Shared Spectrum & MOFN#

Liam Taylor - EXA Infrastructure

• Why: The gap between buying individual wavelengths (low bandwidth, high cost/Gbit) and building your own DWDM line system (high complexity, staffing, licensing) is exactly where inter-DC and long-haul capacity buyers are stuck. Spectrum products are the current answer.
• What: A taxonomy of photonic-layer sharing models with their operational trade-offs: Alien Waves (customer transponders directly on the vendor's mux — cheapest, but limited monitoring, fixed transmission modes, one cross-connect per wave), Managed Spectrum (customer-owned WSS add/drop, vendor-assigned channels — advanced monitoring, power policing, privacy, but changes need negotiation and require customer line-terminal equipment), and Unmanaged Spectrum (a spectral block assigned by the vendor, channels fully customer-managed — maximum flexibility, but demands the most expertise). Plus MOFN (Managed Optical Fiber Network): a provider-built dedicated fiber + DWDM system delivered as a managed service. Spectrum sizing depends on distance, fiber quality, ROADM count, amplification (Raman vs EDFA), and transponder generation (e.g., Nokia ICE6).
• How: The vendor assigns and polices GHz-wide spectrum blocks in its photonic layer; the customer brings transponders and manages the optical/electrical layers above them.
• Where applicable: Operators scaling WAN/inter-DC capacity without building their own line system; terrestrial and submarine (subsea may require ASE fill). Note this is an EXA Infrastructure talk and is largely a product-landscape explainer rather than a neutral engineering treatment — useful for the model taxonomy and the acceptance-criteria/change-process checklist it implies, not as vendor-independent advice.