[GTALUG] war story: bad ADSL packet loss
D. Hugh Redelmeier
hugh at mimosa.com
Mon Jan 5 23:46:10 UTC 2015
My internet connections are confusing and complicated so I will spare you
One connection is via ADSL2 to telnetcommunications.com. It started
to get flaky. I measured 50-90% packet loss over various periods of
I also have a VDSL2 connection with telnetcommunications.com that did
not have the problem. Tentative conclusion:
telnetcommunications.com's network is not the problem.
I use a TP-Link TD-8816 as a modem, but not as a router. I have a
Linux box that does the PPPoE thing.
I tried: powercycling things, one at a time, to see if things got
better. They didn't.
I tried: phoning support. They suggested switching phone cable or
ethernet cable before trying to talk to Bell.
I tried: switching cables. No change.
I tried: taking other phones off phone line and removing splitter
where the ADSL modem was connected to the wall jack. No change.
I tried: swapping ADSL modem for an identical one, purchased at the
same time. It worked!
- being a hoarder has its advantages (why did I buy two ADSL modems 3.5
- being a hoarder has its disadvantages. Both modems are out of (2
year) warranty. The splitter that came with the newly unwrapped
modem doesn't work and I have no recourse.
- ADSL modems sometimes fail. My previous ADSL modem (Speedstream
something or other) failed, but I don't remember the symptoms.
- ADSL modems don't always fail hard.
- with so many pluggable parts, there is a very large number of
configurations to test. The modem has: power, phone, ethernet,
all of which could have been swapped. The wall jack needs
a splitter, an ADSL filter on one side, and cables connecting all
of these. Of the right length. And other jacks in the house need
to be played with too.
I didn't even bother to see if the replacement modem would work as
well with the original modem's power supply, or vice versa. Life's
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