Principal Network Architect, Backbone Network

About the role

Firmus Technologies Firmus Technologies is a global leader pioneering the development and operation of efficient AI infrastructure across Asia Pacific. Founded in Australia in 2019, our mission is to create the most efficient AI infrastructure by combining cutting-edge technology with a steadfast commitment to sustainability. At Firmus, we are unique in our approach. We design, build, and operate a new class of digital infrastructure – the AI Factory. Through our model-to-grid technology approach, we have pushed the boundaries of multi-generational liquid cooling systems, energy management, AI software orchestration, and construction. For our customers Firmus AI Cloud Our large-scale GPU cloud platform, Firmus AI Cloud, is purpose-built to deliver energy-efficient AI compute at scale to customers. It empowers developers, enterprises, educational institutions, and government users to train and deploy AI models with unmatched efficiency and cost savings. With an ever-growing suite of services and applications, we are committed to delivering a cloud experience that is market-leading, proprietary, and built to scale. Role Summary As Principal Network Architect, Backbone Connectivity at Firmus, you will lead the architecture and technical assurance of the backbone connectivity platform that underpins the Firmus AI Factory ecosystem and Firmus AI Cloud. The role directly reports to the Network Engineering team as a principal technical lead and acts as a dedicated support of the Head of Connectivity as the primary technical authority for backbone architecture. You will translate Firmus’s connectivity strategy into a scalable, resilient and vendor-neutral architecture, define the standards and design patterns that guide implementation, and ensure the backbone network positions Firmus as a leader in AI-ready connectivity, with focus on building and evolving Firmus’s national and international backbone across terrestrial and subsea networks, optical transport, IP backbone, data-centre interconnection and partner connectivity. The role directly reports to the Network Engineering team as a principal technical lead and acts as a dedicated support the Head of Connectivity as the primary technical authority for backbone architecture. You will translate Firmus’s connectivity strategy into a scalable, resilient and vendor-neutral architecture, define the standards and design patterns that guide implementation, and ensure the backbone network positions Firmus as a leader in AI-ready connectivity. This role is responsible for the technical integrity of the backbone architecture across the full lifecycle, from concept and design assurance through delivery readiness, operational resilience and continuous improvement. You will work across carriers, subsea operators, terrestrial fibre providers, data-centre partners and internal engineering teams to ensure Firmus’s network connectivity is high-performance, secure, operationally robust and ready to scale with the company’s AI infrastructure growth. Key Responsibilities As Principal Network Architect, Backbone Connectivity, you will own the technical architecture of Firmus's backbone network and act as the principal technical adviser to the Head of Connectivity, while operating as a senior technical lead within the Network Engineering team. You will convert the Firmus Connectivity Strategy into an integrated, executable backbone architecture spanning subsea and terrestrial fibre, optical transport (DWDM/OTN), IP/MPLS and segment routing, data-centre interconnection and partner connectivity. You will define the reference architecture, standards and reusable design patterns that guide engineers and partners, ensuring every AI Factory and Firmus AI Cloud service attaches through resilient, diverse and scalable backbone nodes free of unmanaged common-mode failure. Working across carriers, subsea operators, terrestrial fibre providers and data-centre partners, you will set minimum resilience profiles, validate physical-route and shared-risk-link-group diversity, and provide independent technical assurance that designs can be delivered, operated and scaled safely across their full lifecycle. You will act as technical design authority in vendor and technology selection for backbone and subsea services, lead complex backbone changes and cutovers, mentor the engineering team, and benchmark Firmus's designs against leading global operators and hyperscalers — keeping Firmus at the forefront of AI-ready network connectivity. What you’ll bring You are, first and foremost, an accomplished network architect for large-scale, mission-critical connectivity infrastructure. You bring deep expertise in national and international backbone design across terrestrial long-haul fibre and subsea systems, including landing-station connectivity, cable-landing diversity, and terrestrial route and duct engineering. You are fluent in optical transport (DWDM/OTN, coherent and client-side optics, ROADM and amplification/regeneration planning) and in IP backbone design, including IP/MPLS, segment routing, EVPN, traffic engineering, peering, transit and internet exchange, and high-capacity data-centre and customer interconnection. You understand how to design resilient, diverse networks free of unmanaged common-mode failure, using SRLG analysis, engineered failure-state capacity and physical-route evidence to prove your claims rather than assert them. Across the delivery lifecycle, you are equally at home leading architecture and design reviews, carrier and technology-vendor governance, technical evaluation of backbone and subsea services, change control, cutover planning, and operational-readiness and handover to network operations. You have authored or materially shaped reference architectures, design standards, reusable patterns and architecture decision records at a hyperscale operator, carrier, or equivalent, and you know how to keep an architecture modular and vendor-neutral so the business can flex across managed services, wavelengths, dark fibre and subsea assets as demand and economics change. You are comfortable engaging carriers, subsea consortia, internet exchanges and major equipment vendors, and you can drive value engineering and sustainability outcomes without compromising resilience or performance. Above all, you have the temperament of a senior technical leader operating across geographies: strong systems thinking, calm judgement under delivery and incident pressure, the confidence to challenge design and vendor assumptions constructively, and the communication skill to carry a room of network engineers, a customer technical review, and an executive readout with equal clarity. You bring commercial awareness, comfort operating across cultures and time zones, and a genuine passion for building AI-ready network connectivity that performs reliably from day one and positions Firmus as a leader in the field. Skills & Experience The ideal candidate will bring a strong technical foundation in network and connectivity engineering, ideally with a Bachelor's or Master's degree in Electrical/Electronic Engineering, Telecommunications, Computer Science or a related discipline, together with more than 12 years of progressive experience designing and operating large-scale backbone networks across carrier, hyperscale, cloud or specialist AI infrastructure environments. They will have deep, hands-on expertise as a principal-level network architect or distinguished engineer on national and international backbone programmes, and a proven track record owning reference architectures, design standards and technical assurance across a portfolio of concurrent connectivity initiatives. This experience should include end-to-end design and delivery across terrestrial long-haul fibre and subsea cable systems — including landing-station connectivity, route and duct diversity, and SRLG-based resilience modelling — alongside deep expertise in optical transport (DWDM/OTN, coherent optics, 100G/400G/800G) and IP backbone design (IP/MPLS, segment routing, EVPN, traffic engineering, peering, transit and internet exchange). They will have led technical evaluations of carriers, subsea operators and equipment vendors, defined the technical sections of RFPs and evaluation criteria, and worked effectively across the design-to-operate interface with Network Engineering, Data Centre and Operations teams. Experience authoring or contributing materially to global backbone reference architecture, minimum standards or interconnection strategy at a hyperscale, carrier or AI infrastructure operator is a strong differentiator, as is experience delivering into APAC markets — particularly Indonesia, Australia and Singapore — under diverse regulatory, licensing and provider conditions. Above all, the successful candidate will combine hands-on architectural depth with the influence and communication skills to lead as a senior technical authority Location & Reporting - This role is based in Sydney, Australia. - Reporting to Senior Manager, Networking Employment Basis Full-time Diversity At Firmus, we are committed to building a diverse and inclusive workplace. We encourage applications from candidates of all backgrounds who are passionate about creating a more sustainable future through innovative engineering solutions. Join us in our mission to revolutionize the AI industry through sustainable practices and cutting-edge engineering. Apply now to be part of shaping the future of sustainable AI infrastructure.