[alfalfasprout]

Nowadays GPUs are a poor choice for this. GPUs have fairly high latency and are designed to be optimal for embarrassingly parallel computations. Sure you can do 10gigabits/sec but because you're batching that'll result in your latency being high-ish on average.

In terms of non-CPU hardware for routing FPGA's are still king if you need a bit of flexibility. In theory a rule table can be defined in configs and then flashed onto the FGPA for line-speed packet processing. Even then, given how slow FPGA's are to flash CPUs are still king when general packet processing is needed.