Abstract: In general, this disclosure describes techniques that may allow multiple spanning tree networks to be joined across a ring network. In a ring topology, e.g., an Ethernet ring topology, there are multiple nodes connected one to another to form a ring. Subtending from the ring network are customer devices that may joined together to form networks, e.g., Ethernet networks. Providing only a single connection between a subtending network and the ring network risks isolating the subtending network from the ring network if a fault occurs on the connecting link. Providing two links between a subtending network and the ring network, however, may create an undesirable traffic loop. One example protocol used by the customer devices to communicate with one another in a network and prevent looping paths is Spanning Tree Protocol.

Abstract: In general, techniques are described for implementing a virtual snooping bridge in computer networks. The techniques may be implemented by a ring network comprised of a plurality of ring network devices arranged in a ring topology. In one aspect, a ring network device coupled to an adjacent device that provides access to multicast content implements the techniques. This ring network device comprises one or more ports and a control unit. The ports receive ring messages from one or more of the other ring network devices in accordance with a group management ring protocol (GMRP). The ring messages indicate operations requested by one or more host devices with respect to delivery of content of the multicast group. The control unit then presents the received operations to the adjacent network device such that, from the perspective of the adjacent network device, the ring network appears as a single layer two network device.

Abstract: In general, this disclosure describes network security techniques that may accommodate legitimate movement of a subscriber device while preventing MAC collisions that may result from configuration errors or MAC spoofing attempts. MAC spoofing may result in packets directed to one subscriber device being sent instead to another subscriber device. By modifying an access node or a Dynamic Host Configuration Protocol (DHCP) server to allow only authorized subscriber devices on the access network, layer two collisions (“MAC collisions”) may be prevented.

Abstract: The disclosure describes communication of information between a network interface device and subscriber devices over a power line. A UPS unit receives operating power from subscriber premises via a first power line and delivers operating power to the network interface device via a second power line. The network interface device transmits and receives information, such as voice, video and data, to and from the UPS unit via the second power line. The UPS unit receives the information transmitted by the network interface device via the second power line, and transmits the received information to subscriber devices within the premises via the first power line. The UPS unit receives information transmitted by subscriber devices via the first power line, and transmits the received information to the network interface device via the second power line. The first and second power lines each serve as both a power line and a communication medium.

Abstract: In general, techniques are described for performing grant scheduling in optical networks. An optical line terminal (OLT) comprising a control unit may implement the techniques. The control unit determines an amount of upstream data associated with a category of service that is waiting at a first one of a plurality of ONTs to be transmitted upstream to the OLT and computes a number of GCPs for each of the ONTs based on a determined amount of data associated with the category of service that is waiting to be transmitted upstream to the OLT for each of the ONTs. After computing the number of GCPs, the control unit then grants time slots to the one or more of the ONTs based on the number of GCPs computed for each of the ONTs, wherein the time slots comprise time slots for upstream communication form the ONTs to the OLT.

Abstract: In general, techniques are described for monitoring downstream traffic in order to schedule delivery of upstream traffic in a computer network. The techniques may be implemented by an optical line terminal (OLT) comprising a control unit and an interface. The control unit determines an amount of upstream data that is waiting at one of a plurality of ONTs to be transmitted upstream to the OLT, and determines an amount of downstream data that is transmitted by the OLT to this ONT. The control unit increases the determined amount of upstream data based on the determined amount of downstream data transmitted by the OLT to the ONTs and, after increasing the determined amount of upstream data, generates an upstream grant map that grants time slots to the ONTs based on the determined amount of upstream data. The interface transmits the upstream grant map downstream to the ONTs.

Abstract: In general, techniques are described for inline packet replication in network devices. A network device referred to as an optical line terminal (OLT) may implement the techniques. The OLT comprises a customer interface that supports different logical interfaces to which couple a plurality of optical network terminals (ONTs) and a network interface that receives a data unit. The OLT further comprises a conversion unit, such as a media access control (MAC) module, located in a data path of the optical line terminal that determines whether the received data unit is a candidate for replication. The conversion unit includes an inline packet processing module that performs replication to generate at least one copy of the data unit based on the determination that the received packet is a candidate for packet replication. The customer interface outputs the at least one copy of the data unit to the ONTs.

Abstract: In general, this disclosure describes techniques that may allow detection of a missing control node on a ring network and selection of a single node on ring network to act as the control node. In one example, a method includes receiving, at a first node in a ring network, a data unit transmitted by a second node in the ring network, the data unit including an identifier that identifies the second node. The method further includes comparing the identifier of the second node to an identifier that identifies the first node, and automatically selecting one of the first node and the second node as a control node for the ring network based on the comparison.

Abstract: In general, techniques are described for interworking between Ethernet organization, administration, and maintenance (OAM) frames and Asynchronous Transfer Mode (ATM) ATM OAM cells. For example, an access node in an Ethernet and ATM network may implement the techniques. The access node comprises an Ethernet interface that receives an Ethernet OAM Loopback frame from a device within an Ethernet network. The access node includes a control unit that constructs an ATM OAM End-to-End Loopback cell from the Ethernet OAM Loopback frame, and an ATM interface that transmits the ATM OAM End-to-End Loopback cell from the access node towards a virtual circuit connected to a subscriber device to verify connectivity from the originating device within the Ethernet network to the subscriber device within the ATM network.

Abstract: In general, this disclosure relates to maintaining security between an optical network terminal (ONT) and an optical network aggregation device in an Active Ethernet network. An optical network aggregation device includes one or more optical Ethernet switches that can be adaptively configured to support authentication of one or more ONTs. For example, the optical network aggregation device may include a controller with an authentication unit for managing ONT authentication and an optical Ethernet interface for transmitting and receiving data over the optical network. The authentication unit may exchange authentication request messages via the optical Ethernet interface with an ONT and grant the ONT access to the provider network based on the exchange, thereby preventing rogue devices from gaining access to the provider network.

Abstract: This disclosure describes ONT-based management of micronodes in an RFOG network. A micronode is configured to permit remote management via an ONT in an optical network. An optical networking protocol, such as a PON protocol, may be used to exchange information with an ONT for management of the micronode. Management may include configuration and monitoring of the micronode. The micronode may have a management interface that supports remote configuration and monitoring via an ONT coupled to the management interface. An operator may use the ONT as a management terminal for the micronode. The ONT may permit an operator to effectively manage micronodes, and also may offer a ready upgrade path to provide optical networking services such as PON services to a subscriber when the operator is ready to upgrade its CO equipment and CPE.

Abstract: Systems and methods for multicast admission control are provided. In one embodiment, a node comprises: a first interface configured to receive a multicast channel access request, from a subscriber interface, including an address for a channel; a memory including a subscriber profile and VLAN configuration data for the network; a processor that identifies a first VLAN corresponding to the address from the VLAN configuration data and determines whether the subscriber is authorized to receive the channel via the first VLAN based on access policy designated by the subscriber profile; wherein the processor further determines whether granting access to the channel violates admission control policy based on predefined bandwidth requirements and/or a stream count limit for the first VLAN; wherein when the subscriber interface is authorized to receive the channel and when granting access to the channel does not violate admission control policy, the processor routes the channel to the subscriber.

Abstract: This disclosure is directed to techniques for facilitating clock recovery in optical networks. An optical network terminal (ONT) that terminates a fiber link of an optical network includes a clock mode selection module that automatically selects a clock recovery mode based on a type of optical network to which the ONT connects and a type of service provided to one or more subscriber devices coupled to the ONT. By automatically selecting the clock recovery module, an administrator or other user need not provision this aspect of the optical network, thereby reducing administrative tasks and facilitating the provisioning of the optical network. In addition, the techniques enable selection of the most optimal clock recovery mode based on the current state of the optical network.

Abstract: This disclosure relates to detection of optical fiber failure and implementation of protection switching in a passive optical network (PON). A protection switch determines whether there is an optical fiber failure in a fiber link between an OLT and a group of ONTs. In the case of an optical fiber failure, an optical fiber may be physically cut or damaged, causing the optical fiber link to be disabled. A protection switch may detect an optical fiber failure by determining a peak optical power of at least a portion of an upstream optical signal transmitted from one or more ONTs via the optical fiber link. If the peak optical power is less than a threshold value, the protection switch may detect a fiber failure. In response to a detected fiber failure, the protection switch may switch upstream and downstream PON transmissions from a primary optical fiber to a secondary optical fiber.

Abstract: The invention is directed to an optical network terminal (ONT) for use in a passive optical network (PON) that provides reliable battery status reporting and, optionally, remote monitoring and configuration of an uninterruptible power supply (UPS) unit. In particular, the UPS unit provides power to the ONT via a power line and transmits data to the ONT via the power line. Generally, the described invention supports one-way or two-way communication of status, alarm, and configuration signals using a single power line. Specifically, such signals may be transmitted over the power line by inserting a carrier frequency, such as a carrier frequency of approximately 1 MHz, onto the power line. In this manner, the invention may provide a simple battery status monitoring system while also reducing the cost of installation.

Abstract: In general, techniques are described for providing an isolation virtual local area network (VLAN) for layer two access networks. A server comprising an interface and a control unit may implement the techniques. The interface receives a message that initiates a request for a layer three (L3) network address for use by a client device via an isolation virtual local area network (VLAN) that supports transmitting data from a network device to the server, where the network device is intermediately positioned between the client device and the server. The message includes a layer two (L2) address associated with the client device. The control unit determines whether to allow the client device to access the network and assigns the L3 network address to the client device based on the determination.

Abstract: Techniques are disclosed that relate to synchronizing a clock on a network interface device with a clock on an optical line terminal (OLT). In one example, the technique to synchronizing the clocks may include monitoring one or more instances when the network interface device transmits information to the OLT and determining when a frame should be received by the network interface device based on the monitored one or more instances when the network interface device transmits information the OLT.

Abstract: In general, techniques are described for provisioning network devices in an Ethernet-based access network. For example, an access node located in an Ethernet-based access network positioned intermediate to a back office network and a customer network may implement the techniques. The access node comprises a control unit that discovers a demarcation point device that terminates the access network of the service provider network at the customer network. The control unit of the access node implements an Ethernet protocol to provide layer two network connectivity between the service provider network and the customer network, authenticates the demarcation point device based on a unique identifier assigned to the demarcation point device and, after successfully authenticating the demarcation point device, provisions the demarcation point device.

Abstract: Techniques are disclosed that restrain cables in order to relieve excessive tensile force and to prevent breakage at a point of termination. In one example, a system includes a clip and a receiver configured to receive the clip. The clip includes a first member and a second member pivotally connected to each other by a hinge, the hinge located intermediate opposed ends of the first member and the second member, the hinge defining a groove for receiving a first portion of the cable.

Abstract: This disclosure is directed to devices and methods for facilitating the upgrade of optical networks. An optical network terminal (ONT) that terminates an optical fiber link of an optical network comprises two or more transport engines that each converts data transmitted via different transports to data corresponding to a service. For example, the ONT may include a first transport engine and a second transport engine. The first transport engine converts data received over the optical network via a first transport, e.g., a legacy transport, into data corresponding to a service for one or more subscriber devices. The second transport engine converts the data received over the optical network via a second transport, e.g., a next generation transport, into the data corresponding to the service for the subscriber devices. The ONT is selectively configurable to select one of the first and second transport engines, thereby making the ONT upgrade-resilient.