Can a switch become a router?


I have a question, that may sound stupid.
I have an 8 port switch running OpenWRT. Is it possible to set this device as router?

Meaning turning one port in a WAN port with PPPoE and using the other seven Ports as internal switch?

If it's supported by OpenWrt in the first place (realtek target), technically yes - but with abysmal performance. It's still designed as a switch, the power lies within the hardware switching matrix (which works in hardware, at line-speed), the CPU (which would be needed to do the routing) is merely an addon, whose only (intended) purpose is to present a webinterface to the user - it doesn't have the performance to do anything serious (~15 MBit/s on rtl838x at most).

tl;dr: no, not reasonably.


Can you elaborate on this? rtl838x seems to have a 500MHz CPU, while I once managed to divide up a DSL chipset's (BCM6328, 1-core 320MHz) normally LAN-only switch for routing and get the maximum speed (90+ Mbps) for the fast ethernet link.

Do the dedicated router chipsets have hardware features for NAT (that also work with normally LAN-side ports)? Or is it because they have a different level of direct access to packets?

"The iperf values are about 50MBit/s for the 8380, and about 160MBit for the 9300, the 8390 is somewhere in between."