Killing the ISP Appliance: An eBPF/XDP Approach to Distributed BNG

Killing the ISP Appliance: An eBPF/XDP Approach to Distributed BNG

I used to work for an ISP startup that was building next-generation infrastructure. The company didn’t make it, but the problems we were trying to solve stuck with me. So I spent a few weeks building what we never got to: an open-source, eBPF-accelerated BNG that runs directly on OLT hardware.

This post explains the architecture and why I think it’s the future of ISP edge infrastructure.

The Problem: Centralised BNG is a Bottleneck

Traditional ISP architecture looks like this:

Customer → ONT → OLT → [BNG Appliance] → Internet ↑ Single point of failure Expensive proprietary hardware All subscriber traffic flows through here

Every subscriber’s traffic - DHCP, authentication, NAT, QoS - flows through a central BNG appliance. These boxes cost six figures, require vendor support contracts, and create a single point of failure. When they go down, everyone goes down.

The industry’s answer has been to buy bigger boxes with more redundancy. But what if we flipped the model entirely?

The Idea: Distribute the BNG to the Edge

What if, instead of funneling all traffic through a central appliance, we ran BNG functions directly on the OLT hardware at each edge site?

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