I've been looking at the block diagrams of various RouterBOARD products, and something noticeable is that a lot of switch chips have a bottleneck from CPU to the ports. No problem, who routes over 2 Gbps and isn't an ISP anyway?
What I wonder, is whether the bandwidth shown is full-duplex (if it says 1 Gb/s, it can do full 1 Gbps on both directions at the same time, combined 2 Gbps) or combined half-duplex (it says 1 Gb/s, but I can only do 800 Mbps on one side if the other uses 200 Mbps, or 500/500 Mbps)?
This can definitely be useful when routing somewhere out of the switch chip itself (through the CPU), for example, using another switch chip, or using the WiFi chip (which is always wired to the CPU).
sorry for my english, apologies in advance