Re: [Hampshire] More on broadband speeds

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Author: Jon Fautley
Date:  
To: Hampshire LUG Discussion List
Subject: Re: [Hampshire] More on broadband speeds

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On Fri, 7 Dec 2007 22:50:30 -0000
"Rob Malpass" <rob@???> wrote:

> There's been a lot of talk on this list this week about speeds, but
> in the process of relocating the modem (and power cycling in the
> process), I've seen the speed halve. Could this be due to power
> cycling the modem - or is it more to do with net speeds will slow
> (even on cable) during the evenings as more folks are using it? I
> don't mind a deceleration in speed in peak hours but for it to fall
> by 50% - quite a drop.


Cable is the worst offender for contention of the connection,
unfortunately.

While ADSL providers (specifically, BT, as that's where 99% of all UK
ADSL comes from) publish their contention ratios (20:1, 50:1, etc),
cable suppliers often don't because it can look so bad.

Cable is essentially a shared Ethernet medium. You, your neighbours and
anyone in your local area is on one big Ethernet segment, connecting
back to the UBR (essentially the termination point) at the exchange or
lurking in a green cabinet near you.

Unfortunately, this means that the more people using the connection,
the worse it gets, in a very noticeable way.

I used to have a 20Mbit NTL/VM cable connection, and during peak times
in the evening I'd notice the speed drop to something in the region of
2Mbit, and sometimes just be unusable. It's just one of the 'features'
of cable, I'm afraid :(

I'd try and do the tests during a quiet period (2am-6am, or failing
that probably around 10am-11am or 2pm-3pm), use the ADSLGuide speed
tester (adslguide.org.uk/tools/speedtest.asp) and perform the test with
the modem in the 'good' position, then immediately move it and try it
in the 'bad' position. It's possible you have a dodgy cable and
moving it around has created a short or just affected the join with the
connector. This should let you know if its contention or a dodgy cable.

Cheers,

/j
-- 
Jon Fautley RHCE, RHCX               email: jfautley@???
Senior Consultant                    cell :     +44 7851 558683
Global Professional Services
Red Hat UK, 200 Fowler Avenue, Farnborough, Hampshire, GU14 7JP