Core Network & IMS

IMS Core

Launch VoLTE, VoNR and VoWiFi fast — and retire your legacy voice core with confidence. PROTEI IMS Core is a complete, fully virtualized bundle that lets mobile operators bring HD voice to 4G, 5G and Wi-Fi, and helps fixed operators and CSPs move their voice services to an all-IP core. It brings together every IMS component defined by 3GPP — P-CSCF, S/I-CSCF, HSS, application servers, IP-SM-GW, USSI and MGW — so the full range of voice and messaging services runs on one cloud-ready platform. An optimized architecture and advanced codec support deliver crystal-clear calls, low latency and carrier-grade reliability, in full compliance with 3GPP TS 23.228, TS 23.218, TS 23.229, TS 24.229, TS 29.228, TS 29.229 and TS 29.949.

Key features:

• Cloud-ready virtualized deployment on NFV infrastructure
• From hundreds to millions of subscribers per platform, thanks to a VNF-based architecture and horizontal scalability
• Efficient scaling and traffic load balancing
• IMS elements can be enabled or disabled with zero service interruption
• Complete set of application servers for voice and messaging
• IMS ISC interfaces and iFC with third-party application support
• Standard 3GPP interfaces, procedures and reference points
• Support for non-IMS SIP devices and centralized IMS service delivery
• Flexible, pay-as-you-grow licensing

Proxy-CSCF is the secure front door of the IMS core: every signaling message to and from IMS/SIP devices passes through it. It handles device interworking, security and QoS in cooperation with the policy function, and its built-in SBC capabilities shield the network from threats, protect subscriber privacy and generate charging records. The P-CSCF routes registration and session requests to the right nodes, keeps the S-CSCF informed of the subscriber’s access network, passes session information to the PCRF and maintains a secure connection with the client device.

Interrogating-CSCF routes SIP messages to the S-CSCF assigned to each subscriber and handles requests arriving from other networks. It queries the HSS to locate the serving S-CSCF, with addresses held in DNS as A or SRV records, and — as part of the IBCF — acts as the gateway to external networks via the BGCF.

Serving-CSCF is the brain of IMS session control. At registration it downloads the subscriber profile from the HSS and uses the iFC to decide which application server handles each service request. All signaling for registered subscribers passes through it, including breakout to the PSTN, and multiple S-CSCFs are typically deployed for high availability and load balancing.

MGW (Media Gateway) performs MRF and IMS-AGW/ALG functions, interworking at the signaling level and managing media resources across gateways. An optional BGCF module provides number-based routing from the S-CSCF. PROTEI MGW supports H.248, SIP, H.323, SS7 and PRI.

Application Servers execute call-processing logic and service scenarios over SIP. PROTEI IMS bundles include TAS and SCC-AS as standard, with IP-SM-GW and USSI commonly added so SMS and USSD work natively in the IMS domain — the IP-SM-GW interworks with the legacy SMSC over MAP for seamless IMS-to-SMS delivery.

Telephony Application Server (TAS) is the key application server of the IMS core. It delivers 3GPP MMTel voice and video telephony for VoLTE, VoNR and VoWiFi subscribers, with the full set of supplementary services — call forwarding, call waiting and hold, call barring, CLIP/CLIR, and three-party and multi-party conferencing — and applies the operator’s service logic to every call. Working with the SCC-AS, it keeps calls continuous when subscribers move between IMS and circuit-switched coverage.

Session Border Controller (SBC)

Protect every IP voice border and solve SIP interoperability. PROTEI Session Border Controller combines an interconnect SBC (I-SBC) and an access SBC (A-SBC) on one platform, securing VoLTE, VoWiFi, fixed VoIP, enterprise SIP trunks and partner interconnects. It hides the network topology, normalizes SIP between vendors and shields the core against DoS and flooding, spam, brute-force attacks and toll fraud.

• Access SBC with P-CSCF functions: IPsec and TLS, SIP NAT traversal, VoLTE policy control over Rx and a WebRTC gateway
• Interconnect roles IBCF, TrGW and IMS-ALG/AGW, with SIP-I/SIP-T support and header manipulation rules
• Transcoding across G.711, G.722, AMR, AMR-WB, G.729A and Opus; SRTP encryption and T.38 fax relay
• Up to 5,000 sessions and 500 calls per second per virtual machine, and 45,000 sessions and 2,000 calls per second per N+1 cluster

Home Location Register (HLR/HSS)

One subscriber brain for 2G, 3G, 4G, 5G, IMS and IoT. PROTEI HLR/HSS is a high-performance, converged subscriber data management platform built for operators of every size. Its scalable architecture and flexible, throughput-based licensing meet today’s requirements and scale smoothly for tomorrow’s — including IoT and Private LTE/5G deployments.

• HLR and AuC for 2G/3G networks
• HSS for 4G, 5G NSA and IMS
• UDM/UDR functionality for 5G SA cores

As the master subscriber database, PROTEI HLR/HSS holds everything the network needs to serve each subscriber — identity, account status, service profile, subscribed features, preferences and current location — with a single shared database behind multiple HLR/HSS front-ends. The integrated Authentication Center (AuC) supports all major algorithms, including TUAK, Milenage and COMP128 v2/v3, and every data element and protocol is implemented in strict compliance with 3GPP standards.

The LTE-HSS profile extends the packet-switched profile with LTE subscription fields, supporting the PDN/EPS context alongside the GPRS/UMTS context so operators can provision either or both. S6a delivers seamless LTE integration, while Sh and Cx serve IMS subscribers — fully compliant with 3GPP TS 29.272, TS 29.273 and related specifications. A convenient provisioning interface ensures smooth integration with the operator’s BSS and effortless day-to-day subscriber management.

DRA/DEA

Tame Diameter complexity as your LTE, IMS and roaming traffic grows. PROTEI Diameter Routing Agent (DRA) provides a single connection point for every Diameter entity in the network. By centralizing routing, traffic management and load balancing, it lets LTE and IMS networks scale incrementally with demand while cutting the cost of connecting, provisioning and interworking Diameter equipment.

PROTEI DRA manages in-network and outbound roaming, mediates Diameter messages and strengthens signaling performance and security, while DEA functionality proxies traffic from external networks. Diameter dialect adaptation connects otherwise incompatible multi-vendor “Diameter islands”, and the platform can be deployed as an IETF Diameter Agent or a 3GPP DRA.

Typical use cases include:

• Centralized Diameter routing in LTE networks
• LTE roaming and LTE-to-2G/3G roaming
• Centralized charging
• HSS address resolution and PCRF binding

The result: a leaner LTE core and a single, secure interconnect point to other networks.

Signaling Firewall

Close the door on SS7, Diameter and GTP attacks before they cost you revenue or reputation. PROTEI Signaling Firewall detects and blocks irregular or malicious SS7, Diameter and GTP traffic. Built in line with GSMA security guidelines FS.11, FS.07, FS.19, FS.20, IR.70 and IR.71, it protects the network and its subscribers against fraud and prevents revenue leakage.

Multiple protection levels — monitoring and alerting, basic policing and advanced policing rules — stop network- and subscriber-targeted attacks such as spamming, flooding, fraud, location tracking, identity theft, denial of service and unlawful interception.

GTP Firewall. Data roaming brings its own risks. Following GSMA FS.20 (GPRS Tunnelling Protocol security), the GTP Firewall inspects GTP-C signaling exchanged with roaming partners over GRX/IPX on the Gp and S8 interfaces, validating messages against the subscriber’s real location and roaming status. It blocks attacks such as subscriber denial of service, session hijacking, data fraud and information disclosure, protecting both the packet core and its subscribers.

Routing and policies can be tuned individually for each SS7, Diameter or GTP connection using a wide range of filtering criteria. A modular design, built from identical connection units, makes the platform easy to expand and upgrade, with throughput of thousands of TPS per VNFC.

EIR / CEIR

Keep stolen, counterfeit and unauthorized devices off every network. PROTEI EIR checks the IMEI of every device that connects against white, gray and black lists. PROTEI CEIR runs the national program: it maintains the national lists, integrates with customs, police, the regulator and certification bodies, and synchronizes the EIR of every mobile operator automatically.

• Stolen phones stop working on every network, and the gray market shrinks
• Device registration by USSD, SMS, API or web form, with IMEI–IMSI–MSISDN binding
• Detection of cloned IMEIs, SIM boxes and every handset change, with notifications to CEIR, CRM and care systems
• MAP over the F and Gf interfaces for 2G/3G and Diameter S13 for 4G/LTE

SEPP and 5G Service Communication Proxy (SCP)

Bring signaling control to the 5G Service Based Architecture. Together with PROTEI STP and DRA/DEA, the SEPP and SCP complete the PROTEI Signaling Routing family: one secure routing layer for SS7, Diameter and 5G.

• PROTEI SEPP secures 5G roaming at the network edge over N32, with GSMA FS.36 protection such as rate limiting, anti-spoofing and discarding malformed messages, plus topology hiding and TLS
• PROTEI SCP (3GPP Release 16) routes and load-balances HTTP service requests in the 5G core, supporting deployment models C and D of TS 23.501 with NRF registration, delegated discovery and overload control
• Integrated with the PROTEI Signaling Firewall through a built-in API
• High-availability and geo-redundant configurations

Signal Transfer Point (STP)

The proven backbone of your signaling network. PROTEI STP is a high-performance platform for SS7 message routing, with highly flexible routing rules, special handling for specific message types and connections to multiple roaming providers. It is field-proven as the foundation for active steering, SMS Firewall and SS7 Firewall deployments.

PROTEI STP capabilities:

• Flexible routing on SCCP-level parameters and by TCAP operation code
• Dedicated translation types for outgoing traffic
• Flexible route redundancy
• SIGTRAN or E1/SS7 connectivity

Gateway Mobile Switching Center (GMSC)

A cost-efficient voice switch purpose-built for MVNOs. PROTEI GMSC handles voice calls for GSM/UMTS subscribers on a Class 4 softswitch, adding GMSC-specific modules such as HLR interrogation over MAP and a gsmSSF supporting CAP.

Broad signaling support ensures interoperability with MNO core networks from any vendor, with core connectivity over SIP, SIP-I, SIP-T or H.323 and PROTEI mGate media gateways for interworking with PSTN and PLMN networks. A powerful routing engine routes calls on multiple criteria such as SLA and per-direction load, while T-CSI, M-CSI and N-CSI triggering unlock the full potential of CAMEL services.