Ciena

About: Ciena is a company organization based out in Hanover, Maryland, United States. It is known for research contribution in the topics: Signal & Node (networking). The organization has 1259 authors who have published 1557 publications receiving 25989 citations.

Spanning tree flooding backbone systems and methods for link state routed networks

Abstract: The present disclosure provides systems and methods for a spanning tree topology used as a “flooding backbone” for control messages on a link state routed network. Specifically, control messages are only broadcast on the flooding backbone thereby significantly reducing message flooding. The present disclosure also provides systems and methods for correctly and efficiently reconfiguring/fixing the spanning tree topology in the event of any spanning tree link failures without re-running the spanning tree protocol.

Technique for computing pathways in a multi-stage switch fabric through exploitation of symmetrical links

Abstract: A switch fabric for switching data traffic according to a plurality of links. The data traffic may convey audio information, video information, or any other type of information. The switch fabric includes input, output and at least one intermediate stages, each stage including a plurality of switching elements. The switching elements of the input and output stages respectively have external input and output ports. The switch fabric further includes a switch fabric controller. The switch fabric controller includes a link database including information about the plurality of links. The switch fabric controller is operative to search the link database to identify symmetrical links and to establish internal pathways between the input stage and the output stage through the at least one intermediate stage, wherein at least two symmetrical links identified by the searching are realized using a common switching element of the at least one intermediate stage.

Semi-transparent time division multiplexer/demultiplexer

Abstract: A semi-transparent time division multiplexer/demultiplexer that transmits low rate tributaries from one location to another using a high rate aggregate connection, while preserving substantially all of the TOH and payload for each tributary signal. Transparency of the tributary TOH is accomplished by interleaving both the TOH and the Payload of each tributary into the high rate aggregate signal. Some TOH bytes may be tunneled or re-mapped into unused/undefined TOH locations in the aggregate signal to allow transparency of the TOH without corrupting the aggregate. Errors may be handled by tunneling BIP bytes into unused/undefined aggregate locations and updating the tunneled bytes with error masks calculated at each network elements. Alternatively errors may be forwarded by using an error mask generated from the tributary BIP locations and inserting the mask into the associated aggregate BIP locations. The mask in the aggregate BIP is updated with error masks calculated at each network elements. Re-timing of TOH to a synchronized clock in the tributary framer circuits can be accomplished using controlled slips of overhead frames, whereby an entire frame is dropped or added depending on the relationship of the received clock and the synchronized clock. DCC bytes may be re-timed by adding or deleting flag bytes occurring between respective DCC packets. Re-timing of the aggregate TOH to a transmit clock may be accomplished in a similar manner.

Method and apparatus for determining a fiber plant gain transfer function and utilizing same to control distributed gain

Abstract: Systems and methods for determining the distributed gain properties of a fiber plant are disclosed. A detector, a controller and a memory device are utilized to measure signal levels while the pump power is increased. The controller calculates gain for various pump power levels to construct a gain profile or transfer function which may be, for example, gain as a function of pump power. A gain transfer function is constructed for the particular fiber plant to which optical pump is connected. The constructed gain transfer function relates the output power of the optical pump and the signal gain of the signal travelling in the fiber plant. A controller utilizes the constructed gain transfer function to control the output power of the optical pump to produce a desired amount of signal gain. The gain transfer function may be stored as a look-up table and accessed by the controller to determine the amount of output power corresponding to a desired gain level. By utilizing these techniques the differing gain properties of different fiber plants can be compensated such that a desired gain level is achieved.

MPLS and GMPLS tunnel flap dampening in traffic engineered networks

Abstract: Embodiments of the disclosure are directed to tunnel flap damping in a traffic engineered network. One exemplary method for tracking a re-routing history of Multi-Protocol Label Switching (“MPLS”)/Generalized MPLS (“GMPLS”) tunnels over intervals includes measuring a number of policy-based re-routes during at least one measurement interval; determining a tunnel re-route frequency based on the measurement; comparing the tunnel re-route frequency to a frequency threshold; and determining if the tunnel re-route frequency exceeds the frequency threshold and, if the tunnel re-route frequency exceeds the frequency threshold, delaying at least one tunnel re-route.