Senior Core Network Architect

Cirrus Core Networks, Inc.; Northern (KY); Hybrid; USD 150,000 - 210,000; Full time

Job summary

Cirrus Core Networks is seeking a Senior Core Network Architect to own architecture and design of the mobile core across 2G/3G, 4G, IMS, and 5G. This role leads 5G SA planning, defines standards, and serves as the senior technical voice in vendor/customer engagements.

The role covers Roaming, interconnect, and non-3GPP access, with responsibility for capacity sizing, BOMs, and hardware validation. Remote work is available in the US or Europe, with full-time/contract status.

Qualifications

• 10+ years in mobile core network engineering with architecture/design authority experience.
• Deep architecture experience across 4G EPC and IMS including HSS, PCRF, DRA.
• Strong knowledge of 2G/3G interworking with 4G/5G and signaling protocols.

Responsibilities

• Own end-to-end core network architecture and design integration.
• Define routing and signaling strategy across SS7, Diameter, SIP.
• Design interconnect and roaming architecture with partners.
• Define high availability and geo-redundancy strategies.
• Lead migrations including VM, containerized, and cloud transitions.
• Review low-level designs and vendor solutions for architectural fit.
• Present high-level designs to customers and executives.

Skills

Mobile core network

Architecture/Design authority

Diameter/GTP/SIP signaling

VoLTE/VoWiFi knowledge

Cloud-native / VNF/CNF

Tools

COTS servers

Storage hardware

Networking hardware

Job description

Senior Core Network Architect (Design Authority)

US or Europe (Remote)

Details

Position

Senior Core Network Architect (Design Authority)

Location

Remote

Job Type

Full Time / Contract

Positions Available

One

Description

About CCN

Cirrus Core Networks is a US-based telecom core network operator and managed services provider serving MVNOs and MNOs.

Role Summary

The Senior Core Network Architect owns the architecture and technical design of CCN’s mobile core network across 2G/3G, 4G, IMS, and 5G. This role sets design standards, owns capacity sizing and hardware specification, leads 5G SA core planning, and serves as the senior technical voice in vendor and customer engagements.

• 5G SA core: AMF, SMF, UPF, UDM, UDR, AUSF, PCF, NRF, NSSF, NEF, SEPP, BSF, CHF, N3IWF
• 4G EPC: MME, SGW, PGW, HSS, PCRF, DRA/DEA
• IMS and voice: P-CSCF, I-CSCF, S-CSCF, TAS, MRF, BGCF, MGCF, VoLTE, VoWiFi
• Non-3GPP access: ePDG
• Roaming and interconnect: GTP Proxy, DEA, SEPP, IPX/GRX, Diameter–MAP interworking
• Legacy 2G/3G: HLR/AuC, MSC/VLR, SGSN, GGSN, STP, EIR, CAMEL
• Messaging and charging: SMSC, SMSF, OCS/OFCS
• Protocols: Diameter, GTP-C/GTP-U, SIP, SS7/SIGTRAN, MAP, HTTP/2-based SBI, PFCP

Key Responsibilities

• Own end-to-end core network architecture and design integration across the technology scope above.
• Define routing and signaling strategy across SS7, Diameter, SIP, and service-based interfaces.
• Design interconnect and roaming architecture, including interworking between 2G/3G, 4G, and 5G networks and partners.
• Define high availability, geo-redundancy, and failover strategy.
• Own capacity sizing for core network deployments and expansions, translating subscriber counts, transaction rates, session volumes, and throughput into compute, storage, and network requirements.
• Specify and validate COTS server, storage, and networking hardware for core deployments.
• Produce and review bills of materials.
• Evaluate vendor hardware and sizing proposals for accuracy and fit.

Deployment & Transformation

• Serve as design authority for major platform migrations, including VM, containerized, and cloud transitions.
• Define performance and scaling strategy.
• Lead architecture for next-generation core evolution, including 5G SA.
• Review and approve low-level designs produced by the operations engineering team.
• Review vendor solutions for architectural fit and align vendor architectures with CCN’s.
• Provide feature feasibility assessments and roadmap input to vendors.
• Interpret 3GPP specifications and ensure standards compliance.
• Approve architectural fit as part of vendor solution acceptance.
• Lead technical design workshops with customers.
• Produce and present high-level designs to customer engineering and executive audiences.

Qualifications

Required Qualifications

• 10+ years in mobile core network engineering, including several years in an architecture or design-authority role
• Deep architecture experience across 4G EPC and IMS, including HSS, PCRF, DRA, and packet core
• Solid understanding of legacy 2G/3G core networks (HLR, MSC/VLR, SGSN/GGSN, SS7/MAP) and how they interwork with 4G and 5G
• Strong command of Diameter, GTP, SIP, and SS7/SIGTRAN signaling
• Proven experience designing roaming and interconnect solutions, including GTP Proxy and DEA
• Proven experience sizing mobile core deployments from traffic and subscriber models through to hardware requirements
• Working familiarity with COTS server, storage, and networking hardware for core network deployments
• Experience designing for virtualized and cloud-native network functions (VNF/CNF, Kubernetes or similar)
• Strong working knowledge of 3GPP specifications
• Excellent written and verbal communication, including presenting to technical and executive audiences

Preferred Qualifications

• 5G SA core architecture experience, including service-based architecture, network slicing (NSSF), and SEPP-based roaming (strongly preferred)
• VoLTE and VoWiFi architecture experience, including ePDG
• Experience in a multi-vendor, multi-customer managed services environment
• Experience with IPX/GRX roaming hub providers

CCN offers a competitive compensation package that reflects the scope and seniority of this role, the candidate’s experience, and local market rates. Because this role is open to candidates in the US and Europe, compensation and benefits will vary by country and will be structured in line with local market practice and employment requirements. Details will be discussed with candidates during the interview process.

Cirrus Core Networks is an equal opportunity employer. We are committed to building a diverse, inclusive team and do not discriminate on the basis of race, color, religion, sex, pregnancy, sexual orientation, gender identity or expression, national origin, age, disability, genetic information, veteran status, or any other characteristic protected by applicable law in the country where the role is based. Employment decisions are based on qualifications, merit, and business needs. If you need an accommodation during the application or interview process, please contact: [e-mail].