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Optical Transport Network (OTN) Layer

The new Optical Transport Network (OTN) layer evolved over the layer-1 DWDM network for enabling more efficient convergence of traditional SONET/SDH and new data services.   The OTN layer is designed to for highly effective mapping of different protocols and rates into the same 10G or 100G uplink pipe providing high bandwidth capabilities in simpler transparent manner at  comparatively low cost. Furthermore, OTN infrastructure enables transport over longer distances with less regeneration sites by utilizing Forward Error Correction (FEC) mechanism embedded within the OTN layer. Thus, the OTN layer forms the most efficient and cost effective Multi Service Provisioning Platform (MSPP) over WDM infrastructure.


Advantages of Optical Transport Network (OTN) layer


While using OTN, layer any protocol carried over the network has the same performance monitoring  information, whether it is SONET/SDH, Ethernet or Fibre channel.  The OTN convergence layer is a much less complex technology for transport applications than SONET/SDH, which is reflected in the much simpler clocking scheme for instance. Each network layer that a carrier must manage creates a substantial amount of operating expense. In some carriers, an entire organizational units exist are dedicated to managing each network layer. Since operations constitute 30-40% of carriers’ annual expenses, they must minimize the number of different layers in their networks whenever possible.

The Optical Transport Network (OTN) layer is deterministic in the latency performance, in the service connection path as well as in the deterministic guarantee bandwidth for each of the service.
The OTN signal incorporates overhead optimized for efficient direct mapping for LAN, SONET/SDH and SAN signals and other lower rate client signals over carrier WDM networks.

The figures bellow show how the FEC layer can increase the optical network distance by improving the OSNR by 6-8dB without the need to use very expensive regenerator station as in the traditional SONET/SDH back bone networks.


The key to saving network operational costs is having effective Operation, administration, maintenance, and provisioning (OAM&P) capability built into the signal format. The OTN OAM&P overhead is built to providing remote manageability and all monitoring/transparency needed for reliable service provisioning.

Using the WDM infrastructure in combination with Optical Transport Network (OTN) layer enables the service providers to map any of the service offerings to end customer with easy upgrade path over existing fiber network. Since the OTN and WDM layers make up generic Layer-1 Transport network, different service types can coexist and share the same infrastructure transparently without influencing each other's performance. As an example, the service provider can offer any combination of the SONET/SDH services, MPLS, Metro Ethernet and storage services all on the same fiber network.

PacketLight product set enables carriers to offer high bandwidth, low latency, fully managed services with SLA and take full advantage of OTN network features while enabling monitoring and management of the fibers and protocols: PL-2000, PL-1000TN, PL-1000GM and PL-1000GT.

PacketLight OTN solutions are standards based and can interface with any standard based existing OTN network with interfaces of 10G OTU2 or 100G OTU4 of 3rd party vendor. Thus, PacketLight’s equipment can operate across existing OTN infrastructure and provide low footprint OTN CPE for delivering high bandwidth services in a cost effective manner providing end to end OTN layer from the customer premises at both ends.

For more information on PacketLight's OTN Products, click here.

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