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data mobile connection && changes in RT value

To: ubuntu-phone <ubuntu-phone@xxxxxxxxxxxxxxxxxxx>
From: Matthias Apitz <guru@xxxxxxxxxxx>
Date: Fri, 31 Mar 2017 07:37:37 +0200
Mail-followup-to: Matthias Apitz <guru@xxxxxxxxxxx>, ubuntu-phone <ubuntu-phone@xxxxxxxxxxxxxxxxxxx>
Reply-to: Matthias Apitz <guru@xxxxxxxxxxx>
User-agent: Mutt/1.8.0 (2017-02-23)

Hello,

I'm using my BQ E4.5 as an AP to connect my netbook to the Internet. I
encounter an interesting effect. This shows a ping running as user
phablet in the BQ to some local side here in Munich:

64 bytes from 193.149.48.8: icmp_seq=74 ttl=50 time=48.8 ms
64 bytes from 193.149.48.8: icmp_seq=75 ttl=50 time=47.7 ms
64 bytes from 193.149.48.8: icmp_seq=76 ttl=50 time=50.6 ms
64 bytes from 193.149.48.8: icmp_seq=77 ttl=50 time=51.0 ms
64 bytes from 193.149.48.8: icmp_seq=78 ttl=50 time=49.7 ms
64 bytes from 193.149.48.8: icmp_seq=79 ttl=50 time=273 ms
64 bytes from 193.149.48.8: icmp_seq=80 ttl=50 time=263 ms
64 bytes from 193.149.48.8: icmp_seq=81 ttl=50 time=272 ms
64 bytes from 193.149.48.8: icmp_seq=82 ttl=50 time=251 ms
64 bytes from 193.149.48.8: icmp_seq=83 ttl=50 time=271 ms
64 bytes from 193.149.48.8: icmp_seq=84 ttl=50 time=321 ms
64 bytes from 193.149.48.8: icmp_seq=85 ttl=50 time=281 ms
64 bytes from 193.149.48.8: icmp_seq=86 ttl=50 time=52.5 ms
64 bytes from 193.149.48.8: icmp_seq=87 ttl=50 time=50.7 ms
64 bytes from 193.149.48.8: icmp_seq=88 ttl=50 time=50.9 ms
64 bytes from 193.149.48.8: icmp_seq=89 ttl=50 time=51.5 ms

Please note the change in the RT (round trip) value from ~50ms to ~270ms and
back to ~50ms. The (reproducible) change happens went I stop real
traffic through the BQ, in this test case I just have a SSH session from
my netbook to some side and running a top command there. When I stop the
top command (which does every second a new output to the terminal through the
SSH), the RT value goes up. It goes down again when I restart the top.

There is no visible change in the BQ status line, i.e. it is not going
from 'H' to 'E'.

What does this mean?

Is there some way to query with modem AT commands the status and quality
of the data connection?

	matthias
-- 
Matthias Apitz, ✉ guru@xxxxxxxxxxx, ⌂ http://www.unixarea.de/  ☎ +49-176-38902045
Aus "Nie wieder Krieg!" wurde "Nie wieder Krieg ohne Deutschlands Truppen"
The "No wars anymore!" changed now to "No wars anymore without German battle groups!"
El "¡Nunca jamás guerra!" ha cambiado a "¡Nunca jamás guerra sin tropas alemanas!"