Hi. I don't want to hijack your thread, but since this is about router performance, maybe both our questions are related? If not, this can be moved into it's own thread, but I thought it may be helpful to both of us to combine the questions.

So, we have recently upgraded our backhauls on the first couple hops to wireless gear that carries ~700 Mbit of throughput. We have 2 Pairs of radios - so we can call them A-B and C-D. 'A' is wired to our switch at the shop, and it is linked wirelessly to 'B' (and can carry ~700 Mbit). On the same tower as 'B', we have the start of the C-D link, so 'C' in on the same tower as 'B', and 'C' and is linked wirelessly across town to 'D'. So, if I try to diagram this, we have:


If we connect it like that, and test from a computer connected behind 'D' to a server at the shop connected to the switch behind 'A', then we can get ~700 Mbit of throughput end to end. However, when we connect between 'B' and 'C' (in order to feed the AP's on that tower) with a StarOS board, the end-to-end throughput drops to about 350 Mbit. All those Ethernet connections are GigaBit, and the boards are PC-Engines APU's (Version 4.3.4n, 3x GigaBit Ethernet, DualCore 1Ghz CPU, 2 GBytes RAM). Since the Radio Units themselves are bridges, we have the radios themselves 'A', 'B', 'C', and 'D' all addressed 10.0.0.x numbers. When we put the APU board in between 'B' and 'C', the APU board itself also has a 10.0.0.x number, and we've bridged Ether1 and Ether3, and Connection Tracking is off. When the APU board in in the middle, the end-to-end link performance is about 1/2 of capacity. If we replace the APU board with a cable, we get ~700 Mbit speed (so it's not co-location interference) and if we replace the APU board with a $40 Gigabit switch, we get full speed to.

So, I thought I'd test this in the shop. I have three APU boards - let's call them APU-A, APU-B and APU-C. If I setup APU-A and APU-C so that they route between the two, and if I do an iPerf test over an ethernet cable, I can get ~950 Mbit between them. If I run that test through APU-B (again bridging Ether1 and Ether3 on APU-B) then the APU-A-to-APU-B throughput drops to ~510 Mbit. If I change APU-B from bridging to routing, again the performance is about 510 Mbit. If I replace the APU-B board with a VENTANA in the middle, again the performance through a VENTANA Ethernet-Ethernet bridge is about 510 Mbit. If I replace the StarOS Bridge with a $40 switch, then the APU-A to APU-C throughput is ~950 Mbit.

So - I'm not necessarily reporting a problem exactly... I was just surprised by the result, and since there was this routing-performance thread, I thought I'd add this info into the mix in case it's relevant to rafamous's question. I haven't yet tested this in a bunch of different configurations, and I yet haven't tested this with other types of router operating systems, or tested with other versions of Star - and we only recently upgraded our Backhaul to make this apparent anyway.