Your Private Optical Highway (Control, Scale, Lowest Latency)
Dark Fiber gives you unlit single-mode strands between sites so you control the optics, speed, security, and upgrades.
Unlike managed services, Dark Fiber is a private optical layer you can light with the transponders and wavelengths you choose—ideal for data-center interconnect (DCI), AI/HPC fabrics, SAN replication, low-latency trading, and metro/backbone rings.
Related building blocks: 🔀 Wavelength → Wavelength Services • 💡 Lit Fiber → Lit Fiber • 🏢 Interconnect → Colocation • 🔗 Cloud On-Ramps → Direct Connect
See the catalog: 🌐 Connectivity • 🖧 Networks & Data Centers
🎯 Outcomes (Why Dark Fiber)
- Control & scale — pick optics (10/25/40/100/400/800G), modulation, FEC; upgrade without provider changes.
- Lowest predictable latency — optical path ≈ ~5 µs per km (one-way) + minimal gear overhead; you control regenerators/ROADMs.
- Deterministic security — keys, encryption, routes, and monitoring under your governance.
- Cost leverage at scale — high-throughput links amortize better on dark plant vs per-wave costs.
- Future-proof — re-use the same strands as line rates increase.
🧭 Scope (What We Deliver)
- Routes — metro ↔ metro, metro rings, regional/long-haul laterals; campus/building laterals.
- Fibers — single-mode G.652.D (common metro/long-haul) and G.655 (NZDSF) where available; pair(s) or diverse pairs.
- Hand-offs — meet-me room (MMR) panels in carrier-dense colocations; splice cases in manholes/handholes where required. → Colocation
- Commercials — IRU (20-year + O&M) or lease (1–5 years); build/make-ready if construction needed.
🧱 Technical Building Blocks (Spelled Out)
- Transponders/Muxponders — map client lanes (Ethernet/FC/IB) into line optics; aggregate 10×10G → 100G, etc.
- Optics — 10G (LR/ER/ZR), 100G (LR4/ER4), 400G-ZR/ZR+ coherent, 800G where plant supports it.
- DWDM — Mux/Demux add many colors onto a single pair; plan channel spacing (50/100 GHz).
- ROADM — Reconfigurable Optical Add/Drop for dynamic pathing; adds small but fixed latency.
- Amplification & REG — EDFAs and regenerators where spans exceed power budget; you choose locations & counts.
- Dispersion & OSNR — validate chromatic dispersion, PMD, and optical SNR for target line rates.
Want the carrier to light the optics instead? See Wavelength Services (10/100/400G waves with SLAs).
Want a managed L2 hand-off? See Lit Fiber.
🧰 Design Patterns (Pick Your Path)
A) Metro DCI (Active/Active)
- Short spans (≤ 80–120 km), no regen, coherent or LR4/ER4 where feasible; minimal latency for sync-rep or stretched clusters.
- Use road-tested channel plan, OTDR baseline, and light-level monitoring.
B) Regional Backbone (High Throughput)
- Coherent optics (100/400/800G), FEC enabled; EDFAs per span; ROADM mesh for dynamic add/drop; diversity to 2nd conduit/bridge.
- Plan for protect path or diverse pairs with automatic failover.
C) AI/HPC Fabric
- High-density lambdas for GPU pods (east-west); predictable microburst handling; ZR/ZR+ over metro; ROADMs where needed.
- Latency budget by job step; jumbo frames on client LANs; validate ECMP/leaf-spine symmetry.
D) Low-Latency Trading
- Shortest physical route (fiber maps, span count); minimal in-line gear; fixed FEC profile; physical diversity letters.
- Clocking & PTP discipline; Anycast for venue entry; BGP policy on front-doors. → BGP Management
E) 5G/Edge Backhaul
- Fronthaul/midhaul/backhaul pairs with strict jitter; ROADM rings for survivability; monitoring integrated with NOC. → NOC Services
🔒 Security & Integrity (Layer-1 to Layer-3)
- Physical plant — lock/splice case controls, route secrecy, seal records; change mgmt on handholes/MMRs.
- Encryption — Layer-1 AES-256 on the transponders (near-zero latency tax) or MACsec/IPsec overlays by policy. → Encryption
- Monitoring — continuous light-level and BER/FEC statistics; OTDR for fault isolation; alarms to SOC/NOC. → SIEM / SOAR • NOC Services
📐 SLO Guardrails (Experience You Can Measure)
| Metric | Target (Recommended) | Notes |
|---|---|---|
| One-way latency (metro) | Design ≈ ~5 µs/km + gear | Fiber route length rules all |
| Jitter (metro) | ≤ 50–150 µs (end-to-end) | Depends on regen/ROADM count |
| BER (post-FEC) | ≤ 1e-12 | Vendor/profile dependent |
| Availability | 99.9–99.99% design-dependent | Use diverse paths/protection |
| Diversity evidence | Route letters + maps | Separate laterals/bridges/MMRs |
| Acceptance | Power budget + OTDR + turn-up | Baseline stored with as-builts |
SLO breaches trigger tickets and SOAR workflows (reroute/rollback/dispatch) with evidence. → SIEM / SOAR
💵 Commercials (No Surprises)
- IRU vs Lease — IRU (capex + annual O&M) suits long-term/high-throughput; Lease (opex) for flexibility.
- Build & make-ready — laterals, permits, fiber construction where needed; timelines vary by municipality.
- Cross-connects — MMR fiber jumpers (NRC + MRC) per colo; plan for dual CCs on diverse panels. → Colocation
- Optical gear — transponders, ROADMs, EDFAs, shelves, optics; capex vs managed options; sparing strategy.
- Route diversity — second conduit/bridge/POP adds cost but cuts risk; request diversity letters.
🧪 Turn-Up & Acceptance (Field-Proven)
1) Design review — route maps, span lengths, loss budget, dispersion, regen plan.
2) MMR & LOA/CFA — order cross-connects; confirm connector types (LC/MPO), polarity, and panel IDs.
3) Baseline tests — OTDR traces w/ splice points, end-to-end loss; light-level & OSNR readings; record as-builts.
4) Service trials — bring up line optics; verify pre/post-FEC, BER, latency; document clean point.
5) Monitoring — add to NOC dashboards; thresholds & alerts; vendor escalation trees.
🧭 When to Choose Dark vs Wavelength vs Lit
| Need / Constraint | Choose |
|---|---|
| You want full control (gear, speed, security, upgrades) | Dark Fiber |
| You want SLA per-wave and managed optics | Wavelength |
| You want a managed L2 hand-off (EPL/EVPL) | Lit Fiber |
Often, customers mix: Dark for DCI/AI backbones, Wavelength for regional jumps, Lit for branch aggregation.
🔗 Interconnect & Cloud
- Colo hubs for low-latency meet-points with carriers and partners. → Colocation
- Cloud on-ramps (AWS/Azure/GCP) adjacent to your dark routes; deterministic paths to VPC/VNet workloads. → Direct Connect
- Edge delivery via CDN/WAF on Internet-facing surfaces; keep origins cloaked (allowlist + mTLS). → CDN • WAF / Bot Management
📜 Compliance Mapping (Examples)
- PCI DSS — encrypted transport (L1/MACsec/IPsec), access logs, route evidence.
- HIPAA — confidentiality/integrity of ePHI; tamper-evident change logs.
- ISO 27001 — A.13 network security, A.12 ops, A.16 incident.
- NIST 800-53/171 — SC-7/SC-12/SC-13 (boundary, crypto).
- CMMC — enclave separation; evidence of controls.
Artifacts (OTDR traces, light-levels, BER/FEC, diversity letters) stream to SIEM for audits. → SIEM / SOAR
🛠️ Implementation Blueprint (No-Surprise Rollout)
1) Route & capacity plan — spans, latency budget, diversity objectives, growth to 400/800G.
2) Contracts — IRU/lease terms, O&M, SLAs (repair intervals), diversity letters.
3) MMR interconnect — order cross-connects (dual where possible); inventory panel IDs.
4) Optical design — transponder choice, channel plan, FEC, ROADM/EDFA placements; sparing.
5) Acceptance — OTDR, loss, OSNR, BER/FEC, latency; store as-builts & baselines.
6) Monitoring & NOC — thresholds, alarms, escalation trees; monthly reports. → NOC Services
7) Security — encryption policy (L1/MACsec/IPsec), key custody, SOC alerts. → Encryption • Key Management / HSM
8) DR & runbooks — failover paths, fiber cut playbooks, vendor dispatch SLAs; test twice yearly.
🔄 Where Dark Fiber Fits (Recursive View)
1) Grammar — the physical rails of Connectivity and Networks & Data Centers.
2) Syntax — supports Cloud patterns (on-ramps, lakehouse, DCI).
3) Semantics — Cybersecurity protects meaning (L1/MACsec/IPsec, monitoring evidence).
4) Pragmatics — SolveForce AI predicts risk/capacity, detects drift, and recommends reroutes.
5) Foundation — consistent terms via Primacy of Language.
6) Map — indexed in the SolveForce Codex & Knowledge Hub.
📞 Light Up Your Own Optical Backbone
Related pages:
Wavelength Services • Lit Fiber • Colocation • Direct Connect • Connectivity • Networks & Data Centers • Cloud • Cybersecurity • NOC Services • Knowledge Hub