The difference between DWDM and OTNDefinition: Dense Wavelength Division Multiplexing (DWDM) is an optical multiplexing technology used to increase bandwidth over existing fiber networks. DWDM works by combining and transmitting multiple signals simultaneously at different wavelengths on the same fiber. The technology creates multiple virtual fibers, thus multiplying the capacity of the physical medium. ITU-T defines an Optical Transport Network (OTN) as a set of Optical Network Elements (ONE) connected by optical fiber links, able to provide functionality of transport, multiplexing, switching, management, supervision and survivability of optical channels carrying client signals. Difference between DWDM and OTN OTN optical transport networks are actually DWDM (dense wavelength division multiplexing) and ASON (Automatic Switched Optical Networks). First Huawei Transmission OTN with optical crossability, namely, by loading the WSS ROADM module, MESH network structure can make its composition is similar to that of the ASON equipment, improve the service scheduling flexibility, and increased network security; secondly, OTN electrical crossability, namely each channel sub rate crossability, this part and SDH the effects are similar, but the OTN frame has its own special structure, that is the 2.5G ODU1 particles and 10G particles of ODU2, there are also special for data service of ODU1E and ODU2E.+. Each of the DWDM channels is divided Bohebo and different function plates are required with pigtail connection, OTN can now be configured This level adds optical path-level monitoring. It performs similar functions to the ‘Line Overhead’ in SONET/SDH. which allows viewers better to know more about the DWDM and OTN. How does G. alarm indication signals and automatic protection switching. ODU: Optical Data Unit. and a header describing the type of that data. The transport network provides paths to the service network. There are six distinct layers to this format. omitting the pigtail connection. . as so the service network can be seen as a client of the transport network.709 OTN defines a frame format that "wraps" data packets. we will briefly introduce the role of OTN and its work principle. Increasing the cross function. The Role of OTN Telecommunication networks can be divided into two networks: service network and transport network. many people are confused about the functions of DWDM and what is OTN really used for. It is analogous to the ‘Path’ layer in SONET/SDH. into port. Besides introducing the difference between DWDM and OTN. OPU: Optical Channel Payload Unit. don't use so much pigtail connection. G. more flexible and less fault point is more easily maintained. This contains the encapsulated client data.709 OTN work? At a basic level. in order to solve these problems. in a format quite similar to that of a SONET frame. it is actually more technically difficult. This loss is dependent upon the number of channels but can be mitigated with optical amplifiers. OMS: Optical Multiplex Section. This deals with fixed wavelength DWDM (Dense Wavelength Division Multiplexing) between OADMs (Optical Add Drop Multiplexer). Although this task would appear to be simply the opposite of combining the signals. and adds performance monitoring (for the optical layer) and the FEC (Forward Error Correction). It is similar to the ‘Section Overhead’ in SONET/SDH. These effects can be minimized by controlling variables such as channel spacings. OTS: Optical Transport Section. Functions of DWDM The system performs the following main functions: Generating the signal—The source. wavelength tolerance. and laser power levels. which boost all the wavelengths at once without electrical conversion. This represents a physical optical port (such as OTU2. modulated as an analog signal.the signal may need to be optically amplified. OTU: Optical Transport Unit. Over a transmission link. Combining the signals—Modern DWDM systems employ multiplexers to combine the signals. Separating the received signals—At the receiving end. This deals with fixed wavelength DWDM between relays. Transmitting the signals—The effects of crosstalk and optical signal degradation or loss must be reckoned with in fiber optic transmission. OCh: Optical Channel. must provide stable light within a specific. Receiving the signals—The demultiplexed signal is received by a photodetector. a solid-state laser. . 10Gbps). This represents an end-to-end optical path.narrow bandwidth that carries the digital data. There is some inherent loss associated with multiplexing and demultiplexing. the multiplexed signals must be separated out. . it is certainly a significant evolutionary step in transport technology. On the DWDM side are interfaces to the optical fiber that links DWDM systems Conclusion While OTN has clearly taken many elements from previous network technology such as PDH and SONET/SDH. Service providers around the world have committed to OTN as their transport technology of choice and there are much time and energy being spent on developing new equipment to enable a greatly expanded rollout of OTN into the Service Provider networks. a DWDM system must also be equipped with client -side interfaces to receive the input signal. This function is performed by transponders.In addition to these functions.