Archetype 1 — the open-source generalist
The clearest example is VyOS. It's a genuinely capable, Debian-based network operating system: routing, firewalling, NAT, VPN, and — through the accel-ppp subsystem — PPPoE and IPoE subscriber termination. For a lab, an edge router, or an engineer who enjoys building their own stack, it's excellent, and the price of entry is appealing.
But notice what it is. VyOS is a general-purpose router OS in which IPoE is a small corner of a much larger system. That has real consequences for an operator running it as a production BNG:
- You are the integrator. IPoE subscriber management via
accel-pppis a component you assemble, tune, and validate yourself — RADIUS integration, Option 82 handling, scaling behavior, high-availability, accounting. The pieces exist; making them a coherent, resilient BNG is your project, not the vendor's product. - You own the whole attack and patch surface. Every subsystem the OS ships — much of which you'll never use as a BNG — is still code you must track for CVEs, patch, and regression-test. Breadth you don't need is still risk you carry.
- Support is a community, not an SLA. When a subscriber-management edge case bites at 2 a.m., the answer is a forum thread, a mailing list, or your own packet captures. For a lean operator with no BNG specialist on staff, that is the expensive part — measured in outage minutes, not license fees.
The generalist's low sticker price is real, but it quietly relocates the cost from the purchase order to your operations team. You didn't buy a BNG; you bought the parts and the job of being your own BNG vendor.