WANTED: COST-EFFICIENT, SCALABLE SOLUTIONS FOR THE OPERATOR ACCESS NETWORK

If you are a mobile or fixed network provider or offer cable TV services, you are probably facing a situation similar to most operators across the globe. Continuous increases in demand for home connectivity solutions, enterprise access, mobile backhauling and cable TV operations are driving an even greater demand for enhanced broadband communications capacity.

Traditionally, access solutions for each type of service – fixed, mobile and media – were established using proprietary protocols and requiring operators to roll out dedicated hardware solutions for each type of access solution. Today, all types of access networks are quickly converging to one common standard, Ethernet. This opens up, new opportunities for more efficient backhauling of all traffic to the metro and regional network in the same, standardized manner using fiber optics and WDM technologies.

Are hybrid optical access networks up to the challenge?

Standardization lays the foundation for solutions that are easier to manage and, most importantly, more cost-efficient to implement. As more and more service providers are opting for an architecture with network aggregation points closer to the end-user, more devices are required, and as a result the cost factor increases in importance.

Creating access networks based on passive optical technologies with easily pluggable transceivers and multiplexers has been considered the optimal solution, truly addressing this cost aspect. However, increasing needs to support more bandwidth, higher speeds and longer distances, along with the drive to establish one common infrastructure supporting multiple wavelengths, reveal the limits of passive networking.

As a result, many service providers have turned to hybrid active/passive DWDM solutions to meet optical reach requirements. Given the expectations for reduced overall cost, passive solutions are typically deployed in the network aggregation points closest to the consumer while active, monitored solutions are preferred higher up in the core network.

The challenge of amplification in hybrid networks

Although it seemed a promising solution, creating hybrid networks with traditional passive and active components presents new challenges. For longer distances, spanning from the local aggregation point to the core network through a chain of passive filters, the optical signals will likely need to be amplified to reach from the starting point to the end. Due to the nature of passive solutions not supporting smart amplification and spectral equalization, the amplification is usually handled further up in the network architecture, in an active site.

As passive multiplexers and filters are deployed in a chain, at various distances from the active node, the signal strength will most likely also vary for different sets of wavelengths originating from different multiplexers. The problem arises when all signals across the band are amplified proportionally, introducing the risk that stronger noise becomes dominant over weaker signals. To avoid this, each channel typically must be mastered and balanced manually to ensure optimal throughput of the signal. The big question this raises is: How do we prevent management of a traditional hybrid passive/active solution in this manner from becoming a total nightmare for the operator networking department, soaking up costs and manhours?

Hybrid access networks the Smartoptics way

To help operators meet the increased traffic requirements and grasp the full benefit of optical communication across the access network, we have set out to identify a new, smarter way to combine passive and active WDM technologies. At Smartoptics, we are confident that the answer to this challenge, as well as many others, lies in an open approach to optical networks. Our interpretation of open-line networking is centered around solutions where pluggable DWDM transceivers can be embedded in standard switches and where the where the optical channels are routed by an open line system.

In light of our commitment to open optical networking, we have recently launched a new versatile family of open line system components named DCP-F. The family has been designed to meet the flexibility demands in relation to configuring optical point-to-point, ring, and mesh topologies at the lowest possible cost while still supporting new high-speed, low-cost DWDM modulation formats, such as 400ZR. With fully automated balancing of wavelengths, you'll be able to sleep soundly without headaches and bottlenecks involving needs for addressing different levels of amplification for different nodes in the network. Overall, the DCP-F family is engineered to leverage all the optical capacity available in the network in order to ensure optimal performance of the optical links in hybrid passive/active networks and create a redundant, scalable and future-proof solution.