[clug] ADSL2+ speeds

steve jenkin sjenkin at canb.auug.org.au
Thu Feb 12 05:19:51 GMT 2009

This week I cancelled an ADSL2+ service via Optus infrastructure:
  a massive 3Mbps...
  compared to 5.3Mbps achievable on ADSL1

This was a deliberate experiment - if Naked ADSL2 had worked better, I
have moved it ;-)
costs: $189 connection fee for a 2nd line, $40 ADSL2 setup fee and ISP
$100 contract cancellation fee.

A previous attempt two years ago was a disaster - 1.5Mbps only and ISP
wouldn't/couldn't revert to original service.
Took 6 months and 4 attempts to get back to ADSL1.

Today I happened to look at Internode plans and found this graph:

On ADSL1 to get 5Mbps, I must be around 3500m from the exchange (correct)...
Which this graph says is way beyond the fast performance limits of ADSL2+.

But still says 'expect more' of ADSL2+ - which was what I was hoping for.

Do we believe the chart?
It looks to have the speed/distance effects laid out OK - but wait,
there's more!

The perfect graph assumes constant sized cable - and probably little or
no jointing.

But Telecom/Telstra was always 'cheap' - they laid thinner cable to save
money (copper gets expensive). Was that the '70's or '80's?? Don't know.

This is the underlying reason ADSL in Oz can't achieve the same
performance/distance as overseas...
Cheap-arsed cable plant :-(

How come *two* ISP's failed to recognise the laws of physics?

The first was quite blatant - "We are only required to provide you
1.5Mbps." ('get stuffed' was implied). I spent a whole lot of time
monitoring the line (grabbing stats from my firewall/router) - and could
show a bunch of effects - diurnal variation and rapid decay of S/N ratio
after a connection.

The link would start with SNR of 10-12db - and end with -0.5db usually
after 30mins. I.e. the *noise* was louder than the signal.
Which I interpreted as an active device on the line (not a passive
effect) and given it was a brand new DSLAM, could've been caused by a
simple installation fault.
I ended up having explain 'dB' to one of their 'network engineers'.
Having provided data and suggested the above explanation, I invited them
to provide an alternative - they refused point blank.

With the second ISP, I had a long email exchange and then on Day 3 rang
the 'support line'. Around 40 min on hold, quoted my fault number - and
was *twice* hung-up on without them speaking. Wrote to their
'resolution' address - no acknowledgement or reply.
Cancelled the service that day. The 'help desk' staff are either
unmonitored or under instruction to do this - would never be good for me.


Steve Jenkin, Info Tech, Systems and Design Specialist.
0412 786 915 (+61 412 786 915)
PO Box 48, Kippax ACT 2615, AUSTRALIA

sjenkin at canb.auug.org.au http://members.tip.net.au/~sjenkin

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