[LINK] 1.5 Mbps limit lifted from Telstra's ADSL DSLAMs?

Robin Whittle rw at firstpr.com.au
Wed Jan 17 15:55:36 AEDT 2007

I rebooted my server, and therefore the ADSL link and had the new
improved speed this afternoon.

Using the Java applet DSL speed test at:


on a Windows machine, going via the Linux machine to the ADSL link:

          Downstream                Upstream
Before    1267 kbps = 154.7 kBps    303 kbps = 37.0 kBps

After     3137 kbps = 383.0 kBps    304 kbps = 37.1 kBps

These are application data throughput rates.  So this is 2.5 times the
original speed, which resulted from a 1500 kbps limit on the actual
communication link.  The "before" tests were done with the mail server
running, so if emails were coming in, then the reported figure is an
underestimate of the true speed of the link.

The wget HTTP download from http://mirror.aarnet.edu.au used to run at
about 155 kBps (with the mail server running).  Now it runs consistently
at 411 kBps, which is 2.66 times the original speed.

So this is $10 a month well spent!  Uplinks are no faster.

I would say the underlying downstream rate is ~2.5 x 1500 ~= 3.75 to 4
Megabits per second.

Taking the most likely route of main roads from the Heidelberg
"exchange" building to our home, we are about 3.6 km from the DSLAM.
This area was developed in the 1950s and 1960s.  The pit outside is 1980
or 1990s vintage, with a black plastic cable inside, which I guess is 50
pair or so.  I am not sure if this is original wiring or not.  Some
nearby streets have aerial distribution of the phone wires to houses,
with either aerial cable or buried cable running up the poles, but ours
is all underground.  Maybe they rewired the street in the 1970s or 1980s.

  - Robin

More information about the Link mailing list