On Mon, 21 Mar 2016 12:15:56 -0000 (UTC) Dan Purgert <d...@djph.net> wrote:
> On 2016-03-18, Celejar <cele...@gmail.com> wrote: > > Hi, > > > > I'm trying to understand the throughput across the different links of > > my little home network, and am perplexed by the measured wireless > > throughput. > > > > The three main devices I'm interested in: > > > > Router: Buffalo WZR-HP-G300NH running OpenWrt (Chaos Calmer 15.05). > > Gigabit WAN and LAN, 802.11bgn wireless. > > I know I'm coming to the party a bit late, and it's probably been > answered somewhere else in the posts here, but what channel width are > you running here? > > If you're running 40 MHz, you WILL be getting combined Co-channel > contention from all other devices on channels 1 and 6 (or 6 and 11). > With 2.4 GHz connections, it's advisable to stick to 20 MHz channels, to > limit the amount of contention you're getting. Running at 20 MHz. > > [...] > > > > Here's the part that baffles me - these are with the laptop connected > > to the router wirelessly: > > > > Laptop - router: ~11.8 Mbps > > > > These numbers actually exhibit significant variance, but they're > > generally at least this much, and at most about 15-20 Mbps. > > > > Laptop - NAS: ~14.7 Mbps > > > > Once again, these numbers vary widely, but are in line with the laptop > > - router numbers. > > > > But here's the kicker: Ookla's speedtest (run on the laptop with > > speedtest-cli) shows 29.01/5.89 (d/u), and this is fairly consistent. > > > > [...] > > > > So the wireless link can apparently push at least 30 Mbps or so, so why > > are my local wireless throughput numbers so much lower? > > Given that the router is a 2x2 device, have you tried sending multiple > streams with iperf (with the "-P" client option)? As I (likely, > incorrectly) recall, iperf defaults to one stream, whereas speedtest > will run multiple streams. Just tried a few runs with "-P 2" - no difference. > > I was originally using one of the common 1/6/11 channels, and I switched > > to 3 since I saw a lot of other stations on those channels. This may > > have resulted in some improvement, but I'm still stuck locally as > > above. What's the explanation for this - how can I possibly be getting > > much better throughput to servers tens of miles away than to my local > > stations? Does iperf somehow work fundamentally differently from > > speedtest? If so, which is a better representation of actual throughput? > > Switch back to 1, 6, or 11 (and a 20 MHz channel). As others have > explained, being on an "in-between" channel will result in you getting > actual interference (rather than simply co-channel contention) ... not > to mention causing interference for your neighbors. > > It might be a good idea to upgrade to a dual-band access point, so that > you can use 5 GHz, which is typically has much cleaner channels. Thanks. See my other response in the thread regarding channel selection. Celejar
