Industry Outlook: The Future of STP in Telecommunications

Modernizing 2G STPs: A Crucial Step for Network Evolution

yREMORA – The Next Generation of STP Solutions

The telecommunications sector undergoes rapid transformation through technological evolution. Signal Transfer Points (STPs) once managed international roaming, routed signaling traffic, supported IoT connectivity, and ensured emergency communication reliability. Today, these legacy systems present a growing challenge.

Most traditional STPs have long surpassed their intended operational lifespan, leaving operators burdened with escalating maintenance costs and mounting security vulnerabilities. Proprietary systems complicate modern infrastructure integration as vendors discontinue support. The imperative is clear: preserve the benefits of STP functionality while aligning with contemporary technological advancements.

The Ongoing Significance of the STP Function

Despite the transition to 4G and 5G, STP functionality remains essential. Legacy 2G and 3G networks continue to serve IoT applications through their extensive coverage and power efficiency. Many regions depend on older network generations for critical communications, particularly in rural areas that lack next-generation infrastructure investment.

Emergency services, international roaming, and cross-network signaling all rely on the functions that STPs provide. The technology must be modernized, but the function cannot be abandoned.
The STP function will persist in telecommunications networks until 2G and 3G completely disappear. What must change is the platform that delivers it.

Key Challenges with Legacy STPs

• Systems have outlived their intended operational lifecycle
• Vendors are ceasing support and discontinuing hardware
• Maintenance costs are escalating with proprietary hardware dependencies
• Significant security risks from outdated software and protocols
• Lack of compatibility with 5G requirements
• No support for multi-protocol communication, IP connectivity, cloud deployment, or containerization

Shifting Towards Cloud-Based STP Deployments

Cloud-native architectures present a strategic modernization opportunity. Traditional STPs rely on dedicated hardware, creating inflexibility and ongoing maintenance costs. A software-based, cloud-native approach supports virtualized environments, public and private cloud platforms, and containerized ecosystems.

yREMORA addresses this challenge with two purpose-built STP solutions:

• ySTP – Built on the YATE (Yet Another Telephony Engine) framework with integrated SCCP stack, delivering M2PA-based SS7 signaling over IP for direct Signaling End Point (SEP) connectivity. Fully API-configurable and controllable, so you can restart the node, push configuration, and query live statistics programmatically. It also provides full Global Title Translation (GTT), subsystem (SSN) management, and flexible routing and filtering (message screening) per SSN, GT, TT, TCAP application-context ID and TCAP operation code.
• oSTP – Built on the OSMOCOM STP framework with an integrated SCCP stack, delivering M3UA-based SS7 signaling with full Global Title Translation (GTT) and subsystem management

Both solutions deploy across virtualized infrastructure (VMware, KVM, OpenStack), containerized environments (Docker), or bare-metal servers, enabling operators to replace aging hardware with flexible, scalable software deployments built on proven open-source foundations.

ySTP or oSTP: Choosing the Right Variant

Both variants deliver the same STP capabilities over IP: integrated SCCP, full Global Title Translation (GTT), subsystem (SSN) management, and flexible routing and filtering, in containerized packaging with yREMORA hardening. Each carries its SS7 signaling over SCTP/IP. What differs is the open-source engine beneath, which sets the management model and tooling:

• ySTP is built on YATE, using M2PA over SCTP. It is driven through YATE’s rmanager remote console, usable locally or from another server, and is fully API-configurable and controllable (restart, configuration push, live statistics), a natural fit for automated, CI/CD-managed operations.
• oSTP is built on the OSMOCOM stack, using M3UA over SCTP. It is managed through the Osmocom VTY, a Cisco IOS-style interface that loads its configuration files at startup and offers an interactive Telnet command line for live operations, familiar to teams already running an Osmocom network.

Both run over IP with the same routing and filtering reach, so the choice comes down to the engine, console, and operational tooling that fit your team.

Comparison at a Glance

Built-in Signaling Security

A modern STP is your first line of defence at the signaling edge. Because ySTP fully decodes SCCP and reads the TCAP operation, its firewall enforces a default-deny policy: a message is dropped if it matches a block rule, exceeds a rate limit, or targets an invalid destination, and passes only when it comes from your own network or an explicitly trusted partner. The GSMA FS.11-aligned filtering (message screening) covers:

• Global-title allow/deny: whitelist trusted partner GTs, block spoofed or unallocated ranges.
• Per-operation blocking: reject operations that must never arrive from an external network (FS.11 Category 1).
• Per-operation rate limiting: cap message rates to absorb signaling floods and DoS.
• Invalid-destination filtering: drop traffic addressed to GTs that do not belong on the network.
• SMS firewall: filter SMS signaling (SRI-SM, MO/MT-ForwardSM) by application context to stop spoofing and grey-route abuse.

Deployed on the MVNO side, this protects subscribers even when the host MNO still runs unfiltered legacy equipment.

Carrier-Grade Availability and Performance

Signaling cannot go dark. yREMORA STPs use SCTP multi-homing so a link survives the loss of an IP path without resetting the association, and deploy as mated pairs so a node failure fails over in seconds instead of dropping traffic. Rolling, container-based updates keep maintenance to about a minute of controlled switchover rather than the multi-hour outages of hardware upgrades. Because throughput scales horizontally as instances are added, capacity grows with signaling demand instead of being capped by a chassis.

A Practical Migration Path

Modernization does not require a flag-day cutover. A typical yREMORA migration runs in phases, with the legacy node carrying traffic until the new one is proven:

1. Interconnect over IP – stand the STP up alongside the legacy node and bring partners onto SIGTRAN (M2PA/M3UA) while TDM still runs.
2. Bridge TDM and IP – use the STP as a signaling gateway so legacy E1/T1 and new SCTP/IP links interwork, with GTT rules mirrored on both sides.
3. Shift routing – move point-code and global-title routing to the new node, monitoring old and new in parallel.
4. Decommission – retire the legacy appliance once traffic and screening are fully validated.

Commercial Competition Analysis

Conclusion: A Call to Action for Telecom Operators

The telecom industry faces a pivotal moment where modernization represents necessity rather than option. Legacy STPs pose significant operational and security challenges within today’s competitive landscape. Cloud-native STP solutions unlock levels of efficiency, security, and adaptability that legacy systems simply cannot match.
With the signaling infrastructure market projected to grow significantly over the next decade, operators who modernize today position themselves to lead rather than follow. Even when MNOs still operate legacy STPs, a modern STP deployed on the MVNO side provides a critical layer of protection against signaling-based attacks.

Modernizing the STP is not only a cost decision but a strategic one. A software-defined signaling layer gives operators the scalability to absorb rising signaling volumes and the agility to adapt as the market shifts, turning an ageing cost centre into a competitive advantage.

yREMORA’s ySTP and oSTP provide operators with a clear modernization path: enterprise-grade SS7 routing built on open-source foundations, deployable across any infrastructure, and manageable through modern APIs. The future of telecommunications hinges on innovation. Modernize your legacy STP systems now, and dictate the change rather than follow it.