TDM to SIP Network Transformation
A proven strategy to modernize central office infrastructure with Tmedia gateways and a softswitch, minimizing subscriber disruption and operational risk.
Why Central Office Switches Need Upgrading
Thousands of central offices serving small and rural communities around the world still rely on aging TDM central office switches. These platforms are costly to operate, increasingly difficult to maintain, and many are approaching or have reached end-of-life. At the same time, service providers are investing in broadband expansion to support new, higher-value IP-delivered services.
When planning a central office switch upgrade, subscriber disruption and total cost are critical considerations. Truck rolls to install ATAs, media gateways, or replacement telephones at customer premises are expensive and operationally disruptive. CPE self-installation programs often introduce additional support challenges. From the subscriber’s perspective, service disruption increases the risk of churn to OTT providers or abandonment of the circuit altogether.
As one service provider noted: “If you must make a change to the central office switch, it is imperative that it is nearly invisible to the subscriber.”
To address these challenges, TelcoBridges, working with its alliance partner Metaswitch, developed a TDM-to-IP network transformation strategy designed to modernize central office infrastructure while minimizing subscriber disruption and operational risk.
The Network Transformation Architecture
Most existing TDM central office switches share a common architecture. Circuits from international carriers, national carriers, and interconnect partners are terminated using SS7 signaling and TDM voice equipment. Subscriber lines are connected through access equipment supporting residential, business, and enterprise-class services. At the core of the central office, the TDM switch provides intelligent call routing and the full set of Class 5 telephony features.
Figure 1: Simplified TDM Central Office Architecture
The TDM-to-IP transformation replaces the legacy TDM switch with a combination of TelcoBridges Tmedia gateways for network connectivity and a Metaswitch CFS softswitch for call routing and subscriber features. Existing subscriber loops and SS7 trunking circuits remain in place, while signaling is converted to SIP. Call control and feature logic are moved into the software domain, running on generic hardware and deployable on premises or in the cloud.
Figure 2: Transformed Central Office
As part of the transformation, the user experience of legacy TDM Class 5 features is preserved through feature emulation, ensuring a seamless transition for subscribers. Once deployed, the architecture also enables the introduction of new IP-based services, such as voicemail-to-email and subscriber self-administration, offered as value-added services or upgrades.
At a macro level, multiple central offices can be served by a consolidated and redundant Metaswitch softswitch. This model allows trunking services to be centralized in fewer locations, reducing interconnection costs and termination fees. Inter-office traffic is carried over the IP data network, eliminating the need for dedicated SS7 interconnection circuits.
Figure 3: Macro-level View with Multiple Central Offices
In addition to simplifying network architecture, transformed central offices realize significant operational savings through reduced power consumption, lower cooling requirements, and decreased maintenance overhead.
Network Transformation Benefits
Minimal Subscriber Disruption
Little or no disruption to the subscriber experience during the transition from TDM to IP.
New IP-Based Services
Opportunity to offer new high-margin IP-based services like voicemail-to-email and subscriber self-administration.
Software-Based Call Control
Centralization of call switching and features in software, running on generic hardware or in the cloud.
No Additional CPE
No customer premises equipment changes needed, resulting in fewer truck rolls and reduced deployment costs.
OPEX Model
Migration to an OPEX model for softswitch software, reducing capital expenditure requirements.
Reduced Power & Cooling
Significant reduction in power consumption and cooling requirements, with ongoing hardware and software support.
Case study
See how a telecom service provider reduced power usage, projecting to save over $2 million per year
Next Steps
Complete the form below to request a consultation with our experts who can evaluate and make recommendations on your specific situation.
By submitting this form, your information will be processed in accordance with our Privacy Policy.
Or contact [email protected]