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: 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: In general, the disclosure describes network techniques that may automatically assign virtual local area networks (VLANs) to domains in a ring network. In one example, a method includes receiving, by a control node in a ring network, a plurality of data units transmitted by a plurality of transport nodes on the ring network, each data unit comprising profile information, and automatically assigning a VLAN to one of a plurality of domains established on the ring network based on the profile information.

Abstract: In general, this disclosure relates to optical network devices with support for multiple physical layer transport standards. An optical network device may include an optical receiver that can be adaptively configured to support different physical layer transport standards. For example, the optical receiver may include a photodiode and a control unit to adjust a characteristic of the photodiode to support different optical physical layer transport standards on an adaptive basis. For example, the control unit may adjust the photodiode characteristic to prevent an overload condition when an optical signal is received according to the physical layer access standard.

Abstract: This disclosure is directed to techniques for facilitating return path compliance in networks. A device, such as an optical network terminal (ONT), may, for example, buffer a digital representation of an upstream analog signal to facilitate return path compliance specified by a Data Over Cable Service Interface Specification (DOCSIS) 3.0 standard. The ONT may comprise a first conversion module that converts an upstream analog signal into a corresponding digital signal and a signal detection module that determines whether the upstream analog signal represents a valid upstream communication. The device may further comprise a buffer that buffers the corresponding digital signal while the signal detection module makes the determination, a second conversion module that converts the buffered digital signal into a reconverted upstream analog signal upon the determination that the upstream analog signal is valid and a laser that transmits the reconverted upstream analog signal via a fiber optical cable.

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, 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: 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: In general, techniques are described for applying adaptive thresholds to multicast streams within computer networks. For example, an access node may implement the techniques to facilitate efficient delivery of multicast streams. The access node comprises an interface that couples to a subscriber network having a subscriber device. The access node also includes a control unit that determines a multicast stream count reflecting current delivery of multicast streams to the subscriber network and a threshold value based on historical multicast stream counts delivered to the subscriber. The interface receives a message requesting to join a multicast group in accordance with a multicast management protocol. In response to this message, the control unit determines a projected stream count based on the above current multicast count. The control unit then compares the projected stream count to the threshold value, and admits the subscriber device to the multicast group based on the comparison.

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: 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 describes techniques for providing a communication path for upstream communications originating from a node of an optical network. In particular, methods and devices are described for combining upstream communications originating from the node of the optical network with upstream communications originating from subscriber devices coupled to the node. The upstream communication originating from the node may, for example, include status information about the node. The upstream communication, which may include status information about the node, essentially piggy-backs onto upstream communication originating from the subscriber devices coupled to the node.

Abstract: The disclosure describes an active network interface device (NID) enclosure having a modular construction that provides flexibility to a vendor and permits independent access to technician-accessible connections and subscriber-accessible connections while promoting resistance to environmental and security threats. The active NID enclosure includes an electronics enclosure and an access enclosure. The electronics enclosure contains active electronic components for conversion of data carried on a network signal carrier into services for delivery to subscriber devices. The access enclosure includes two separate access compartments, having separate covers, for independent access to either network terminals or subscriber terminals.

Abstract: Techniques are described for managing traffic flow to an optical network terminal (ONT) on a passive optical network (PON) to prevent an individual ONT from being overrun. Specifically, the techniques involve reducing a transmission rate of a unique traffic flow and selectively denying access to a common traffic flow. By reducing the transmission rate of the unique traffic flow, sufficient bandwidth may be released to receive the unique traffic flow and the common traffic flow without overflowing the ONT. For example, the ONT or, alternatively, the OLT may send the requested common traffic flow without reducing the transmission rate of the unique traffic flow when sufficient bandwidth is available, send the common traffic flow but reduce the transmission rate of unique traffic flow by an appropriate amount, or deny access to the common traffic flow altogether without reducing the transmission rate of the unique traffic flow.

Abstract: The invention is directed to a pluggable module and mounting socket for use in an optical network terminal (ONT). In particular, the mounting socket accepts a pluggable module comprising either a dual-section triplexer card or a single-section diplexer card, thereby allowing a vendor to selectively change the type of PON transport by simply changing the diplexer/triplexer pluggable module to support either diplexer or triplexer applications. The ability to configure the ONT by swapping out the pluggable diplexer/triplexer module eliminates the need for a manufacturer to maintain two different versions of the ONT, i.e., with or without video.

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: The disclosure is directed to techniques for merging multiple data flows in a Passive Optical Network (PON). The PON comprises an interface module and a plurality of network nodes connected to the interface module via an optical fiber link. Each of the network nodes further serves client devices. The client devices request multiple data flows, requiring the interface module to serve multiple data flows to a network node for delivery to the devices. The interface module merges received data flows to permit multiple flows to be processed by a single segmentation and reassembly (SAR) engine, reducing hardware cost and complexity within the node. However, subunits associated with different data flows within a merged data flow are not interleaved with one another. Instead, the subunits associated with an original unit of information are transmitted contiguously within the merged data flow, facilitating identification and reassembly of the subunits for a particular microflow.

Abstract: A method of creating a signal encoded with a message for transmission from a line unit to a switch unit in a network element of a communication network includes arranging in the message a plurality of contiguous bytes of traffic and arranging in the message a plurality of contiguous nibbles of signaling wherein there is one nibble of signaling for each byte of traffic.

Abstract: Assignment of network addresses, e.g., IP addresses, to network nodes in a passive optical network (PON) may involve assignment of IP addresses within a common subnet scope to network nodes coupled to different optical fiber links and different interface modules in the PON. In this manner, excessive waste of IP addresses can be avoided. Instead of assigning an entire subnet scope of addresses to the nodes coupled to a single optical fiber link, a common subnet can be allocated across a PON having multiple, independent interfaces, increasing the number of subnet IP addresses that are actually used. Accordingly, the IP address space within a subnet scope can be distributed more efficiently. In addition to conserving IP addresses, the number of subnets allocated by ISPs can be reduced, along with the significant expense incurred by ISPs in reserving and maintaining multiple class C subnets.

Abstract: Techniques for reestablishing network address associations upon recovery of a passive optical network (PON) disablement rely on storage address association information. A network node stores address association information in non-volatile memory upon detecting a network disablement. Upon recovery of the PON from the disablement, the network node associates network addresses to clients in accordance with the address association information. The network node may further verify the associations by sending ARP queries for the network addresses to the associated clients. Alternatively, the network nodes may reestablish the address associations by tracking the length of time of the network disablement, and updating address association information in accordance with the length of the disablement.