Softswitch: Controlling SIP Traffic, LCR, and Profitability

Managing voice traffic in telecom networks today requires operators to possess not only technical expertise but also the ability to effectively counter threats and optimize costs. The increase in SIP traffic volumes, the proliferation of fraudulent schemes, and the need to adhere to new authentication standards necessitate a centralized approach to controlling call routing and billing.

Risks in Modern SIP Traffic: Fraud and Outdated Protocols

The telecom industry faces a significant level of fraud. According to the CFCA Global Fraud Loss Survey 2025, global losses from telecom fraud reached approximately $41.82 billion last year. This encompasses various schemes, from international refiling to Caller ID spoofing, which directly impact operator profitability and reputation.

Furthermore, the exploitation of outdated signaling protocols remains a substantial risk. The ENISA Threat Landscape 2025 report indicates that SS7 and Diameter protocols continue to be vulnerable points for mobile networks. Despite their gradual replacement, these protocols are still used in many networks, creating conditions for unauthorized access, traffic interception, and fraudulent calls. Operators need to implement solutions that allow for traffic control and protection regardless of the underlying signaling protocol, ensuring a transition to secure IP-based systems.

Softswitch as a Control Center: Managing LCR and Profitability

A softswitch is a central component of telecom infrastructure, enabling operators to centrally manage voice traffic, perform call routing, and oversee billing processes. Its role extends beyond simple switching, encompassing functions such as Least Cost Routing (LCR) and profitability management.

LCR allows for the automatic selection of the cheapest route for each call by analyzing tariffs from various transit providers in real-time. This not only reduces operational costs but also allows the operator to dynamically respond to changing market conditions and offer competitive rates to their customers. A modern softswitch integrates with billing systems, enabling accurate calculation of the cost of each call and the setting of optimal prices for end-users, thereby maximizing profit.

In addition to LCR, a softswitch provides advanced capabilities for traffic monitoring and analysis. Detailed Call Detail Records (CDRs) offer complete information about each call: duration, destination, cost, and the route used. This data is the basis for identifying anomalies, combating fraud, and accurately calculating profitability across different destinations and services.

DooxSwitch Platform: A Comprehensive Solution for SIP Routing Optimization

The DooxSwitch Platform (DooxSwitch VoIP platform for softswitch, SIP routing, billing, and LCR) is an example of a softswitch solution designed to meet the needs of telecommunications operators in controlling SIP traffic, optimizing LCR, and increasing profitability. The platform provides tools for flexible routing management, allowing the configuration of complex routing rules based on various parameters such as number prefix, time of day, channel load, and cost.

Key functionalities of the DooxSwitch Platform in the context of LCR routing and billing include:

• Dynamic Tariff Management: Automatic updates of tariff plans from various providers and their application for LCR calculations.
• Multi-level Routing: The ability to create complex routing rules considering priorities, channel quality, and cost.
• Advanced Real-time Billing: Accurate calculation of call costs, generation of detailed CDRs, and integration with the operator’s existing billing systems.
• Monitoring and Analytics: Tools for traffic visualization, anomaly detection, and route performance analysis.
• Fraud Protection: Built-in mechanisms for detecting and blocking fraudulent calls, helping to minimize financial losses.

Utilizing the DooxSwitch Platform allows operators not only to reduce operational costs through route optimization but also to enhance billing transparency, which is critical for managing voice service profitability.

Common Mistake: Ignoring Caller ID Authentication and Its Consequences

One of the most common and dangerous mistakes affecting trust in voice services and paving the way for fraud is the neglect or insufficient support of Caller ID authentication standards. Caller ID spoofing is the basis for many fraudulent schemes, from phishing to robocalls.

In practice, this manifests as a lack of support for standards like STIR/SHAKEN. The FCC’s First Caller ID Authentication Report and Order describes STIR/SHAKEN as a framework for authenticating Caller ID in the IP portions of voice networks, involving a technical process of verifying and managing certificates. This standard allows for confirmation that the displayed number genuinely belongs to the calling subscriber or that the call has passed through a legitimate provider.

RFC 8224: Authenticated Identity Management in SIP details the use of the Identity header in SIP to convey cryptographically signed information about the call’s origin. Ignoring this standard or losing the Identity header at intermediate nodes (e.g., SBCs or transit providers) results in calls that could have been authenticated losing their trustworthiness. This not only creates a favorable environment for fraudsters but also degrades overall service quality, as subscribers become less likely to answer calls from unknown numbers.

Operators who do not implement STIR/SHAKEN or ensure proper transmission of the Identity header risk not only financial losses from fraud but also loss of customer trust and potential regulatory penalties.

Architectural Example: Integrating DooxSwitch into a National Operator’s Telecom Ecosystem

Let’s consider a typical scenario of integrating a softswitch solution, such as the DooxSwitch Platform, into the large telecom ecosystem of a national operator. In such an architecture, DooxSwitch acts as the central node for SIP traffic management, positioned between the Access Network and Transit Providers, and also integrates with the operator’s internal systems.

In practice, this looks like:

1. Traffic Ingestion: SIP calls from the operator’s subscribers (via IP PBXs, SIP phones, mobile apps) arrive at Session Border Controllers (SBCs), which perform SIP signaling normalization and basic protection.
2. Centralized Routing: SBCs forward calls to the DooxSwitch Platform. Here, the core routing logic takes place: the system analyzes Caller ID, destination prefix, time of day, and other parameters. Based on this data and current tariff plans from various transit providers, DooxSwitch applies LCR algorithms to select the optimal route.
3. Billing and CRM Integration: DooxSwitch generates detailed CDRs for each call. These records are transferred to the operator’s billing system for charging and invoice generation. Concurrently, data can be integrated with the CRM system for customer behavior analysis and service personalization.
4. Interaction with Transit Providers: After selecting a route, DooxSwitch establishes a connection with the corresponding transit provider, forwarding the call. This can be either a national or international SIP trunk.
5. Authentication Support: During the routing process, DooxSwitch ensures support for the Identity header per RFC 8224 and STIR/SHAKEN, verifying Caller ID authenticity and adding its own attestations (A/B/C) before passing the call onward. This helps combat number spoofing and increases trust in calls traversing the operator’s network.
6. Monitoring and Analytics: The platform provides operators with tools for real-time traffic monitoring, detection of suspicious activities, and generation of reports on route efficiency and profitability.

This architecture allows a national operator not only to optimize routing costs but also to enhance security, improve billing transparency, and effectively manage the quality of voice services.

Practical Steps to Enhance Profitability and Security

For operators aiming to strengthen control over SIP traffic, optimize LCR, and increase voice service profitability, specific practical steps are necessary:

1. Implement a Softswitch Solution: Selecting a platform that supports dynamic LCR, advanced real-time billing, and fraud protection mechanisms is a fundamental step.
2. Integrate with Billing and CRM Systems: Ensure seamless integration for accurate profitability calculation and service personalization.
3. Support Caller ID Authentication Standards: Actively implement and utilize STIR/SHAKEN and the Identity header (RFC 8224) to combat number spoofing and enhance call trust. This includes ensuring the correct transmission of this data across all network nodes.
4. Regular Traffic Monitoring and Analysis: Utilize softswitch tools for continuous tracking of traffic patterns, identification of anomalies, and potential fraud schemes.
5. Optimize Tariff Plans: Dynamically manage transit provider tariffs and integrate them into LCR algorithms for continuous identification of the most cost-effective routes.

Checklist for Assessing SIP Routing Optimization Readiness

• Is there a centralized SIP traffic monitoring system with detailed CDR analysis?
• Is dynamic LCR routing implemented, considering current tariffs from various providers?
• Is regular security auditing of SIP traffic conducted to detect fraudulent schemes (refiling, spoofing)?
• Is end-to-end transmission of the Identity header (RFC 8224) and STIR/SHAKEN attestation supported across all network nodes?
• Is the billing system integrated with LCR for accurate profitability calculation per destination?
• Are there tools for automatic updating of transit provider tariffs within the routing system?