PlantUML DiagramCarrier Handoff to Customer Edge
A structured lesson workspace with readable content, hands-on examples, and a clean path to completion.
| Technology | Typical bandwidth | Cost | Latency | Best for |
|---|---|---|---|---|
| MPLS L3VPN | 10 Mbps – 10 Gbps | High | Low, deterministic | Real-time apps, mission-critical |
| Ethernet WAN (E-LAN/E-LINE) | 100 Mbps – 100 Gbps | Medium-high | Low | Metro-regional, data center interconnect |
| Business internet (broadband) | 100 Mbps – 10 Gbps | Low | Variable | General traffic, cost-sensitive sites |
| Dedicated internet access | 10 Mbps – 100 Gbps | Medium | Low to moderate | Public-facing services |
| LTE/5G | 10 Mbps – 1 Gbps | Medium | Variable | Backup, temporary sites, IoT |
| SD-WAN overlay | Aggregates any of the above | Medium | Policy-based | Modern distributed enterprise |
Every WAN choice is a trade-off between cost, performance, and reliability. MPLS delivers SLA-backed latency and jitter — at a premium. Broadband is cheap and fast but has no SLA. SD-WAN lets you use both and make routing decisions based on application requirements.
The single biggest operational difference: you can't see the WAN. Troubleshooting is often 'open a ticket and wait.' This is why SLA-based contracts and dedicated circuit monitoring tools matter at scale. Even with SD-WAN overlays, the underlying transport is still someone else's problem to fix.
The demarcation point (demarc) is the boundary between carrier and customer. Above it, the carrier is responsible. Below it, you are. When a WAN link fails, the first diagnostic question is 'which side of the demarc is the problem?' — because the answer determines who gets paged.
WAN is the network you rent. MPLS for critical workloads, broadband for cost-sensitive, SD-WAN for modern flexibility. The demarc separates your responsibility from the carrier's. Next lesson compares internet and broadband options.
Finish the lesson once you have worked through the material. This awards ★ 15 XP.