Hi,

Just wanting to check my calculations here. Want to be sure I don't have this wrong.

OK..some folks rent dedicated or managed servers on a 1 mbps basis. They mention this works out to just over 300 GB per month. OK, I can buy that.

What I'm wondering about is, since 1024 bits per second only equals 128 bytes per second, I'm thinking this equates with only being able to serve up three web pages per second if the web pages were, on average, 42 KB each in size.

Is this correct? If so, I'm thinking a reseller with a server or account like this would find their customers could easily have slow response times. If such a box had 200 domains on it, request would take a while to get served down the wire or "pipe" to the various browsers making request on this server.

I've heard about bandwidth being "burstable". Not sure how this fits in or works. Don't think I have a good understanding on how bandwidth is sold/allocated/capped at this point in time; please help clarify, if you would. Thanks!

I'm thinking if the limit is so much per second, it seems the amount of theoretical bandwidth in gigabytes per month doesn't limit you so much as the number of request per second -- and that's limited to 128 kilobytes (or three 42 KB pages) per second.

Also, at this limit, I would think a very modest server could quite easily saturate your alloted network bandwidth.

Similarly, if my math is correct, the "unmetered 10 mbps" deals would cap your server to delivering around 30 request per second using a 42 KB average page size. Is this correct?


My math as follows:

1024 mega bits per second =
128 kilobytes per second;

Since there are 60 seconds per minute,
and 60 minutes per hour,
and 24 hours in a day,
using 30 days for a month,
one multiplies as follows:
60 times 60 times 24 times 30 =
2,592,000 seconds per month

multiplying 2,592,000 by 128 KB,
we get 331,776,000 KB per month or 331 GB/month.

Moreover, if folks are dialing in on 56 kbps lines, each of these 42 KB pages would take about 6 seconds to download, at best, if my math is correct. Add to this a "queue time" of waiting for the request to be served down the "pipe" on a 1 mbps or 128 KB/second "pipe" at busy times, and a server with 200 domains on it, and say 35 simultaneous users, would appear to be quite slow.

Even with simple static pages a server which could theoretically dish out at around 1000 request per second would be limited in actuality by the bandwidth "pipe" to only serving around three request per second. Is this correct?


Thanks,

Louis

Would someone care to respond?

Thanks,

Louis

1 megabit/second is roughly 130kilobytes per second yes.
a T-1 is 1.544mbit and will do about 180k per second.

Yes 130 or so K per second isn't really that fast for a server. I see more than a handful of spikes in my bandwidth graphs over 200 K per s.

Most hosts buy by the megabit but have burstable pipes and pay on the 95%.

This means you can have short periods where you're kicking out a lot more than the megabits you're buying, but the top 5% of your spikes are "chopped off" and you're billed for your remaining peak.

Personally, I prefer to buy my bandwidth by the gig transferred but no one locally does that so I buy by the mbit.

Hi Dixiesys,

Thank you very much for your reply! I've got a lot to learn and appreciate your sharing.


Thanks again,

Louis

Three pages per second (at your calc of 42kb pages) is quite a bit over a month's time period though...

3pg/sec * 60sec/min * 60min/hr * 24hr/day * ~30day/month ~= 7.78 million page views

More hits than my webpages get =]

Yes, your calculation is correct. But this is assumed that the connection is being capped. This solution is only well assuming you have 3 pages being loaded every second, a consistent loading. But the fact is that you will not get everything averaged out, so, a burstable connection is preferred with the bandwidth used being aggregated up monthly.