F-Stack – A network development kit with high performance based on DPDK

The goal of this kind of system is not to replace the application server. This is intended to work on the data plane where you do simple operations but do them many time per second. Think things like load balancers, cache server, routers, security appliances, etc. In this space Kernel Bypass is still very much the norm if you want to get an efficient system.

> In this space Kernel Bypass is still very much the norm if you want to get an efficient system.

Unless you can get an ASIC to do it, then the ASIC is massively preferrable; just the power savings generally¹ end the discussion. (= remove most routers from the list; also some security appliances and load balancers.)

¹ exceptions confirm the rule, i.e. small/boutique setups

We do storage systems and use DPDK in the application, when the network IS the bottleneck it is worth it. Saturating two or three 400gbps NICs is possible with DPDK and the right architecture that makes the network be the bottleneck.

ASICs require years to develop and aren’t flexible once deployed

Even the ones supporting things like P4?

You don't develop an ASIC to run a router with, you buy one off the shelf. And the function of a router doesn't exactly change day by day (or even year by year).

Change keeps coming, even when the wire format of a protocol has ossified. I've spent years in security and router performance at Cisco, wrote a respectable fraction of the flagship's L3 and L2-L3 (tun) firewall. I merged a patch on this tried-and-true firewall just this year; it's now deployed.

As vendors are eager to remind us, custom silicon to accelerate everything between L1 to L7 exists. That said, it is still the case in 2025 that the "fast path" data-plane will end up passing either nothing or everything in a flow to the "slow path" control-plane, where the most significant silicon is less 'ASIC' and more 'aarch64'.

This is all to say that the GP's comments are broadly correct.

My colleagues are always writing new features for our edge and core router ASICs released more than 10 years ago. They ship new software versions multiple times a year. It is highly specialised work and the customer requesting the feature has to be big enough to make it worth-while, but our silicon is flexible enough to avoid off-loading to slow CPUs in many cases. You get what you pay for.