Internet Speed is very low with ppp in modem shell for nrf9160.

[Shaik Arif]

I am connecting to Nordic nrf9160 from linux through PPP of modem shell application for internet connection. I am observing very slow internet speed where it is taking approximately 1.30 minutes to download 1MB of data. Below are some test results.

time wget http://speedtest.ftp.otenet.gr/files/test1Mb.db 

Connecting to speedtest.ftp.otenet.gr (212.205.74.89:80)

saving to 'test1Mb.db'

test1Mb.db            42% |***********************                                 |  430k  0:00:49 ETA

test1Mb.db           100% |********************************************************| 1024k  0:00:00 ETA

'test1Mb.db' saved

 

real    1m32.443s

user    0m0.022s

sys 0m0.093s

time wget speedtest.ftp.otenet.gr/files/test1Mb.db

Connecting to speedtest.ftp.otenet.gr (212.205.74.89:80)

saving to 'test1Mb.db'

test1Mb.db 45% |************************* | 463k 0:00:35

test1Mb.db 100% |********************************************************| 1024k 0:00:00 ETA

'test1Mb.db' saved

 

real 1m29.821s

user 0m0.018s

sys 0m0.092s

I want to know is there any possibility of increasing the speed? or what speed I am getting here is the expected one from this hardware. 

[Susheel Nuguru]

Shaik,

We need more information on your setup

1. Are you using LTE-M or NB-IoT?
2. What baud rate are your using on the PPP connection?
3. How are the signal conditions?
4. What result do you get when you use the iperf command (both over PPP and on the 91 directly)

[Shaik Arif]

Are you using LTE-M or NB-IoT?

LTE-M

What baud rate are your using on the PPP connection?
921600

How are the signal conditions?
Good

What result do you get when you use the iperf command (both over PPP and on the 91 directly)

Below are the results

91 Directly

With PPP

mosh:~$ iperf3 --client ping.online.net --port 5200 -l 3540 --time 30 -V -R iperf 3.9-nrf nrf9160 Control connection MSS: using modem default Time: Thu, 01 Jan 1970 00:00:56 GMT Connecting to host ping.online.net, port 5200 Reverse mode, remote host ping.online.net is sending Cookie: nrf9160.55.935180.4bb5f64647033129.1 TCP MSS: 0 (default) [ 4] local 0.0.0.0 port 0 connected to 62.210.18.40 port 5200 stream [0]: socket: 4 read: 1 write: 0 Starting Test: protocol: TCP, 1 streams, 3540 byte blocks, omitting 0 seconds, 30 second test, tos 0 [ ID] Interval Transfer Bitrate [ 4] 0.00-1.01 sec 13.8 KBytes 112 Kbits/sec [ 4] 1.01-2.01 sec 11.8 KBytes 96.3 Kbits/sec [ 4] 2.01-3.01 sec 15.2 KBytes 125 Kbits/sec [ 4] 3.01-4.01 sec 16.6 KBytes 136 Kbits/sec [ 4] 4.01-5.01 sec 15.9 KBytes 130 Kbits/sec [ 4] 5.01-6.01 sec 16.6 KBytes 136 Kbits/sec [ 4] 6.01-7.01 sec 10.4 KBytes 85.0 Kbits/sec [ 4] 7.01-8.01 sec 12.4 KBytes 102 Kbits/sec [ 4] 8.01-9.01 sec 14.5 KBytes 119 Kbits/sec [ 4] 9.01-10.01 sec 21.4 KBytes 176 Kbits/sec [ 4] 10.01-11.01 sec 19.4 KBytes 159 Kbits/sec [ 4] 11.01-12.01 sec 14.5 KBytes 119 Kbits/sec [ 4] 12.01-13.01 sec 16.6 KBytes 136 Kbits/sec [ 4] 13.01-14.01 sec 13.1 KBytes 108 Kbits/sec [ 4] 14.01-15.01 sec 17.3 KBytes 142 Kbits/sec [ 4] 15.01-16.01 sec 14.5 KBytes 119 Kbits/sec [ 4] 16.01-17.01 sec 4.15 KBytes 34.0 Kbits/sec [ 4] 17.01-18.01 sec 11.8 KBytes 96.3 Kbits/sec [ 4] 18.01-19.01 sec 18.7 KBytes 153 Kbits/sec [ 4] 19.01-20.01 sec 18.7 KBytes 153 Kbits/sec [ 4] 20.01-21.01 sec 18.0 KBytes 147 Kbits/sec [ 4] 21.01-22.01 sec 9.68 KBytes 79.3 Kbits/sec [ 4] 22.01-23.01 sec 12.4 KBytes 102 Kbits/sec [ 4] 23.01-24.01 sec 17.3 KBytes 142 Kbits/sec [ 4] 24.01-25.01 sec 18.7 KBytes 153 Kbits/sec [ 4] 25.01-26.01 sec 13.8 KBytes 113 Kbits/sec [ 4] 26.01-27.01 sec 15.2 KBytes 125 Kbits/sec [ 4] 27.01-28.01 sec 18.7 KBytes 153 Kbits/sec [ 4] 28.01-29.01 sec 15.9 KBytes 130 Kbits/sec [ 4] 29.01-30.01 sec 15.9 KBytes 130 Kbits/sec - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 4] 0.00-30.01 sec 507 KBytes 138 Kbits/sec 0 sender [ 4] 0.00-30.01 sec 453 KBytes 124 Kbits/sec receiver iperf Done.

iperf3 --client ping.online.net --port 5203 -l 3540 --time 30 -V -R iperf 3.11 Linux mosdon-rev-a 5.15.32-lts-next+gfa6c3168595c #1 SMP PREEMPT Tue Jun 7 02:34:46 UTC 2022 aarch64 Control connection MSS 1228 Time: Thu, 13 Apr 2023 10:16:27 GMT Connecting to host ping.online.net, port 5203 Reverse mode, remote host ping.online.net is sending Cookie: ha6dw5nabsllyqxbwhd6ve7ns2xsrnurlac2 TCP MSS: 1228 (default) [ 5] local 10.43.19.107 port 46902 connected to 62.210.18.40 port 5203 Starting Test: protocol: TCP, 1 streams, 3540 byte blocks, omitting 0 seconds, 30 second test, tos 0 [ ID] Interval Transfer Bitrate [ 5] 0.00-1.00 sec 27.4 KBytes 225 Kbits/sec [ 5] 1.00-2.00 sec 22.8 KBytes 187 Kbits/sec [ 5] 2.00-3.00 sec 27.6 KBytes 226 Kbits/sec [ 5] 3.00-4.00 sec 26.4 KBytes 216 Kbits/sec [ 5] 4.00-5.00 sec 24.0 KBytes 196 Kbits/sec [ 5] 5.00-6.00 sec 22.8 KBytes 187 Kbits/sec [ 5] 6.00-7.00 sec 26.4 KBytes 216 Kbits/sec [ 5] 7.00-8.00 sec 25.2 KBytes 206 Kbits/sec [ 5] 8.00-9.00 sec 25.2 KBytes 206 Kbits/sec [ 5] 9.00-10.00 sec 26.4 KBytes 216 Kbits/sec [ 5] 10.00-11.00 sec 22.8 KBytes 187 Kbits/sec [ 5] 11.00-12.00 sec 25.2 KBytes 206 Kbits/sec [ 5] 12.00-13.00 sec 20.4 KBytes 167 Kbits/sec [ 5] 13.00-14.00 sec 21.6 KBytes 177 Kbits/sec [ 5] 14.00-15.00 sec 21.6 KBytes 177 Kbits/sec [ 5] 15.00-16.00 sec 9.59 KBytes 78.6 Kbits/sec [ 5] 16.00-17.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 17.00-18.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 18.00-19.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 19.00-20.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 20.00-21.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 21.00-22.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 22.00-23.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 23.00-24.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 24.00-25.00 sec 104 KBytes 855 Kbits/sec [ 5] 25.00-26.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 26.00-27.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 27.00-28.00 sec 0.00 Bytes 0.00 bits/sec [ 5] 28.00-29.00 sec 69.6 KBytes 569 Kbits/sec [ 5] 29.00-30.00 sec 0.00 Bytes 0.00 bits/sec - - - - - - - - - - - - - - - - - - - - - - - - - Test Complete. Summary Results: [ ID] Interval Transfer Bitrate Retr [ 5] 0.00-30.00 sec 899 KBytes 245 Kbits/sec 4 sender [ 5] 0.00-30.00 sec 549 KBytes 150 Kbits/sec receiver rcv_tcp_congestion cubic iperf Done.

[Susheel Nuguru]

Showed the info you provided to my colleague who has deep understanding on this. Typically getting speeds around 180kb/s (not using PPP) is normal, so these does not look too bad but could have been little better.

Try Increasing the shared memory buffers between the modem and application cores might help a bit (look at the Kconfig file for the modem lib). You could also try to increase the baudrate to 1000000, though I don't think the UART interface is what is limiting in your case.

For comparison, you can find the peak rates of the physical layer (so the application will see lower numbers) here: https://www.nordicsemi.com/-/media/Software-and-other-downloads/Product-Briefs/nRF9160-SiP-product-brief.pdf?sc_trk={Download%20product%20brief}