On 14/06/2011, at 6:50 PM, John Daniels wrote:
>
> Hi everyone
>
> I am still being plagued with a big reduction in speed in the evening. Up
> until 3.20pm it was 162KBs, then went to 90KBs and 50KBs
>
> Has anyone else on Hammersley Exchange experienced this?
>
> Cheers
>
> John
Hi John,
More details might help you get some advice.
What Modem?
What sync / attenuation stats is your modem reporting? (Line Speed /
Attenuation / Noise details)
What MTU setting do you have on your modem router? The MTU setting of your
router will lead to performance issues if set too high or too low.
The normal MTU (Maximum Transmit Unit) value for most Ethernet Networks is 1500
Bytes, or 1492 Bytes for PPPoE connections.
Have you tried an Isolation Test?
Isolation Test
So, you are on ADSL or ADSL2/2+ and are having some problems, someone has told
you to do an isolation test and you have no idea what that is.
What is an Isolation test
Basically an Isolation test is when you remove all telephony devices in your
premises from the phone line. These can include ADSL filters, phones, faxes,
answering machines, Foxtel Digital (or any other Digital PayTV), EFTPOS
machines, back-to-base alarm systems, dialup modems, medical alterting systems
etc – basically anything that plugs into the phone line.
After all devices have been removed, plug your ADSL broadband modem directly
into the first phone socket into the house, bypassing any ADSL
filters/splitters (just to eliminate these as a possible problem). The first
socket is generally the one in the common area of the house (kitchen or
lounge/front room), but you may have to consider where the line comes into the
house and trace it if necessary – especially if multiple sockets have been
installed. Use the shortest phone cable you have (ie 1-2m), and try another
phone cable if there is no luck with the first. Try various phone sockets in
the house if what you think is the first socket doesn't work; it's not
impossible for a single socket to have a fault, and if the house has a central
filter fitted then some sockets may have no ADSL signal at all by design.
Monitor the Internet connection for the difficulty you were experiencing to see
if it clears. If the problem is still there, refer notes below.
If the difficulty you were experiencing clears, then you can connect one filter
and one telephony device to your phone line, and monitor your internet
connection again for the difficulty you were experiencing.
By connecting telephony devices one by one, and testing your internet
connection each time when you add another device, this process of elimination
should single out the telephony device which causes difficulty with your
Internet connection. Bear in mind that since adding a single telephony device
will introduce a piece of equipment, a filter and a line cord into the circuit,
*any one of these things* could introduce a fault into the circuit – be
prepared to swap equipment around and test rigorously.
What is the purpose for doing an Isolation test
If you are having issues with things like your connection dropping out (modem
losing ADSL sync), noise/static on your phone line, slower speeds than usual,
then this test can help isolate the issue.
All these issues are often caused by some form of interference induced into
line, which could be a result of bad filters, dodgy phone cables,
malfunctioning telephony equipment, or even nearby electrical devices. Ensure
that "pest-it" and other electronic rodent repellers (like the devices Dick
Smith and others sell) are removed from power points – these often cause
problems with ADSL signals. The same goes for any electrical equipment capable
of generating an electromagnetic field, such as fridges/freezers, air
conditioners, compressors, cordless phones, microwave ovens, flourescent lights
etc. This alone is a good argument for not using extension cords, as they act
as an antenna for electromagnetic interference induction.
Notes
• If after you have done all this and still having issues, it isn't
always a problem with your line outside your house (Telstra's boundary), it
sometimes could be an issue with your internal wiring (eg a mouse could've
chewed the wires in your roof). Issues can also arise with corroded
cabling/sockets, problems with hardwired equipment that can't be removed (alarm
systems, wallphones, ringer bells), or internal cabling that won't support ADSL
due to faulty installation – the latter is why you try all the sockets.
• If after you have done all this and still having issues, it isn't
always a problem with your line outside your house or your internal wiring. It
may be possible that your modem has gone faulty and would be good if possible
to test with another modem.
If you have completed your isolation tests and still have no ADSL connection,
an unstable connection, or a poor speed issue etc, it's time to escalate the
problem to your ISP and let them launch an investigation for you. It's in your
best interest to complete this process first though for several reasons:
• If the problem is on your end, you can clear it quickly
yourself.
• Your ISP will ask you to do it anyway, both for speed and to
protect you – see point 3 below.
• If a Telstra tech finds the problem is beyond the Telstra
Network Boundary Point (NBP), they not only charge you a large (in the
hundreds) exhorbitant fee, but they leave the problem as is and walk away. This
is because any and all wiring, sockets, equipment and connections
downstream/past the NBP are your privately owned equipment, which Telstra will
not service. Doing your isolation test thoroughly eliminates this as an issue,
protects you from being charged this fee, and allows you to correct any issues
with your own equipment more quickly than waiting for a Telstra tech to do so.
Cheers,
Ronni
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