A Guide to Retiring SDH & TDM Networks
The telecommunications industry is witnessing a significant transformation as operators realize the urgent need to retire their legacy Synchronous Digital Hierarchy (SDH) and TDM networks. With the advances of packet networks, this migration is not just a necessary transition but a strategic opportunity to enhance service offerings and operational efficiencies.
Service providers already have established packet networks to support IP and Ethernet services. However, most of these Service Providers are also running a TDM network in parallel to the packet network. This legacy TDM network enables them to continue to support customers with high-value legacy SDH services such as private line services or support legacy infrastructure like voice trunking.
For the reasons given below Service Providers now have an urgent need to migrate these services onto the packet network. This packet network must support the full range of services they currently support on the SDH network and the network must offer equivalent, or better, performance than the existing SDH network. The migration itself should be “invisible” to the end users, with no service disruption.
Why Migrate from TDM Services?
The truth is for many years there was no need to do this. In most cases, network operators built a new packet network to support these new IP and Ethernet services. The SDH network continued to support the circuit switched services, as it remained highly reliable and continued to meet all of the customer expectations.
We see a number of factors that have now changed; this is forcing Service Providers to migrate their SDH services away from their legacy SDH networks.
SDH vs Packet Networks: What is the Difference?
The SDH architecture, originally designed for circuit-switched services, lacks the flexibility needed for modern, data-intensive applications. With the rise of 5G, fiber-to-the-premise (FTTP), and IoT applications, there is a pressing need for networks that can support a myriad of IP-based services.
Maintaining legacy SDH networks has become increasingly expensive. Operators face rising maintenance costs, resource drain, and a loss of skilled personnel familiar with SDH technologies. This trend is compounded by the fact that many service providers have ceased offering new SDH-based services. Regulatory pressures are pushing industries to improve their carbon footprints.
Transitioning to advanced packet networks presents opportunities for significant reductions in power consumption and cooling requirements. Legacy SDH systems often lack the robust security features necessary to combat modern cyber threats. As strategic industries and service providers converge their IT and operational technologies, implementing advanced security protocols becomes paramount to safeguarding critical infrastructure against evolving threats.
What are the downsides of maintaining SDH services?
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End of life and support for legacy SDH technology: Many SDH systems are reaching the end of their operational lifespan, with equipment often over 20 years old. As these systems age, the risk of outages increases, and sourcing spare parts becomes increasingly challenging due to the shutdown of vendors and component suppliers.
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Cost Inefficiencies: Maintaining legacy SDH networks has become increasingly expensive. Operators face rising maintenance costs, resource drain, and a loss of skilled personnel familiar with SDH technologies. This trend is compounded by the fact that many service providers have ceased offering new SDH-based services.
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Need for Modernization: The rapid evolution towards 5G, Gigabit Fiber to the Premise (FTTP), and a digitized cloud economy necessitates a shift to IP-based transport. Newer applications and devices predominantly rely on IP protocols, necessitating an infrastructure that can efficiently support these services.
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Environmental Considerations: Regulatory pressures are pushing industries to improve their carbon footprints. Transitioning to advanced packet networks presents opportunities for significant reductions in power consumption and cooling requirements.
SDH to Packet Migration is an Opportunity
The migration from SDH to advanced packet networks represents a pivotal moment for telecommunications operators. While the challenges of transitioning from legacy systems are significant, the potential benefits—including enhanced service capabilities, increased revenue opportunities, and improved operational efficiencies—are compelling. By adopting a strategic approach to migration, investing in workforce development, and prioritizing security, operators can position themselves for success in the evolving digital landscape. The time has come to turn the lights out on SDH and embrace the opportunities presented by modern packet networks.
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