware implementation. A virtual dual-port router can logically be connected outside a corresponding switch port. This virtual dual-port router can provide an InfiniBand specification compliant view to a standard management entity, such as a Subnet Manager. In accordance with an embodiment, a dual-ported router model implies that different subnets can be connected in a way where each subnet fully controls the forwarding of packets as well as address mappings in the ingress path to the subnet.

Disclosed herein are system, method, and computer program product aspects for multiple instance Intermediate System to Intermediate System (IS-IS or ISIS) for a multi-area fabric. A network area in a multi-area fabric includes one or more network nodes and a boundary node shared with an other network area of the multi-area fabric outside of the network area. The boundary node can include a first ISIS instance associated with the network area and a second ISIS instance associated with the other network area. The second ISIS instance can be configured to pass information associated with the other network area to the first ISIS instance.

A loop prevention system includes a plurality of networking devices that are coupled together to form a Layer Two (L2) domain and at least a portion of the plurality of networking devices are coupled together in a physical loop configuration. A networking device included in the plurality of networking devices may include at least one L2 domain connection that couples the networking device to at least one of the plurality of networking devices in the L2 domain, and an edge connection that connects the networking device to a computing device that is outside of the L2 domain. The networking device may receive a data frame via the edge connection. The networking device then generates a loop breaker data frame by tagging the data frame with a loop breaker tag and forwards the loop breaker data frame via the at least one L2 domain connection.

A loop prevention system includes a plurality of networking devices that are coupled together to form a Layer Two (L2) domain and at least a portion of the plurality of networking devices are coupled together in a physical loop configuration. A networking device included in the plurality of networking devices may include at least one L2 domain connection that couples the networking device to at least one of the plurality of networking devices in the L2 domain, and an edge connection that connects the networking device to a computing device that is outside of the L2 domain. The networking device may receive a data frame via the edge connection. The networking device then generates a loop breaker data frame by tagging the data frame with a loop breaker tag and forwards the loop breaker data frame via the at least one L2 domain connection.

A parallel flooding topology repair method performed by a node for repairing a flooding topology. The parallel flooding topology repair method detects a failed link and/or a failed node on a flooding topology, determines whether the failed link and/or failed node results in a flooding topology split, and repair the flooding topology by performing a local flooding topology repair process when the flooding topology is split.