Showing results for 
Search instead for 
Did you mean: 

i'm confused about my adsl 500 speed


i'm confused about my adsl 500 speed

we have a business adsl 500 account.

i run a web server here to serve certain website database requests. i've been trying to implement a bandwidth throttling scheme however using the limited features of the zyxel zywall 10w

when the throttling features are disabled my connection speed using the plusnet speed test is slightly above the recommended adsl 500 speed, according to the table shown after the plusnet speed test.

However as soon as i enable the throttling effect, doing the speed test slows the speed down to 200kbps or 25KB/s
I have tried this several times hoping it was just an anomaly and that a user was downloading a large file or something but this is the case with all other web servers turned off here.

1) What's the difference between kbps and KB/s??

2) The value I entered in the downstream section of the throttling options was about 400 which in theory should limit all downloading traffic (our exchange server, ftp, users web browsing, terminal services, any real audio etc...), except a certain port (591 for our website requests) to a maximum of roughly 400kbps, why would I be getting a significantly lower value from the speed test?

Is there something obvious that I'm missing?
Anyone have any experience with setting up this kind of throttling system? Or any experience with the zyxel zywall 10w?

Community Veteran
Posts: 5,878
Registered: 04-04-2007

i'm confused about my adsl 500 speed

Why do you need to throtle the connection? You kmention going above the 'recomended speed for ADSL 500'. If you have an ADSL 500 account the speed will usually be about 576k mainly because of the overheads on traffic on the BT network.
You don't get charged extra for going above the 500k, it is a physical maximum.

With regards to your first question - bits and bytes. 8 bits make up a byte, data throughput is usually measured in bits.


i'm confused about my adsl 500 speed

So KB/s will be bytes and kbps will be bits?

The reason I need to throttle the traffic is when our exchange server is downloading a particularly large e-mail, any web requests to our database get timed out.
Posts: 182
Registered: 03-08-2007

i'm confused about my adsl 500 speed

Try Netlimiter v1.30, I find it very usefull. Smiley
Community Veteran
Posts: 14,469
Registered: 30-07-2007

i'm confused about my adsl 500 speed

There are multiple PCs involved here I think so it's not possible to limit transfers using a PC based tool like netlimiter. Only the router can do this as it is currently being used.


I have no idea why throttling the download rates would effect the speedtests as much as you are seeing, as they are just download tests.

What happens if you lower the throttle to say 200Kbits/s, does the speed tester show a corresponding decrease again?

Are you running the latest firmware for your router - maybe worth checking if there is a later version which may have some fixes in.

i'm confused about my adsl 500 speed

OK I've worked it out!!!

Turns out LAN to WAN means downstream! I thought it meant upstream.

It's sorted now - bandwidth throttling ago-go!!