I’m about to do some throughput tests as well. Testing with Espresso Bin and buildroot-2015.11-16.08 and I am going to use a smartbits device for throughput testing in router mode.
Seeing that the switch is apparently connected via RGMII with a 2.5 Gbps link:
<snip>
U-Boot 2015.01-armada-17.02.0-gc80c919 (Mar 04 2017 – 15:51:07)
I2C: ready
DRAM: 1 GiB
Board: DB-88F3720-ESPRESSOBin
CPU @ 800 [MHz]
L2 @ 800 [MHz]
TClock @ 200 [MHz]
DDR @ 800 [MHz]
Comphy-0: PEX0 2.5 Gbps
^^^^^^^^
Comphy-1: USB3 5 Gbps
Comphy-2: SATA0 5 Gbps
</snip>
and the link to the switch itself is reported as 1Gps:
<snip>
# ip link set dev eth0 up
# [ 404.704060] mvneta d0030000.ethernet eth0: Link is Up – 1Gbps/Full – flow control off
</snip>
I’m not sure about the switches capability to get faster than the reported 1Gbps via RGMII, but 2.5Gbps would be the upper limit, right ?
Then I would suspect that we will see no more than 1.25Gbps bidirectional throughput going from lan1 to wan interface while using the CPU for routing. That would be ~750Mbps unidirectional per port.
The upper limit for a gbit network is ~2Gbps throughput bidirectional, which means the connection between switch and CPU would have to manage ~4Gbps when routing/NATing between lan1 and wan for example. I’ll try to test also with an additional USB3.0 network adapter connected to Comphy-1, to get a little bit less of a bottleneck on the RGMII bus.
