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 hubsfor 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 deliveryvia 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
Key terms in plain language
Open a term for a concise explanation of language used on this page.
Fiber Internet
Internet delivered through strands of glass using light. Fiber commonly supports high capacity, low latency, and strong upload performance, but availability must be confirmed for the exact address.
Latency
The time it takes data to travel between two points. Lower latency improves voice, video meetings, cloud applications, gaming, and other real-time services.
Service-Level Agreement (SLA)
A provider’s written commitment covering service targets such as availability, response time, repair time, and sometimes financial credits when commitments are missed.
Cybersecurity
The practices and controls used to protect identities, devices, networks, applications, and data from unauthorized access, disruption, or manipulation.
Colocation
Placing customer-owned servers and network equipment in a professionally operated data center that provides power, cooling, physical security, and connectivity.
Content Delivery Network (CDN)
A distributed system that serves website or application content from locations closer to users, improving speed, resilience, and capacity.
Artificial Intelligence (AI)
Software designed to perform tasks involving prediction, classification, generation, reasoning, or decision support. Business use still requires clear data, governance, security, and human accountability.