RE: getting started with web hosting(bandwidth)

[Alan Mead <adm ipat com>]

At 09:34 AM 9/27/00 , Chris S wrote:
> we have a dedicated cable line, i don't think there is anyone sharing it 
> with us.  i do know that the @home business package is totally separate 
> from the regular @home line that people normally get into their homes.  if 
> we wanted to host 100 2page sites with a maximum of 5 images per site, 
> strictly informational(no database requirements), how much bandwidth would 
> we be able to get away with?  would a dedicated business cable line suffice?

I think John is referring to the fact (AFAIK)that cable is a LAN 
technology.  So you share your local bandwidth (the bandwidth from your 
gateway to the cable company's upstream provider) with your 
"neighbors".  Who your neighbors are depends on how they have set thing up, 
I imagine.  I wouldn't be surprised if you are paying more (?) for exactly 
the same service as residential customers.  @Home seems to go out of their 
way to limit residential users, so maybe it won't be too bad.  The thing 
is, as network intensive applications start to crop up and be used more and 
more (e.g., gnutella), your available bandwidth may fluctuate.  I've also 
heard allegations that cable providers don't have enough upstream... So you 
may have great connectivity with the cable office, maybe separate from the 
residential users, but if they don't have large enough lines coming into 
their office, you will have reduced performance.

I think you should try it.  But here's what sucks about cable 
companies:  They aren't ISP's.  Try getting a straight answer out of them 
about this stuff.  Maybe your's is an exception.  But mine has basically 
one guy who knows how to answer questions like this.  And the @Home are as 
bad or worse (they're somewhat separate from the local people).

Oh, about the pages.  You need to count the bytes per page.  I have log 
pages I can access that exceed 2 megabytes.  Those would take a LONG time 
on a dial-up but only a couple minutes on my cable modem.  My area is 
apparently getting the 128K upload limitations someone mentioned and that 
would means it would take many minutes to serve such pages from my 
residential @Home account.  You should look into that.

Here's a sketchy way to figure bandwidth [someone let me know if I'm making 
this up]:

Assume an average and maximum page size.  That's the size of the HTML page 
itself, any junk it loads like images, java, stored JS procedures, 
etc.  Now figure how many page hits you can expect per second (say during 
peak usage).  Multiply the average page size by the number of hits per 
second and that's your bandwidth needs.  (Use the max size by hits as a 
worst case scenario.)  Now figure a 128 kilobit/sec connection will 
transfer about 13 kilobytes per second.   I've observed downloads on my 
@Home connection of 150 KB/sec.  So if you get 100 hits per second (one 
person requests a page from each site each second--this is fairly intense), 
and the average page is 2000 bytes then you would need to transfer 200,000 
bytes per second, which is in the cable modem ballpark.  But if each page 
had a 100K picture, you would need more than 10 MB/s (far more than a cable 
modem) in order to handle things smoothly.  If you have less bandwidth, 
people experience your site as sluggish or even get timed-out.

A closing thought:  Is it bad that your total bandwidth will be equal to 
that of each cable user (or, worse, far less if you have 128K upload 
limits)?  So that several simultaneous cable users could (conceivably) 
swamp your site?

-Alan