Cisco Technology, Inc.

Stefano Binetti

Luca Della Chiesa

Gilberto Loprieno

Stefano Piciaccia

Hiroshi Suzuki

Sudhir Kayamkulangara

David Bianchi

Rayen Mohanty

Giovanni Osnago

Norman William Finn

Mohammed Ismael Tatar

Sharat C Prasad

Paolo Sironi

Maurizio Gazzola

Cedrik K Begin

Sandesh K Rao

Shreeram Bhide

Pagalavan Krishnamoorthy

Chien Fang

Marinica Rusu

Walid Wakim

Sitaram Dontu

Gary Nicholl

Emanuela Grandi

Shankar Venkataraman

Theodore Kupfer

Sreenivas Makam

Maruizio Gazzola

Embodiments for adaptive inline modulation tuning for optical interfaces is described. The inline modulation tuning is provided by optical nodes, where the optical nodes exchange optical modulation information and node ability information between optical devices in a node pair. An optimal modulation scheme for the node pair is selected based on modulation abilities of each node and associated transceiver, as well as a link quality and performance observed for the optical link.

Adaptive inline modulation tuning for optical interfaces

A first network element includes trail trace identifier information in an optical network frame. The first network element obtains data to transmit over an optical network link to a second network element. The first network element generates an optical network frame with alignment marker bytes, which are followed by padding bytes. The optical network frame also includes overhead bytes following the padding bytes. The overhead bytes include a Multi-Frame Alignment Signal (MFAS) byte, a link status byte, and reserved bytes. The optical network frame also includes a payload bytes following the overhead bytes. The payload bytes encode at least a portion of the data to transmit to the second network element. The first network element inserts trail trace identifier information into the reserved bytes in the overhead bytes. The trail trace identifier information identifies the first network element as a source of the optical network frame.

Access point identifiers in 400ZR and 400ZR+ protocols

A method of obtaining a measure of asymmetry between optical fibers of a forward and reverse paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes receiving, at first and second arrival times, from a first optical network device, a first optical signal transmitted on a first optical fiber and a second optical signal transmitted on a second optical fiber, calculating a first time difference between the second arrival time and the first arrival time. The method includes determining a measure of asymmetry between the first optical fiber and the second optical fiber based on the first time difference and a second time difference between a first time of transmission by the first optical network device of the first optical signal and a second time of transmission by the first optical network device of the second optical signal.

Measuring fiber asymmetry

A method, system, and computer-readable medium for a network interface with adjustable rate are disclosed. For example, one method involves receiving a request to activate a virtual lane of an interface, where the request is received by a first node. The interface is configured to facilitate data communication between the first node and a second node, and the interface includes a plurality of virtual lanes that include at least one active virtual lane, and at least one inactive virtual lane. The method also involves, in response to receiving the request, negotiating with the second node to select an additional virtual lane from the at least one inactive virtual lane. The method involves activating the additional virtual lane. After the activating, the first node and the second node are configured to use the active virtual lane(s) and the additional virtual lane for data communication.

Network interface with adjustable rate

In one embodiment, a working path through a packet switched network is protected by a protection path. In response to a switchover condition, a packet switching device ceases to enqueue packets for sending over the current working path. Packets are enqueue for sending over the protection path, with a delay by a predetermined duration before beginning to dequeue and send of packets over the protection path. A sending packet switching device, by delaying an appropriate predetermined duration, can guarantee that the protection switching operation will not induce packet reordering nor packet loss. This predetermined delay is calculated, possibly based on measurements, of different component delays of sending packets over the working and protection paths. For example, these component delays typically include latency within the sending device, latency of communications between the sending device and the destination, and latency with the destination.

Switching to a protection path without causing packet reordering

Packets of various protocols may contain timestamps generated by a single timestamp engine. In one embodiment, packets of two different protocols, which are referred to as Protocols A and B for simplicity, contain timestamps generated by the same Protocol B timestamp engine. In order to cause a Protocol B timestamp engine to produce a timestamp for a Protocol A packet, information can be provided to the Protocol B timestamp engine indicating that the Protocol A packet is a packet of Protocol B. The information can be provided by an internal header appended to the Protocol A packet that effectively misidentifies the Protocol A packet as a Protocol B packet. As a result, the Protocol B timestamp engine generates and inserts a timestamp for the Protocol A packet as if it were a Protocol B packet. The Protocol A packet, now including the timestamp, can be output or further processed.

Single timestamp engine for generating timing information for inclusion in packets complying with multiple networking protocols

Synchronization techniques for multiple clock domains from two or more clients or common pluggable interfaces connected to multiple interfaces on one or more ingress line cards to multiple interfaces on one or more egress line cards are provided. The plurality of clock domain information from the clients that are connected on the ingress side is transmitted to the egress line cards. Two or more egress interfaces generate different clocks that are synchronized to the multiple clock domains.

Egress clock domain synchronization to multiple ingress clocks

Various systems and methods that allow multiple aggregation protocol sessions to be established in a daisy chain network are disclosed. One method involves sending a first aggregation protocol packet and a first session identifier associated therewith to a first network device via a first interface and sending a second aggregation protocol packet and a second session identifier associated therewith to a second network device via the first interface.

Multiple aggregation protocol sessions in a daisy chain network

Systems and methods for unidirectional communication in an optical network employing bidirectional transponders are provided. The modulation and amplification capabilities of the bidirectional transponder are used to forward information to the next node. In this way a highly cost-effective 'drop and continue' architecture is provided. In one implementation, the client-side output of the bidirectional transponder is looped back to the client-side input using, e.g., a Y-cable fiber. In this way, a unidirectional signal present on a network-side input wavelength to the transponder is presented both on a network-side output wavelength of the transponder and at the same time to a client. The modulation and amplification capabilities of the bidirectional transponder are thus exploited in forwarding the unidirectional signal to the next node.

Unidirectional drop and continue using bidirectional transponder

Systems and methods for operating transponders that automatically accommodate multiple received signal types. The different signal types may include different clients such as, e.g., SONET/SDH, G.709, 10 Gigabit Ethernet, etc. as well as different data rates. A transponder can automatically detect the client signal type and data rate and respond by processing the received signal appropriately, notifying a control processor, and invoking an appropriate performance monitoring method. This maximizes the network operator's flexibility and ease of configuration.

Automatic selection of the performance monitoring based on client type

Methods and apparatus for processing a failure and a subsequent recovery in a ten Gigabit Ethernet (GE) optical transport network (OTN) wave division multiplexing (WDM) ring are disclosed. According to one aspect of the present invention, a device includes a plurality of ports, a sensing arrangement, and a processing arrangement. The ports include a first port that is initially configured to be in a forwarding state, and the sensing arrangement identifies whether the first port is facing or interfaced with a failure associated with the network ring. The processing arrangement being generates at least a first G.709 frame, and inserts at least one bit into the first G.709 frame that indicates that the failure associated with the network ring has been identified if the first port is facing a failure. The processing arrangement forwards the first G.709 frame through the second port.

Recovery mechanism for 10 GE optical transport network wavelength division multiplexing ring

A method of processing Ethernet signals for transport in an optical network system is disclosed. The method includes encapsulating Ethernet frames into EFP frames comprising a length header, a converged data link header, and a data area, and mapping the EFP frames into byte synchronous paths. The converged data link header replaces an Ethernet preamble of the Ethernet packet.

Efficient framing procedure for variable length packets

Techniques for providing ADM functionality to an optical (OTN/DWDM) ring are provided. A pair of muxponder components are utilized to form a transparent ADM. In one muxponder, transmit signals are sent in a first direction and receive signals are received from a second direction. In the other muxponder, transmit signals are sent in the second direction and received from the first direction.

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Monza, Italy

Stefano Binetti