Abstract: Methods and apparatus are disclosed for applying multiple Link Aggregation Group (LAG) entities on the same set of physical links, thus making bundling of individual services or conversations possible by the different LAG entities within Link Aggregation. Each LAG entity is configured such that a single physical link is Active and all the other links are Standby. Each LAG entity may be regarded as a “bundle.” Thus the services/conversations are bundled into a LAG entity and are handed-off on the Active link during normal operation. If service hand-off is not possible on the Active link (e.g., due to a failure), then the LAG entity switches over to a Standby link thus the service/conversation is handed-off on that formerly Standby link. Bundling may simplify operations of control and signaling.

Abstract: A method forward Ethernet frames at a node in a network supporting an implementation of shortest path bridging (SPB) protocol is disclosed. The method starts with a shortest path computation for the node (referred to as the computing node). The shortest path computation selects at least a shortest path to each destination node in the network, where a neighboring node on the shortest path to reach each node is recorded. Then it computes a downstream loop-free alternate (LFA) node for a destination node, where the LFA node is downstream of the computing node but not on the selected shortest path to the destination node from the computing node. Then when connectivity to the neighboring node on the computed shortest path is detected to be abnormal, the node forwards an Ethernet frame with a destination media access control (MAC) address corresponding to the destination node through the LFA node.

Abstract: A network interconnect node of an internal network may communicate with an external network interconnect node of an external network, other internal network interconnect node(s) and internal network node(s). The network interconnect node may receive frames from the external network interconnect node and forward them according to a Virtual Local Area Network (VLAN) tagging forwarding process to other internal network interconnect node(s) or internal network node(s) based on whether the network interconnect node is active for the service associated with the frames. The network interconnect node may receive frames from other internal network interconnect node(s) or from internal network nodes and forward them according to the VLAN tagging forwarding process to other internal network interconnect nodes, internal network nodes or the external network interconnect node based on whether the frames are encapsulated frames and/or whether the network interconnect node is active for the service.

Abstract: A flow classification process is used at the edge of the shortest path bridging network to determine a flow label for attachment to a client frame entering the network. Any of several flow labels can be assigned to a client frame traversing the network to a particular egress node, and the flow labels are used by forwarding nodes to select among multiple equal-cost paths. In several embodiments, the flow label is calculated as a function of the client frame contents, which provide an entropy source for randomizing the selection of the flow label. This entropy source comprises the Internet Protocol (IP) header in the client frame, in some embodiments, but may comprise other client frame content in other cases.

Abstract: A method is implemented by a network device to establish an explicit path in a network domain including a plurality of network devices including the network device. The explicit path defines a path for forwarding traffic across the network domain that is generated by a path computation element (PCE) in communication with the network domain. Operations, administration and management (OAM) is provided to support checking the establishment and correctness of the explicit path based on interior gateway protocols. The network device receives an explicit path descriptor (EPD) defining an explicit path configuration including configuration attributes for a maintenance endpoint (MEP) or maintenance intermediate point (MIP) where the EPD is generated and distributed by the PCE. The MEP or the MIP is established according to the EPD, the MEP or MIP to monitor the explicit path. A correctness test is performed to check correctness of the explicit path utilizing the MEP or MIP.

Abstract: A method forward Ethernet frames at a node in a network supporting an implementation of shortest path bridging (SPB) protocol is disclosed. The method starts with a shortest path computation for the node (referred to as the computing node). The shortest path computation selects at least a shortest path to each destination node in the network, where a neighboring node on the shortest path to reach each node is recorded. Then it computes a downstream loop-free alternate (LFA) node for a destination node, where the LFA node is downstream of the computing node but not on the selected shortest path to the destination node from the computing node. Then when connectivity to the neighboring node on the computed shortest path is detected to be abnormal, the node forwards an Ethernet frame with a destination media access control (MAC) address corresponding to the destination node through the LFA node.

Abstract: A method in a network element is provided for improved convergence in a network that includes the network element. The network element is one of a plurality of network elements in the network each of which implement the method. The network element includes a database to store the topology of the network. The topology of the network includes a plurality of network elements and links between the network elements. The method classifies convergence actions for the network element to identify convergence actions that can be implemented prior to complete digest synchronization during a convergence process to simplify and reduce convergence latency once digest synchronization is achieved.

Abstract: A method is disclosed to forward Ethernet frames associated with a service instance at a node (a “forwarding node”) in a network supporting an implementation of a protocol for creating logical loop-free topologies. The method starts with receiving a number of MMRPDUs at the forwarding node from links in the first network (receiving links), where each MMRPDU of the first plurality of MMRPDUs contains a first interested node list including one or more interested nodes identified by MAC addresses. Then a service instance identifier (SID) is identified for the service instance and a first set of MAC addresses interested in the service instance is formed. Then a number of MMRPDUs are sent to links associated with the service instance, where each MMRPDU contains a second set of MAC addresses interested in the service instance. The sending may be accompanied by the node installing filtering at the forwarding node accordingly.

Abstract: A method and system is disclosed to compute and distribute a generalized almost directed acyclic graph (GADAG). The method includes computing, by a network element, a GADAG for the network, where the GADAG is a graph abstraction of the network, where the plurality of network elements are the vertices of the GADAG and links connecting the plurality of network elements are the directed edges of the GADAG. The method continues with assembling a GADAG descriptor based on the computed GADAG, and distributing the GADAG descriptor to a plurality of network elements, where each of the plurality of network elements utilizes the GADAG descriptor to compute maximally redundant trees for forwarding traffic. The method also includes leveraging layer 2 attributes and features for layer 2 deployments and updating redundant trees upon topology change events such that traffic outage is avoided or minimized.

Abstract: A system and method for in-service migration for a Virtual Local Area Network, VLAN, service if a Provider Bridge Metro Ethernet Network, PB MEN, is upgraded to a Provider Backbone Bridge, PBB, MEN or an Internet Protocol/Multi Protocol Label Switching, IP/MPLS, MEN. After the deployment of the new PBB or IP/MPLS technology, a sequence of management actions are performed to configure PBB or IP/MPLS edge nodes to use the new technology as well as the old PB-based technology to support the VLAN service. Both old and new connectivity structures are maintained in the edge nodes during the entire migration process. Customer traffic is then redirected per edge node to the new technology. When each edge node entirely provides the VLAN service under the new technology, the migration is complete.

Abstract: A method in a network element is provided for improved convergence in a network that includes the network element. The network element is one of a plurality of network elements in the network each of which implement the method. The network element includes a database to store the topology of the network. The topology of the network includes a plurality of network elements and links between the network elements. The method classifies convergence actions for the network element to identify convergence actions that can be implemented prior to complete digest synchronization during a convergence process to simplify and reduce convergence latency once digest synchronization is achieved.

Abstract: Methods and apparatus for operating a virtual node in a LAG that includes a first virtual node and a second virtual node are disclosed. The first virtual node includes at least a first fellow node and a second fellow node. In one exemplary method, the first fellow node receives, from the second virtual node, first control information comprising a system ID and first configuration information associated with the LAG. The first control information is compared with reference configuration information representing previously established expected configuration information associated with the LAG. Based on that comparison, and at least one additional criterion, a split brain condition may be determined to exist in the LAG. In a complementary fashion, a fellow node of the second virtual node may be configured to alter its transmitted configuration information depending on whether it is able to communicate with its fellow node in the second virtual node.

Abstract: A method is disclosed that is to be executed for supporting operator commands in a link aggregation group at a network device. The method starts with receiving a local operator command for changing aggregation port priority of the link aggregation group, where the local operator command contains operator command attributes including an operator command aggregation port prioritized list. The method continues with determining that the operator command aggregation port prioritized list is different from a remote aggregation port prioritized list used at the remote network device. The network device then transmits a set of operator command attributes associated with the local operator command to the remote network device and performs the local operator command by setting a local aggregation port prioritized list to be consistent with the operator command aggregation port prioritized list for the link aggregation group.

Abstract: A technique for explicit path control for traffic forwarding in a network comprising multiple nodes is described. A device embodiment comprises a path computation element that is configured to receive, from an edge node, control protocol data units of a control protocol. The path computation element is further configured to determine an explicit path from information contained in the received control protocol data units and to instruct the edge nodes to perform an action to have the explicit path installed in the network.

Abstract: A method is disclosed to forward Ethernet frames associated with a service instance at a node (a “forwarding node”) in a network supporting an implementation of a protocol for creating logical loop-free topologies. The method starts with receiving a number of MMRPDUs at the forwarding node from links in the first network (receiving links), where each MMRPDU of the first plurality of MMRPDUs contains a first interested node list including one or more interested nodes identified by MAC addresses. Then a service instance identifier (SID) is identified for the service instance and a first set of MAC addresses interested in the service instance is formed. Then a number of MMRPDUs are sent to links associated with the service instance, where each MMRPDU contains a second set of MAC addresses interested in the service instance. The sending may be accompanied by the node installing filtering at the forwarding node accordingly.

Abstract: A method is implemented by a network device executing a local computation engine and a link state routing protocol. The local computation engine and the link state protocol support automatic establishment of redundant paths and cautious restoration in a packet network. The method includes receiving an explicit path (EP) type length value (TLV) via a link state routing protocol, executing a shortest path algorithm to obtain a shortest path for loose hops of a path identified by the EP TLV, the shortest path to be a primary path, updating a network graph to prune links of the primary path or bias links of the primary path, and calculating a backup path using the shortest path algorithm on the updated network graph.

Abstract: A method that improves multi-area routed Ethernet network design, in which multipath implementation in each of the areas is independent of each other area to allow optimal network design in each area. The network implements a shortest path bridging medium access control (SPBM) protocol. The areas include a Level 2 (L2) routing area coupled to a Level 1 (L1) routing area via multiple area border bridges (ABBs). The L1 routing area including a backbone edge bridge (BEB) coupled to the ABBs via multiple L1 multipath instances identified by respective backbone VLAN identifiers (B-VIDs). The ABBs receive an advertisement from the BEB that indicates a set of BEB identifiers, each of which identifies the BEB and is associated with a respective B-VID. Each of the BEB identifiers is unique. The ABBs also advertise into the L2 routing area, and translate the B-VIDs based on service identifiers for frames transiting the ABBs.

Abstract: A method in a network element improves load distribution in a network that includes the network element. The network element is one of a plurality of network elements in the network each of which implement a common algorithm tie-breaking process as part of a computation used to produce minimum cost shortest path trees. The network element includes a database to store the topology of the network. A set of service attachment points is mapped to network elements in the topology for services individually associated with an equal cost tree (ECT) set and associated with per service bandwidth requirements. The topology of the network includes a plurality of network elements and links between the network elements. The method generates multiple ECT tree sets for connectivity establishment and maintenance of the connectivity in the network. The method defines a bandwidth aware path selection. The method reduces the coefficient of variation of link load across the entire network.

Abstract: A technique for status change handling in an interconnect node is described, wherein the node comprises a data plane that can assume, per service, a passive or active status. A method aspect in the node comprises transmitting, to another node, a first indication that a change has been or is about to be performed, awaiting, from the other node, reception of a second indication that the data plane in the other node has been set to the passive status, and activating, responsive to the received indication, the data plane of the node from the passive status to the active status. The method aspect in the other node further comprises receiving, from the node, the first indication, passivating, responsive to the receiving step, the data plane being in the active status to the passive status, and transmitting, upon completion of the passivating step, the second indication.

Abstract: A node and a method are described herein for computing forwarding trees to distribute traffic in a network. In addition, a network is described herein that has a plurality of nodes interconnected to one another by a plurality of network links, and each node is configured to perform multiple rounds of forwarding tree computations to distribute traffic load on one or more of the network links to the other nodes.