Service providers in today's telecommunication market are faced with a challenge of providing high capacity services cost effectively with the shortest lead times. As a result, access network infrastructure must be flexible in design and support delivery of high-capacity services of Carrier Ethernet, MPLS, SONET/SDH, Storage Area Network (SAN), video and other demanding services while maintaining the most efficient manageable transport solution. The fiber capacity utilization has also become a major consideration for providers to reduce their overhead costs. This lead to an increasing use of wavelength division multiplexing (WDM) enabling 88+ channels of traffic to pass on different spectrally separated wavelengths over the same fiber infrastructure. The WDM layer enables most effective utilization of the existing fibers rather than investment in new construction of a new physical layer.
As a result of the growth trends, a new Optical Transport Network (OTN) layer evolved over WDM network 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 uplink pipe providing high bandwidth capabilities, low heat dissipation, compact rack space requirements, and 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.
MSPP enables service providers to offer customers new bundled services at the transport, switching and routing layers of the network, while also dramatically decreasing the time it takes to provision new services and improving the flexibility of adding, migrating or removing customers. These provisioning platforms allow service providers to simplify their edge networks by consolidating the number of separate boxes needed to provide intelligent optical access. Thus drastically improve the efficiency of networks for transporting multiservice traffic. The MSPP platforms also reduce the number of network management systems needed, and decrease the resources needed to install, provision and maintain the network (Network World).
Advantages of OTN layer
The reasons carriers are moving toward OTN include the following:
-
Desire to eliminate network layers in order to reduce OPEX. OTN convergence layer is a much less complex technology for transport applications than SONET/SDH. 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 OTN signal incorporates overhead optimized for efficient direct mapping for LAN and SAN signals and other lower rate client signals over carrier WDM networks.
-
One of the primary benefits of the G.709 OTN is that it provides a stronger FEC code than the one available with SONET/SDH, thus improving the optical network OSNR (Optical Signal Noise Ratio). This is especially important to allow improved bit error rate and link reliability in long distance amplified links with ROADM systems.
-
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.
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.
The diagram below demonstrates a 4 node network over WDM and OTN infrastructure which handles multiple SONET/SDH ADMs and Multiple Metro Eth/MPLS L2/L3 access platforms utilizing PacketLight's PL-2000 MSPP. The solution provides full hardware and fiber protected infrastructure and uses only 2 wavelengths for transporting 20 different services. The capacity of the solution can be easily increased by adding additional wavelengths and PL-2000 units to the existing infrastructure without affecting the operational traffic.
The OTN and WDM form a generic backbone network that is used by providers to transport and connect over a variety of vendor agnostic 3rd party platforms and protocols according to the service mix required at each location. Therefore, the service provider can evolve the type and mix of services over time without the need to change the generic optical transport layer infrastructure.
PacketLight Networks offers a suite of Leading 1U Metro CWDM/ DWDM and OTN solutions, for transport of data, voice and video applications, over dark fiber and WDM networks, featuring high quality, reliability and performance at affordable prices. Our products are distinguished with low power consumption ideal for CLE (Customer Located Equipment) allowing maximum flexibility as well as ease of maintenance and operation and providing real Pay-as-you-grow architecture. PacketLight customers are carriers, service providers, IT integrators and enterprises who are active in meeting the demands for metro Ethernet, business continuity, Triple Play solutions and enterprise data sharing applications. |
