Re: ISDN connection

[Mitch Blevins <mblevin@debian.org>]

ivan wrote:
> Hello All,
> 
> Myself and a group of friends wish to connect to WWW by using a permanent
> connection but if we all have 33.6K modems and are all connected then it
> seems that we require at least a 512K connection which is prohibitively
> expensive !
> 
> Question 1.  Is the calculation: <number of possible users> = <permanent
> speed> div <users connection speed> correct ? (ie. 512K / 33.6K = 15.238...
> users)
> - I imagined that a high speed connection such as 512K would support 1000
> users not just 15 !

You are making the assumption that all users would be downloading at
exactly the same time.  Most of your time spent on the web is spent
actually reading what you've just downloading, during which time the
connection is idle and others can use that bandwidth.

> Question 2.  If we do not intend to host our own web pages on our computer
> do we need to use a web server such as Apache ?  If not, what is the
> mechanism for accessing the web through a single computer ?

Don't need Apache.
There are two methods by which this is done.
1) IP Masquerading:  One computer is connected to the Net and forwards
   all IP traffic back-and-forth transparently.  This is probably your
   best solution.

2) A proxy server like Squid:  It will act as a Web Server to all the
   computers on your local net.  When you request a web page, it will
   fetch it and then forward it to the requesting machine.  The
   advantage of this is that it will cache the pages and if several
   users on your local net request the same Web page, it only needs
   to fetch it from the Net once.  The disadvantage is that it will
   only work for protocols like http and ftp, and not for other
   stuff.

You can use both solutions together to get the advantages of each.

> Question 3.  If we use Apache (or other server software), how does it work
> ???  I mean, does Apache request the page from the remote server, download
> to its own memory at, say, 512K and then send to the user at 33.6K or are
> all requests done at the speed of the user so that 15 users as calculated
> in question 1 is correct ?

Although Apache can be set up to be used as a Proxy Server, Squid is
much better.  How it works:
Apache/Squid will download the page form the Net at 512K and store it in
memory or on disk.  It will send it to your computer at the speed of the
local network connection (10Mb or 100Mb).  If the page is in the cache,
it will work at the speed of the local net (really fast), if it has to
fetch it from the 512K line, it will work at that speed (still pretty fast).

Hope this helps,
-Mitch