I have a minimal CentOS 6.3, 64 bit acting as gateway with 4 NIC (1 Gbps), each bonded together one for public traffic and other for private, which performs NATing. It has 6 GB RAM and 4 logical cores. We have been using this for the past two years without any problems.
I don't have any experience with hardware routers, but I have heard that they have less RAM and CPU and use flash disks. How can a box with low hardware configuration perform better (as in, handle more concurrent connections) than a machine with more RAM and CPU?
What are the limiting factors, other than IOS using different methods to handle this?