Re: Hub or Router?

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Date: Thu, 09 Dec 2004 18:53:55 -0600

Knoppix User wrote:
> Hello Everyone
>
> I am trying to setup some type of a home network. I have three computers
> one "Amd 750 mhz with linux connectiva"
> two "Pentium 166 mhz with windows me (sometime 9x)"
> three "IBM 66DX (not sure if it pentium or what)" with 95 (mostly dos
> games)"
>
> I want all three be able to share files, printer, scanner, and internet. I
> was reading some stuff, and it turns out that hub is only good for file
> sharing and printer.

Not so. The main difference between a Hub and a Switch is that what
data goes in one port (jack) on the Hub is repeated to all other ports
on the hub. They are pretty dumb devices. But the data is the data is
the data, as it were. The services (file sharing protocols like SMB or
FTP or print sharing protocols) don't care about the physical network
between them. They run at a logical level.

A Switch adds some intelligence and looks at the MAC (Ethernet) address
of the data coming in one port and only sends it out the appropriate
port(s). It is better because you get most of your bandwidth.

Say you have a 4-port Hub running 100Mbps with four computers attached.
  If you transfer a large amount of data between computers A and B, they
will use up most the 100Mbps bandwidth for everyone, including computer
C and D's connections. All ports on a hub see the exact same traffic.
A switch would only send data destined for Computer A out computer A's
port, and computer B out computer B's port. Computers C and D would
still have most of their 100Mbps available to them. The switch keeps an
internal table of what devices are on which port according to their MAC
address.

The only traffic that spans all ports on a switch would be the
'broadcast' traffic, used for services that are hunting for things on
the net or announcing stuff to the world, as it were. DHCP is an
example of such a protocol. Your computer "announces" itself and waits
for a DHCP server to reply with an address for your computer to use on
the network. You probably won't need to use that in your home network,
though. Unless one of your computers is a laptop that you sometimes use
on another network, like at work or an Internet coffee shoppe.

Usually you'll see a Switch used in an office where most the ports are
100Mbit to the desktops, and there is a 1Gb port or some other
super-fast port out the back to the rest of the network backbone.

Switches can get pretty fancy and start to do some of the things you
would think a router does. For a home you don't need to get too elaborate.

By the way, a switch is intelligent but not very. It works on the
Ethernet address level, known as the MAC address. This is the lowest
level, and IP protocols ride over Ethernet. Routers actually look
inside the Ethernet frames (chunks of data) and pull out the IP header
information to make routing decisions that are much more advanced than
simple filtering based on MAC addresses. Routers are what makes the
Internet happen.

In fact, routers for the home are pretty cheap. They have all the
advantages of a Switch and then some. Most of them will come with a
built-in firewall and DHCP server. You usually just use your web
browser and point it to your router's IP address to do the
configurations. (Yes, that means it is also a mini web server, but only
for it's management pages - not for your home page).

I would actually recommend this to you. Routers for the home market
pretty much expect a scenario with a few computers and a cable modem, so
they should have instructions to help. But NATCH! They usually only
bother explaining set-up for Windows systems. Ask they guy at the store
to let you look through the manual. Most of these will have 4 or 8
switched ports for the home network and one extra port that is the
'gateway' port where you plug in the cable modem. The router's firewall
(if so equipped) can be set up to restrict and direct traffic between
the two halves (internal and external networks).

>
> My question is what hardware do I need beside network card for sharing
> files, hardware, and internet?
> Aand can I use wireless network card in linux?

Yes, WiFi is supported. Check the distribution to see, as it is a newer
feature with many. If you have particular WiFi NICs (network interface
cards) in mind it is best to research them specifically for
drivers/support by make and model just to be safe. Remember, the WiFi
bandwidth is shared by everyone, like the situation with a Hub. The
physical cables to a port on a Switch each have their own 'pipe' as it were.

>
> Note: I want total 110% Linux to control Incoming and Outgoing traffic
> (server stuff maybe?)...
>
>

If you want to use Linux to control the traffic, you're talking about
setting it up as a firewall and a router. The big gotcha here is that
the Linux box will have to be on all the time for the others to get to
the network. Also, you're talking about putting in a second network
card for the "external" network (the cable modem). Your computer will
also be running software to forward packets between the cards, becoming
a router. All this and you STILL need to buy a switch or hub to connect
the rest of the computers to the Linux box. This is all well and good
and can be very educational. But it will make demands on your Linux box
and require it to be always on. For most home applications a home
router with built in firewall would probably do fine. For added
security you can run 'personal firewalls' on each PC if you so desire.
But I doubt you'll need to.

I hope this is helpful!

Peace,
morningdew

• Previous message: J.O. Aho: "Re: Linux & MSI K8N Neo2 Platinum (nForce3 Ultra) questions..."
• In reply to: Knoppix User: "Hub or Router?"
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