Data processing: structural design – modeling – simulation – and em – Emulation – Compatibility emulation
Reexamination Certificate
2001-10-31
2004-10-19
Phan, Thai (Department: 2128)
Data processing: structural design, modeling, simulation, and em
Emulation
Compatibility emulation
C703S014000, C359S199200, C359S199200
Reexamination Certificate
active
06807523
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to software emulation of optical communication networks, systems, nodes, modules and components.
2. Description of Related Art
Optical communication systems are a substantial and fast growing constituent of communication networks. The expression “optical communication system,” as used herein, relates to any system which uses optical signals to convey information across an optical waveguiding medium, for example, an optical fiber. Such optical systems include but are not limited to telecommunication systems, cable television systems, and local area networks (LANs). (Optical systems are described in Gowar, Ed. Optical Communication Systems, (Prentice Hall, New York) c. 1993, the disclosure of which is incorporated herein by reference.)
Many optical communication systems are currently configured to carry an optical channel of a single wavelength over one or more optical waveguides. To convey information from multiple sources, time-division multiplexing (TDM) is frequently employed. In TDM, a particular time slot is assigned to each signal source with the complete signal constructed from portions of the signal collected from each time slot. While this is a useful technique for carrying plural information sources on a single channel, its capacity is limited by fiber dispersion and the need to generate high peak power pulses.
While the need for communication services increases, the current capacity of existing waveguiding media is limited. Although capacity may be expanded (e.g., by laying more fiber optic cables), the cost of such expansion is prohibitive. Consequently, there exists a need for a cost-effective way to increase the capacity of existing optical waveguides.
Wavelength division multiplexing (WDM) is now a commonly utilized technique for increasing the capacity of existing fiber optic networks. WDM systems typically include a plurality of transmitters, each respectively transmitting signals on a designated channel or wavelength. The transmitters are typically housed in a first terminal located at one end of a fiber. The first terminal combines the channels and transmits them on the fiber to a second terminal coupled to an opposite end of the fiber. The channels are then separated and supplied to respective receivers within the second terminal.
The WDM system described in the previous paragraph can be perceived as a point-to-point connection with multiple signals carried from one terminal to the other. However, it is frequently advantageous to add and drop channels at various locations between the two terminals. Accordingly, other network elements, such as add/drop modules are often provided along the fiber in order to inject and/or remove channels from the fiber. Moreover, if the fiber extends over long distances, it is necessary to segment the fiber into sections with each fiber section being coupled to another by an additional network element that amplifies the signal (e.g., an erbium doped fiber amplifier).
In addition to the information bearing channels described above, Condict '115 utilizes a service channel at a wavelength different than the information bearing channels and carrying diagnostic and span topology information that can also be transmitted through each span. Information associated with a span may be coupled via Ethernet connections to an internet protocol (IP) router. This IP router passes the information via the Internet to additional IP routers. A local area network (LAN) then transmits the information between the IP routers and to the network monitoring equipment. Finally, information associated with a span is similarly passed to network monitoring equipment through Ethernet links and an IP router.
The Condict '115 patent ensures proper operation of the WDM system by monitoring each network element. In the event of a failure, such as a fiber break, the communication system maintains its ability to monitor each network element by using, for example, a service channel separate from the main optical communication channel. Moreover, the communication system automatically responds to a fault by having each network element identify itself and report information about its operating status. Optical communication networks typically include an optical communication path and a plurality of network elements coupled to the optical communication path. The network elements typically include one or more optical, opto-electrical, electro-optical, or electrical components. A microprocessor-based controller (a.k.a. node control processor (NCP)) runs management and control software that manages, tracks and/or controls various functions of the node hardware.
In other words, the NCP may monitor and/or control hardware components of the node in order to maintain the functionality, tune performance and otherwise manage the optical network. For example, the status of a first optical component may be monitored by the first processor that generates a first electrical signal in accordance with the status of the first optical component. This status info may be used by the controller or transmitted to other controllers in the network in order to manage the component, the node, other components, other nodes, the network, etc. A service channel (e.g. in-band or out-of-band wavelength) is typically used to transmit such status and other management information.
Some of the challenges facing optical communication equipment vendors include development, testing and verification of components, nodes and systems. These tasks are made even more challenging, if not impossible, when the hardware is not available. In other words, some or all of the hardware components in a node may not be available to software engineering and testing groups due to production constraints, unavailability of components, prior commitments to customers, etc. The management and/or control software being written for these components and nodes, however, must be rigorously tested and validated before it can shipped to the customer. Without the necessary hardware to perform such tests, the software development and release may be delayed.
These problems are exacerbated by WDM systems, particularly high channel count WDM systems. For each channel there may be a set of hardware (e.g. transmitter, receiver, or other circuit packs) that is unique to that channel. As the channel count increases so does the number of corresponding circuit packs within network elements. Channel counts currently number about 100 but are expected to increase to several hundreds at least through product line and technology evolution. Thus, it becomes more and more cost prohibitive and logistically difficult to have full systems available in the quantities required for software application (i.e. agents) unit testing, software system integration, and validation testing particularly as the complexity of the system grows and various different types and versions of optical communications modules are developed. If not addressed, these problems potentially could affect product availability and product quality.
Thus, there is a need in the art for emulating certain hardware components of an optical communications so that the corresponding control and management software can be developed, integrated, tested and validated.
SUMMARY OF THE INVENTION
In order to address these problems, the invention was developed which emulates optical communications hardware and interfaces with nodal control processor(s) NCP(s). This emulator may execute on a workstation platform and emulate the optical behavior as well as appropriate communications hardware functionality so that the NCP may exercise functionality in a software development, integration or validation test environment.
In other words, the invention emulates optical networking hardware functionality to allow various levels of software application unit development, test and integration test without dependency on hardware availability.
The emulator is designed to execute in multiple modes to satisfy various diverse us
Gaskin James C.
Peters-Rodbell Michael B.
Wensink James B.
Cammarata Michael R.
Ciena Corporation
Phan Thai
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