Abstract: In one embodiment, a first multiple spanning tree (MST) region configuration for an MST process may be maintained at a switch in a computer network, where the first configuration has a virtual local area network (VLAN)-to-instance (VI) mapping that maps each of one or more VLANs to one of one or more MST instances in the MST region. The switch may subsequently receive a second MST region configuration that has a different VI mapping than the first configuration, and may determine one or more VLANs of the second configuration that have a different VI mapping from the first configuration (“affected VLANs”). Accordingly, in response to a trigger to apply the second configuration at the switch, the affected VLANs are blocked for a delay, and the second configuration may be applied at the switch without restarting the MST process.

Abstract: Embodiments provide a method, network device, and computer program product for optimizing traffic in a link-state network distributed across a plurality of sites. The method, network device, and computer program product include receiving a multi-destination message at a first node within the link-state network. Additionally, the method, network device, and computer program product include identifying a plurality of multi-destination trees within the network, each tree having a respective root node. The method, network device, and computer program product determine a plurality of cost values corresponding to each of the plurality of multi-destination trees, based on one or more links along a shortest path from the first node to the respective root node of each tree. Based on the determined cost values, the method, network device, and computer program product select one or more of the multi-destination trees and transmit the multi-destination message using the selected tree.

Abstract: A system in an operating system of a first network device for using Spanning Tree Protocol to determine a port of a device in a first administrative domain to transmit data between the first network device and a second administrative domain. The system determines each port in a device of the first administrative domain connected to a bridge for transmitting between the first network device and the second administrative domain. A priority of each these ports is determined by priority data. The port having a highest priority is then selected to transmit said data between said first network device and said second administrative domain.

Abstract: In one embodiment, a first multiple spanning tree (MST) region configuration for an MST process may be maintained at a switch in a computer network, where the first configuration has a virtual local area network (VLAN)-to-instance (VI) mapping that maps each of one or more VLANs to one of one or more MST instances in the MST region. The switch may subsequently receive a second MST region configuration that has a different VI mapping than the first configuration, and may determine one or more VLANs of the second configuration that have a different VI mapping from the first configuration (“affected VLANs”). Accordingly, in response to a trigger to apply the second configuration at the switch, the affected VLANs are blocked for a delay, and the second configuration may be applied at the switch without restarting the MST process.

Abstract: In one embodiment, a first multiple spanning tree (MST) region configuration for an MST process may be maintained at a switch in a computer network, where the first configuration has a virtual local area network (VLAN)-to-instance (VI) mapping that maps each of one or more VLANs to one of one or more MST instances in the MST region. The switch may subsequently receive a second MST region configuration that has a different VI mapping than the first configuration, and may determine one or more VLANs of the second configuration that have a different VI mapping from the first configuration (“affected VLANs”). Accordingly, in response to a trigger to apply the second configuration at the switch, the affected VLANs are blocked for a delay, and the second configuration may be applied at the switch without restarting the MST process.

Abstract: Embodiments provide a method, network device, and computer program product for optimizing traffic in a link-state network distributed across a plurality of sites. The method, network device, and computer program product include receiving a multi-destination message at a first node within the link-state network. Additionally, the method, network device, and computer program product include identifying a plurality of multi-destination trees within the network, each tree having a respective root node. The method, network device, and computer program product determine a plurality of cost values corresponding to each of the plurality of multi-destination trees, based on one or more links along a shortest path from the first node to the respective root node of each tree. Based on the determined cost values, the method, network device, and computer program product select one or more of the multi-destination trees and transmit the multi-destination message using the selected tree.

Abstract: In one embodiment, a spanning tree protocol (STP) is executed to assign a first port of an intermediate network device to a Root Port Role, a second port of the intermediate network device to an Alternate Port Role, a third port of the intermediate network device to a Designated Port Role, and a fourth port of the intermediate network device to a Backup Port Role. At least one bridge protocol data unit (BPDU) message is periodically sent from the first port assigned Root Port Role, the second port assigned Alternate Port Role and the fourth port assigned Backup Port Role, irrespective of receipt of any BPDU messages from neighboring intermediate network devices. In response to a failure to receive a BPDU message from a neighboring intermediate network device on the third port assigned Designated Port Role within a threshold amount of time, one or more actions are taken.

Abstract: A system and method runs a multiple spanning tree protocol (MSTP) in a computer network having a very large number of bridge domains. The computer network includes a plurality of intermediate network devices, each having a plurality of ports for forwarding network messages. Within each device, a plurality of bridge domains are defined, each bridge domain is identified by a Virtual Local Area Network (VLAN) Identifier (VID), and one or more device ports. For each port, a separate mapping of VIDs to Multiple Spanning Tree Instances (MSTIs), based on the bridge domains defined at the port, is established. Each mapping is converted to a port-based configuration digest, which is entered into Spanning Tree Protocol (STP) control messages sent from the respective port. Ports receiving STP control messages whose configuration digest values that match the configuration digests values computed for the ports are said to be in the same Multiple Spanning Tree region.

Abstract: A system and method assures the proper and continued operation of intermediate network devices, such as bridges, in a computer network. The bridge includes a spanning tree protocol (STP) engine, which is configured to have a bridge assurance (BA) sub-engine. The STP engine assigns the bridge's ports to one of a Root, Alternate, Designated or Backup Role. The BA sub-engine directs the STP engine to issue configuration messages from all ports to which neighboring bridges are coupled, including ports assigned to the Root and Alternate roles. The BA sub-engine further looks for the receipt of BPDU messages from neighboring bridges and employs one or more timers to determine whether the neighboring bridges are continuing to operate properly.

Abstract: In one embodiment, each network interface of a network device in a computer network may be classified as either a low-speed interface (e.g., wireless) or a high-speed interface (e.g., wired). Illustratively, then, low-speed interfaces may be configured (identified) as external interfaces to external links and high-speed interfaces may be configured (identified) as internal interfaces to internal links. By executing a multiple spanning tree (MST) protocol at the network device with other network devices in the computer network, network devices interconnected with internal links are in a same MST region and internal links within an MST region are preferred over external links between MST regions.

Abstract: In one embodiment, in response to receiving a topology change notification at a network bridge having ports identified as either a network port or an edge port, address learning may be disabled on the network bridge. Once address learning is disabled, an association of all entries of a forwarding table of the network bridge having addresses previously forwarded on a particular network port of the network bridge may be changed to forward those addresses on all network ports of the network bridge (e.g., flooding the frames not addressed to edge ports on all network ports only). Subsequently, address learning may be enabled on the network bridge, thus repopulating the network port entries of the forwarding table in response to the topology change.

Abstract: In one embodiment, a network device receives on a first port a first spanning tree protocol (STP) control message including a first path-tracking field corresponding to a given spanning tree instance in a network. The first path-tracking field includes a value based on one or more other network devices that have propagated the first STP control message. The network device receives on a second port a second STP control message including a second path-tracking field corresponding to the given spanning tree instance. The second path-tracking field includes a value based on one or more other network devices that have propagated the second STP control message. The network device utilizes the values from the first path-tracking field and the second path-tracking field to select a root port for the given spanning tree instance.

Abstract: In one embodiment, a bridge may receive a first convergence proposal on a root port from an upstream adjacent bridge of a computer network, and in response, may transmit a second convergence proposal downstream on each non-edge designated port of the bridge without syncing the non-edge designated ports. The bridge may then return a convergence agreement to the adjacent bridge in response to the non-edge designated ports having received a returned convergence agreement (or in response to having only edge designated ports). Also, according to embodiments, the adjacent bridge blocks a link to the root port until the convergence proposal(s) and agreement(s) travel end-to-end.

Abstract: In one embodiment, a first multiple spanning tree (MST) region configuration for an MST process may be maintained at a switch in a computer network, where the first configuration has a virtual local area network (VLAN)-to-instance (VI) mapping that maps each of one or more VLANs to one of one or more MST instances in the MST region. The switch may subsequently receive a second MST region configuration that has a different VI mapping than the first configuration, and may determine one or more VLANs of the second configuration that have a different VI mapping from the first configuration (“affected VLANs”). Accordingly, in response to a trigger to apply the second configuration at the switch, the affected VLANs are blocked for a delay, and the second configuration may be applied at the switch without restarting the MST process.

Abstract: In one embodiment, each network interface of a network device in a computer network may be classified as either a low-speed interface (e.g., wireless) or a high-speed interface (e.g., wired). Illustratively, then, low-speed interfaces may be configured (identified) as external interfaces to external links and high-speed interfaces may be configured (identified) as internal interfaces to internal links. By executing a multiple spanning tree (MST) protocol at the network device with other network devices in the computer network, network devices interconnected with internal links are in a same MST region and internal links within an MST region are preferred over external links between MST regions.

Abstract: In one embodiment, when a frame is directed to one or more customer instance ports (CIPs) of a switch having received the frame, the frame (a “local frame”) may be forwarded on the one or more CIPs based on only a customer space (C-space) lookup operation. Also, if the frame is not directed to any CIPs of the switch, the frame (a “transient frame”) may be forwarded on at least one or more provider backbone ports (PBPs) of the switch based on only a backbone space (B-space) lookup operation. For example, a unicast frame may be forwarded based on whether the frame terminates at the switch having received the frame (to a CIP of the switch), while a multicast frame may be forwarded based on determining whether an instance service identifier (I-SID) of the frame maps to a local VLAN ID (L-VID) at the switch (to any CIPs servicing that L-VID).

Abstract: In one embodiment, a first port of a bridge is configured for a first spanning tree (ST) and not a second ST, while a second port of the bridge is configured for the second ST and not the first ST. A multiple ST (MST) bridge protocol data unit (BPDU) for the first and second STs is generated for the first and second ports having a first portion corresponding to the first ST and a second portion corresponding to the second ST. To translate MST instances, the second portion is stripped from the MST BPDU of the first port, and the first portion from the MST BPDU of the first port is associated with the second ST. Conversely, the first portion is stripped from the MST BPDU of the second port, and the second portion from the MST BPDU of the second port is associated with the first ST.

Abstract: In one embodiment, when a frame is directed to one or more customer instance ports (CIPs) of a switch having received the frame, the frame (a “local frame”) may be forwarded on the one or more CIPs based on only a customer space (C-space) lookup operation. Also, if the frame is not directed to any CIPs of the switch, the frame (a “transient frame”) may be forwarded on at least one or more provider backbone ports (PBPs) of the switch based on only a backbone space (B-space) lookup operation. For example, a unicast frame may be forwarded based on whether the frame terminates at the switch having received the frame (to a CIP of the switch), while a multicast frame may be forwarded based on determining whether an instance service identifier (I-SID) of the frame maps to a local VLAN ID (L-VID) at the switch (to any CIPs servicing that L-VID).

Abstract: In one embodiment, a network device receives on a first port a first spanning tree protocol (STP) control message including a first path-tracking field corresponding to a given spanning tree instance in a network. The first path-tracking field includes a value based on one or more other network devices that have propagated the first STP control message. The network device receives on a second port a second STP control message including a second path-tracking field corresponding to the given spanning tree instance. The second path-tracking field includes a value based on one or more other network devices that have propagated the second STP control message. The network device utilizes the values from the first path-tracking field and the second path-tracking field to select a root port for the given spanning tree instance.

Abstract: In one embodiment, in response to receiving a topology change notification at a network bridge having ports identified as either a network port or an edge port, address learning may be disabled on the network bridge. Once address learning is disabled, an association of all entries of a forwarding table of the network bridge having addresses previously forwarded on a particular network port of the network bridge may be changed to forward those addresses on all network ports of the network bridge (e.g., flooding the frames not addressed to edge ports on all network ports only). Subsequently, address learning may be enabled on the network bridge, thus repopulating the network port entries of the forwarding table in response to the topology change.