Netlab: Using L3VPN (MPLS/VPN) with SR-MPLS Core

Why It Matters

By providing a container‑only, reproducible SR‑MPLS environment, netlab lowers the cost and complexity of testing BGP/MPLS VPN designs, accelerating service‑provider innovation and training.

Key Takeaways

• Netlab supports SR-MPLS core with containerized EOS and FRR
• LDP disabled; SR replaces label distribution
• Two VRFs provide isolated VPN services
• Graph customization improves topology visualization
• Lab runs on any Linux VM or Codespaces

Pulse Analysis

Netlab has emerged as a lightweight orchestration platform that lets engineers spin up complex MPLS environments using only Docker containers. By leveraging Arista cEOS for PE devices and FRRouting for P‑routers, the framework reproduces a production‑grade SR‑MPLS core without the overhead of physical hardware. This approach aligns with the industry’s shift toward software‑defined networking, where rapid prototyping and repeatable testbeds are essential for validating segment‑routing deployments and BGP/MPLS VPN designs. It also integrates with existing CI pipelines, enabling automated network regression testing.

Disabling LDP in the topology forces the network to rely exclusively on IS‑IS‑based segment routing for label distribution, illustrating how SR‑MPLS can replace traditional signaling protocols. The lab assigns node SIDs from distinct SRGB ranges—900 000 for PE routers and 16 000 for P routers—allowing clear separation between VPN and transport labels. Two VRFs, each connecting a pair of Linux hosts, demonstrate isolated customer routing domains while sharing the same underlying SR‑enabled core, a pattern commonly used in service provider environments. This separation simplifies troubleshooting by clearly distinguishing customer and transport label spaces.

The container‑only design means the lab can be launched on any Linux VM, WSL, or even directly in GitHub Codespaces, removing barriers to entry for students and network teams. Netlab’s graph‑generation options let users style clusters, rank core devices, and apply custom colors, producing clear diagrams that aid documentation and presentations. This level of portability and visual polish accelerates troubleshooting drills, certification prep, and proof‑of‑concept projects, reinforcing netlab’s role as a practical bridge between theoretical SR‑MPLS concepts and real‑world deployment scenarios. Furthermore, the exported PNG can be embedded directly into technical reports.