Huawei - 40G

OTN (Optical Transport Network) :- An Optical Transport Network (OTN) is composed of a set of Optical Network Elements connected by optical fiber links, able to provide functionality of transport, multiplexing, routing, management, supervision and survivability of client signals. Benefits over SDH and SONET : Ultra capacity with high accuracy, Terabit/second per fibre via DWDM lines Service transparency for client signals Asynchronous mapping, powerful FEC function, predigest network design and reduce the cost Compared with traditional WDM : Enhanced OAM & networking functionality for all services Dynamically electrical/optical layer grooming OTN Network layers & interface structure: The optical transport module-n (OTM-n) is the information structure used to support OTN interfaces.

As shown in the figure above, the OTM-n.m (n 1) is composed of OTSn, OMSn, OCh, OTUk/OTUkV, and ODUk. n indicates the number of the maximum wavelength supported by the interface in case of the minimum bit rate supported by the wavelength. When n is 0, it indicates one wavelength.m indicates the bit rate or bit rate set supported by the interface.r indicates the reduced function. OTM-0.m need not label r, because one wavelength indicates the reduced function. OTM-nr.m and OTM-0.m is composed of OPSn, OChr, OTUk/OTUkV, and ODUk. The information structure that supports the OTN interface is called OTM-n, that is, the optical transport module-n. The OTM-n includes two structures: OTM with full functionality OTM-n.m, OTM with reduced functionality OTM-0.m and OTM-nr.m.

OPUk: Optical channel Payload Unit-k ODUk: Optical channel Data Unit-k OTUk: completely standardized Optical channel Transport Unit-k OTUkV: functionally standardized Optical channel Transport Unit-k OCh: Optical Channel with full functionality OChr: Optical Channel with reduced functionality OMS: Optical Multiplex Section OTS: Optical Transmission Section OPS: Optical Physical Section OTM: Optical Transport Module

n represents the maximum number of wavelengths that can be supported at the lowest bit rate supported on the wavelength, m=1,2,3,12,23,123 OTS_OH, OMS_OH, OCh_OH and COMMS OH information fields are contained within the OOS OSCOptical Supervisory Channel used to transmit OOS The figure on shows the composition of the OTM-n.m signals of the OTM interface with complete function. The OTM-n.m is composed of up to n multiplexing wavelengths and OTM overhead signals that support the non-associated overhead, m can be 1, 2, 3, 12, 23, or 123.m=1 indicates the signals are OTU1/OTU1V. m=2: indicate the signals are OTU2/OTU2V. m=3 indicates the signals are OTU3/OTU3V. m=12 indicates partial signals are OTU1/OTU1V and partial signals are OTU2/OTU2V. m=23 indicates partial signals are OTU 2/OTU2V and partial signals are OTU3/OTU3V. m=123 indicates partial signals are OTU 1/OTU1V, partial signals are OTU2/OTU2V, and partial signals are OTU3/OTU3V. The physical optical feature specifications of OTM-n.m signals are determined by the suppliers. The recommendations do not have specific specifications. The optical layer signal OCh is composed of OCh payload and OCh overhead. After the OCh is modulated to the OCC, multiple OCC time division multiplexes (TDM) constitute the OCG-n.m unit. OMSn payload and OMSn overhead constitute the OMU-n.m. OTSn payload and OTSn overhead constitute the OTM-n.m unit. The overhead and generic management information of the optical layer units constitute the OTM overhead signal (OOS), which is transmitted by 1-channel independent OSC in the non-associated overhead. The overhead of electrical layer units such as OPUk, ODUk, and OTUk are the associated channel overheads, which are transmitted together with the payload.

OTN Interface Structure: Reduced Functionality

Mapping & Multiplexing:

OTUk -> OTMOTU1[v]

OTU2[v]

OTU3[v]

OTU4[v]

Optical-Layer Overheads :

TTI: Trail trace identifier BDI-O: Backward defect indication overhead BDI-P: Backward defect indication payload PMI-P: Payload missing indicationFDI-O: Frontward defection indication overheadFDI-P: Frontward defection indication payloadOCI: Open connection indication

The OMS overhead is used to support the maintenance and operation function of the optical MS, and is terminated at the OMU signal assembly and dissemble places, including:FDI-P: Transmit OMSn payload signal status to the downstream direction.FDI-O: Transmit OMSn overhead signal status to the downstream direction.BDI-P: Transmit the OMSn payload signal invalidity status detected from the OMSn terminal sink function to the upstream.BDI-O: Transmit the OMSn overhead signal invalidity status detected from the OMSn terminal sink function to the upstream.PMI: Transmit the information with a OCCp containing optical channel signal information at the upstream of OMS signal source terminal to the downstream, to suppress subsequent reporting of signal invalidity status.The OCh overhead is used to support the maintenance function of the fault management in the optical channel, and is terminated at the OCh signal assembly and dissemble places, including:FDI-P: Transmit OCh payload signal status to the downstream direction.FDI-O: Transmit OCh overhead signal status to the downstream direction.OCI: It is the OCh open connection indication. The OCI is the signal sent to the downstream. It indicates that the matrix connection is opened when the upstream delivers the management commands in the connection function. Then, at the OCh terminal point, detect that the OCh signal loss status may be related to the open matrix.

Hardware Description: There are three types of network element that are being used in Bharti 40G Expressway network . OSN 3800 OSN 8800 T32 for OPTICAL OSN 8800 T64 for Electrical

OSN 3800 : (OLA /ILA)

Major card that are being used in Bharti Expressway Network.1- OAU1 (Optical Amplifier Unit )2- ST2 (optical supervisory channel board)3- PIU (Power Interface Unit)4- AUX (System Auxiliary Interface Board )5- FAN (FAN Unit)6- SCC (System Control & Communication Unit)7- DFIU (Bidirectional Fiber Line Interface Unit)

Slot assignment :

U2000 View :

OAU1 : (optical Amplifier Unit ) : Type description of the OAU1 board Basic function of OAU : Amplifies the input optical signals in C band. The totalwavelengths range from 1529 nm to 1561 nm. Supports the system to transmit services over different fiber spanswithout electrical regeneration.

Gain Adjustment : The OAU100 continuously adjusts the gain from 16 dB to 25.5 dBbased on the input optical power. The OAU101/OAU102 continuously adjusts the gain from 20 dB to31 dB based on the input optical power. The OAU103 continuously adjusts the gain from 24 dB to 36 dB basedon the input optical power. The OAU105 continuously adjusts the gain from 23 dB to 34 dB basedon the input optical power. The OAU106 continuously adjusts the gain from 16 dB to 23 dB basedon the input optical power.

Online optical performance monitoring: Provides an in-service monitoring port (MON). This port connects to an optical spectrum analyzer or spectrum analyzer unit to monitor the spectrum and optical performance of the multiplexed signal without affecting traffic.

OSN 8800 T32 (Optical)