About the Role
You will lead the design and operation of Sesterce's AI cluster network fabrics, owning InfiniBand and RoCE architectures, RDMA performance, and fabric reliability for frontier-scale training and inference workloads. You will define long-range fabric architecture, drive congestion control strategy, make topology design decisions that improve collective performance, establish observability standards, set cable plant strategy, lead vendor engagement, and mentor senior engineers while serving as the final escalation point for fabric architecture decisions.
Requirements
- Demonstrated experience in hyperscale networking, HPC fabrics, RDMA systems, or distributed systems networking at large scale (hundreds to hundreds of thousands of accelerators)
- Deep expertise in ECMP, adaptive routing, queueing theory, network telemetry pipelines, InfiniBand, and optical systems
- Proven track record designing and operating AI or HPC interconnects
- Strong working knowledge of network behavior under distributed training frameworks and collective communication libraries (NCCL, UCX)
- Experience leading major technology transitions across multiple hardware generations and mixed-vendor environments
- Ability to bring credibility with hardware vendors, datacenter teams, software platform leaders, and executive stakeholders
Responsibilities
- Define the long-range architecture for AI fabric evolution across RoCE, NVIDIA InfiniBand, Clos and spine-leaf topologies, mesh interconnects, and emerging optical fabric designs
- Lead migration from 100G to 400G, 800G, and 1.6T
- Own congestion control strategy including PFC, ECN, DCQCN, queue management, path diversity, and routing policy for high-performance collective traffic
- Drive topology design decisions that improve NCCL all-reduce performance, collective completion times, tail latency stability, and fault containment
- Establish observability standards for fabric telemetry, queue behavior, packet loss, jitter, retry behavior, and end-to-end job impact
- Set cable plant strategy across fiber topology, optics qualification, and DAC/AOC standards
- Lead vendor engagement for switches, optics, NICs, and fabric management tooling
- Define upgrade and migration playbooks
- Mentor principal and staff engineers
- Serve as the final escalation point for fabric architecture decisions