Routers: Do I need one?

Chris wrote:
 > Do I need a router or can i plug in my cable modem directly to my hub and share
 > the internet access that way?
 >
 > What is the point of a router anyways?
 >
 > Thanks
 > Chris

There are three common ways to share an internet connection using a
cable or DSL modem. For a 3-PC setup, these look like:

1. Cable/DSL<==>Modem<==>Hub/Sw<==>PC-1 ; each PC plugs into a
<==>PC-2 ; LAN or downlink port of
<==>PC-3 ; the Hub or Switch, and
; the Modem uses the WAN or
; uplink port

2. Cable/DSL<==>Modem<==>PC-host<==>Hub/Sw<==>PC-client1
<==>PC-client2

3. Cable/DSL<==>Modem<==>Router<==>PC-1 ; each PC plugs into a
<==>PC-2 ; LAN or downlink port of
<==>PC-3 ; the router, and
; the Modem uses the WAN port

(1) gives each PC a direct connection to the 'net, but it requires
the ISP to issue a different IP address to each PC. Many ISPs
charge extra for multiple IPs. Also, those different IPs may
not be in the same subnet, so the PCs may not be able to easily
share files or printers.

(2) requires one PC (PC-host) to perform software routing (using ICS,
which is part of XP, 98SE, and ME) for the client PCs. Free, but
the client PCs cannot get to the 'net unless PC-host is running,
so this configuration is not as robust as (3). If there is only
one client PC, a crossover cable may be used instead of a hub or
switch; a crossover cable is equivalent to a passive two-node hub.
Note that the host PC must have two NICs: one on the WAN-side to
the Modem, and one on the LAN-side to the hub or switch.

(3) uses hardware-routing; a router is cheap but not free. A router
is usually more robust than a solution based on ICS because it
runs a simpler OS than Windows and because it is dedicated instead
of shared with other Windows apps.

--
Cheers, Bob<!-- ~MESSAGE_AFTER~ -->
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