topic Re: Fast upload but abysmal download in Unleashed

Fast upload but abysmal download

aeridith — Thu, 19 May 2022 03:00:36 GMT

Hi there,

Getting extremely good speeds uploading (1200Mbps) via speedflex but bad speeds when uploading(350Mbps). Any idea what the culprit could be?

Source device: iPhone 13 802.11ax WIFI-6

Destination: Ruckus 750 with 802.3at

Cheers,

Aeridith

Re: Fast upload but abysmal download

aeridith — Thu, 19 May 2022 03:05:27 GMT

Re: Fast upload but abysmal download

Squozen — Thu, 19 May 2022 10:17:54 GMT

I have similar results on an iPhone 12 with an R650.

Re: Fast upload but abysmal download

DarrelRhodes — Thu, 19 May 2022 13:44:31 GMT

Hi Aeridith,

I don't believe SpeedFlex is giving you accurate data, as the iPhone 13 doesn't have the hardware capability to push 1.2Gbps via Wi-Fi.

I have an iPhone 13 Pro Max and on my 900Mbps FTTP circuit, with 80MHz channels on a Ruckus R750 with a 2.5Gbps Ethernet connection, the max throughput I've seen (using Ookla Speedtest.net) is 616Mbps.

The MCS11 rate for a 2-stream 802.11ax device (such as the iPhone) @80Mhz channel width, with short guard-interval is 1,201Mbps. This would usually result in a TCP throughput of 40-60% - at most, approx 720Mbps.

I would recommend using an internet-based speed-test or local iPerf server to determine true TCP throughput. As detailed here: https://support.ruckuswireless.com/articles/000003772

I hope that helps,
Darrel.

Re: Fast upload but abysmal download

Squozen — Thu, 19 May 2022 14:47:47 GMT

I've seen 846Mbps from my iPhone 12 on Speedtest. The internet is very good here though.

Re: Fast upload but abysmal download

DarrelRhodes — Thu, 19 May 2022 15:30:54 GMT

846Mbps would be incredible, regardless of the internet speed!

Further details here: https://support.apple.com/en-gb/guide/deployment/dep268652e6c/web on iPhone capabilities, please remember that PHY rate is the. same as data rate and does not equate to TCP throughput, which is usually 40-60% of the PHY rate (depending on lots of factors!).

Best,
Darrel.

Re: Fast upload but abysmal download

aeridith — Sat, 21 May 2022 17:47:20 GMT

Thanks @DarrelRhodes !

I actually went to that page and saw that iPhone 11 and later has 1200 Mbps Maximum PHY. If I use iperf3, I'm seeing ranges of 791 Mbit/s download and 737 Mbit/s upload so based on your math that means I'm getting great speeds.

After seeing other posts - I agree with your assessment that the speedflex tool is inaccurate. I'm currently trying to track down network gremlins (video conferencing, cameras, WIFI calling, zeroconf are all having wildly different behaviors).

One of the less talked about issues is background chattiness on the network. I'm sitting in front of the router with WIFI 6 and I see ping rates like this - I can't help wonder if there is a relation between the issues above and these ping results. BTW CPU is 3% with 2 as the load on a macbook pro.

64 bytes from 192.168.250.1: icmp_seq=17 ttl=64 time=2.027 ms
64 bytes from 192.168.250.1: icmp_seq=18 ttl=64 time=1.637 ms
64 bytes from 192.168.250.1: icmp_seq=19 ttl=64 time=41.165 ms
64 bytes from 192.168.250.1: icmp_seq=20 ttl=64 time=86.733 ms
64 bytes from 192.168.250.1: icmp_seq=21 ttl=64 time=128.615 ms
64 bytes from 192.168.250.1: icmp_seq=22 ttl=64 time=172.465 ms
64 bytes from 192.168.250.1: icmp_seq=23 ttl=64 time=219.487 ms
64 bytes from 192.168.250.1: icmp_seq=24 ttl=64 time=1.987 ms
64 bytes from 192.168.250.1: icmp_seq=25 ttl=64 time=13.264 ms
64 bytes from 192.168.250.1: icmp_seq=26 ttl=64 time=3.427 ms
^C
--- 192.168.250.1 ping statistics ---
27 packets transmitted, 27 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.637/38.004/221.103/66.654 ms

Am I chasing the wrong thing when it comes to speed and ping?

Re: Fast upload but abysmal download

Squozen — Mon, 23 May 2022 09:46:55 GMT

I have the results right here. 😀

Original iPhone test: https://www.speedtest.net/my-result/i/5117165449

iPad test from a few minutes ago: https://www.speedtest.net/my-result/i/5125264400

2015 MacBook Pro - https://www.speedtest.net/result/d/431706937

The datacentre I'm testing against is only 12kms from my house and I'm on 1000/200 fibre.

Re: Fast upload but abysmal download

Squozen — Sun, 22 May 2022 18:20:57 GMT

I would skip ping and pull out Wireshark to see what chatter you're getting on both the wired and wireless networks. Can you describe the network a little? How many devices?

Re: Fast upload but abysmal download

DarrelRhodes — Tue, 24 May 2022 16:18:05 GMT

Hi Aeridith,

Thanks for your message. Whilst ping isn't a stand-alone indicator of anything specific, it can certainly play an important part of understanding the full picture of what is happening with the wireless network and underlying environment.

High levels of jitter (ping response time variations) can certainly be an indicator of underlying high levels of interference. I would suggest investigating a change of channels, perhaps implementing ChannelFly and ensuring clients are using 5GHz where possible.

Re: Fast upload but abysmal download

aeridith — Tue, 24 May 2022 18:29:52 GMT

Thanks for the suggestions @DarrelRhodes @Squozen

Including some tests with iperf with a direct connection to 2.5Gbps port to R750 and the backend server. I'm really trying to go for 800Mbps+ as well as a stable ping.

49 devices spread between two Ruckus 750 APs (22+27). Already using Channelfly and in a rural area.

Using wireshark, I see something reflective of ping spikes where it seems that the whole connection both internal and external seem to have an issue. There are also MDNS log entries but it's interesting that some of this is happening over ipv6 over the private network (fe80::).