Private WAN with QoS, Deterministic Paths & Carrier-Backed SLAs
MPLS (Multiprotocol Label Switching) delivers a private, carrier-managed WAN with Quality of Service (QoS), traffic engineering, and contracted SLAs. It’s the right tool when you need predictable latency, class-of-service guarantees, and segmented L3VPNs between sites—especially for real-time apps and regulated environments.
Where this fits in the SolveForce model:
🌐 Connectivity (Grammar) → Connectivity • 🖧 Fabric → Networks & Data Centers
☁️ Cloud (Syntax) → Cloud • 🔒 Security (Semantics) → Cybersecurity
🔀 Overlay interop → SD-WAN • SASE • Routing → BGP Management
🎯 Outcomes (What MPLS Delivers)
- Deterministic paths with carrier traffic engineering and predictable latency/jitter.
- QoS enforcement end-to-end for voice/video/transaction flows (EF/AF/BE classes).
- L3VPN segmentation between sites/business units without Internet exposure.
- Strong SLAs for availability, latency, jitter, and Mean Time To Restore (MTTR).
- Coexistence with SD-WAN/SASE for hybrid underlay architectures.
🧭 When to Choose MPLS (and When to Pair It)
Choose MPLS when you need:
- Strict QoS guarantees for real-time apps (voice trading floors, telemedicine, SCADA).
- Regulatory isolation (finance/health/public sector) without DIY encryption on every hop.
- Predictable inter-site performance with committed SLAs.
Pair with SD-WAN/SASE when you want:
- Dual-/multi-underlay resilience (MPLS + DIA + Fixed Wireless/5G) with app-aware steering. → SD-WAN
- Cloud breakout policies near SaaS/IaaS while private flows stay on MPLS. → SASE • Cloud
🧱 MPLS Service Types (Spelled Out)
- L3VPN (Layer-3 VPN) — the carrier routes IP between your sites inside private VRFs (Virtual Routing and Forwarding). Your edges run BGP/OSPF toward the provider PE; the carrier handles the core.
- VPLS (Virtual Private LAN Service) — Layer-2 “virtual switch” that extends Ethernet across sites (LAN-like behavior). → VPLS
- Pseudowires (L2VPN/VPWS) — point-to-point Ethernet circuits over MPLS when you need simple L2 adjacency.
- Traffic Engineering (TE) — carrier-side capacity planning; some providers offer RSVP-TE or Segment Routing (SR-MPLS) for explicit constraints on premium paths.
Encryption note: MPLS is private, not encrypted by default. Add IPsec/MACsec where policy demands. → Encryption
🎛️ QoS & Classes of Service (CoS)
Typical CoS tiers (provider-specific names vary):
| Class (example) | Intended Traffic | Markings (example) | Notes |
|---|---|---|---|
| EF (Expedited Forwarding) | Voice/telepresence | DSCP EF (46), 802.1p 5 | Strict priority, low-latency queue |
| AF (Assured Forwarding) | Interactive apps (Citrix/EMR, control) | DSCP AF2x/AF3x | Bandwidth guarantees, low drop |
| BE (Best Effort) | Bulk/file/backup | DSCP 0, scavenger as needed | No guarantees |
Best practice:
- Classify/mark at the edge (trusted boundary), honor at WAN egress.
- Police scavenger/bulk classes; protect EF from starvation with precise shaping.
- Validate CoS with synthetics per class; publish per-class SLOs.
📐 SLO Guardrails (Recommended Targets)
| Metric | Metro (Class A) | Regional (Class B) | Notes |
|---|---|---|---|
| One-way Latency | ≤ 2–5 ms | 15–35 ms | Per route class (95th percentile) |
| Jitter | ≤ 15% latency | ≤ 15% | EF must remain tight for voice |
| Packet Loss | < 0.1% | < 0.1% | Per class; watch EF drops |
| Availability | 99.95–99.99% | 99.9–99.95% | Depends on design/protection |
| MTTR | ≤ 4 hours | ≤ 4–8 hours | Confirm provider SLA clauses |
We enforce SLOs via continuous synthetics/telemetry and open carrier tickets on breach. → NOC Services • Circuit Monitoring
🔗 Edge & Routing Patterns
- PE–CE Routing: eBGP preferred (policy clarity, fast withdraws); OSPF as alternative where required.
- VRF Design: isolate business units/crown-jewel apps; route-leaking only where justified.
- Anycast Front Doors: publish identical VIPs from multiple hubs; withdraw on health. → BGP Management
- Hybrid Underlay: MPLS + Fiber DIA + Fixed Wireless/5G; SD-WAN steers per app/SLO. → Fiber Internet • Fixed Wireless • Mobile Connectivity
☁️ Cloud & On-Ramps (Hybrid Reality)
- Keep private app flows on MPLS; burst/extend to cloud via Direct Connect/ExpressRoute/Interconnect at a carrier-dense colo. → Direct Connect • Colocation
- Use regional hubs near cloud regions; terminate MPLS there and apply breakout policy.
- For Internet-first SaaS, SD-WAN/SASE local breakout usually beats hair-pinning over MPLS.
🔒 Security Considerations (Private ≠ Encrypted)
- Add encryption where policy requires: IPsec over MPLS for sensitive flows; MACsec for L2 handoffs. → Encryption
- Zero Trust for users/admins: ZTNA instead of flat VPN; PAM for elevated tasks. → ZTNA • PAM
- Segmentation: VRF at WAN + microsegmentation in DC/cloud for lateral-movement control. → Microsegmentation
- Evidence: stream logs/flows to SIEM/SOAR. → SIEM / SOAR
🧪 Reference Designs (By Outcome)
A) Voice-First Branches
- MPLS with EF class for voice; DIA as secondary; SD-WAN packet duplication for calls on brownout; local SaaS breakout.
B) Regulated Backbone (Finance/Healthcare)
- L3VPN VRFs per domain; IPsec for PHI/PAN; DR hubs in colocation with Direct Connect to cloud records. → Colocation • Direct Connect
C) Cloud-Centric Enterprise
- MPLS to hub sites only; branches run Internet underlay + SD-WAN/SASE; private apps hair-pin to hub; everything else exits local.
🛠️ Turn-Up & Operations
- Design — VRF plan, CoS matrix, PE-CE routing (BGP), address/CIDR map.
- Order — MPLS tails per site, diversity letters, on-ramp ports, cross-connects.
- Provision — PE-CE sessions, VRFs, QoS policy, CoS marking rules, telemetry.
- Test — RFC 2544 / ITU-T Y.1564 baselines per class; synthetics for EF/AF/BE.
- Observe — tie metrics into NOC dashboards; per-class alarms; monthly SLA reviews.
- Improve — shift traffic policy from data; upgrade underlays where chronic.
💵 Commercial Notes
- Ports & tails per site; Class-of-Service uplift affects price.
- Terms typically 24–60 months; NRC for install; MRC per tail.
- Diversity (dual carriers/paths/metros) adds cost but raises availability.
- Hybrid saves — combine MPLS (critical) + DIA (bulk/SaaS) with SD-WAN policy.
✅ Pre-Engagement Checklist
- 📍 Sites, bandwidth tiers, latency classes (A/B/C), and critical apps.
- 🧠 VRF & CoS policy (EF/AF/BE allocations; policing/shaping plan).
- 🔀 PE-CE routing (BGP vs OSPF), Anycast needs, route-leak exceptions.
- 🔐 Security overlay (IPsec/MACsec, ZTNA/PAM, segmentation).
- ☁️ Cloud on-ramp strategy (which hubs/metros, which regions).
- 🔎 Synthetics & SLO definitions; evidence/reporting cadence.
🔄 Where MPLS Fits (Recursive View)
1) Grammar — private transport rules in Connectivity
2) Syntax — predictable site-to-site flows supporting Cloud architectures
3) Semantics — integrity via CoS enforcement + optional encryption → Cybersecurity
4) Pragmatics — signals for SolveForce AI to steer/forecast
5) Foundation — consistent terms under Primacy of Language
6) Map — indexed across the SolveForce Codex & Knowledge Hub
📞 Design an MPLS or Hybrid WAN You Can Prove
Related pages:
Connectivity • VPLS • SD-WAN • SASE • Direct Connect • Colocation • Fiber Internet • Fixed Wireless • Mobile Connectivity • Satellite Internet • NOC Services • Circuit Monitoring