The main advantage of OTN is fully backward compatible, it can build on existing SONET / SDH management functions on the basis of not only the existence of a fully transparent communication protocol, but also for WDM-end connectivity and networking capabilities, It provides a light layer interconnect specification ROADM, and added sub-wavelength aggregation and grooming.

OTN concept covers the optical layer and electrical layer network, and its technology inherited the dual advantages of SDH and WDM, the key technical features embodied:

1. multiple client signals and transparent transmission package

Based on ITU-TG.709 OTN frame structure can support a variety of mapping and transparent transmission of client signals, such as SDH, ATM, Ethernet. For SDH and ATM standard package and can achieve transparent transmission, but for different rates of Ethernet vary. ITU-TG.sup43 to 10GE business to achieve varying degrees of transparent transmission provides additional recommendations, and for GE, 40GE, 100GE Ethernet LAN, services Fibre Channel (FC) and GPON access network business and so on, which to the OTN frame standardized mapping is currently being discussed.

2. Bandwidth large particles multiplexing, cross and configuration

Bandwidth particle layer OTN optical path is defined as data units (O-DUk, k = 0,1,2,3), i.e. ODUO (GE, 1000M / S) ODU1 (2.5Gb / s), ODU2 (10Gb / s ) and ODU3 (40Gb / s), the bandwidth particle light layer of wavelength, with respect to the SDH VC-12 scheduling particles / VC-4, the particles OTN multiplexing, cross and configuration obviously much larger, can significantly improve high Customer service adaptation bandwidth data transmission capability and efficiency.

3. Powerful overhead and maintenance management capabilities

OTN offers similar SDH overhead management capabilities, OTN frame structure, enhanced OTN optical path layer digital surveillance capability. In addition OTN also provides six levels of nesting tandem connection monitoring (TCM) function, which makes the OTN network, the take-end and performance monitoring multiple segments simultaneously way possible. The inter-carrier transmission provides a suitable management tools.

4. The enhanced networking and protection

By OTN frame structure, ODUk cross and multi-dimensional reconfigurable OADM (ROADM) introduced, greatly enhancing the networking capability of optical transport network change based SDHVC- 12 / VC-4 scheduling bandwidth and WDM Status point provide high capacity transmission bandwidth. Forward Error Correction (FEC) technology adoption, a significant increase in the distance between the optical layer transmission. In addition, OTN will provide a more flexible electrical and optical layers based service protection features such as ODUk layer of light-based subnet connection protection (SNCP) and shared ring protection, light layer of an optical channel or MSP-based, etc. But technology is not yet standardized shared ring.