[CQ-Contest] Cable modem questions

Mon Mar 11 10:04:24 EST 2002

As I said before, you might WANT to use a router for performance reasons,
but it is not NEEDED for functional reasons.  That statement remains
correct.

In fact in Bob's original question where he just wants to hook up a SECOND
computer, no hub or router is needed at all.  A simple crossover cable can
be used to connect the two computers. A crossover cable is an ethernet cable
that is analogous to the null modem for serial port direct connections.
It's available prewired in many lengths at your local computer toy store.
If you use a crossover cable, you therefore must use the Internet Connection
Sharing (ICS) component of Windows as described below.  Aside from that
special case of a 2-computer LAN...

The term router is unfortunately being used in this thread to mean several
things.  One thing it means is that IP packets that are flowing between
computers on your LAN are sent to the router (in the center of a star
configuration) and that router box sends it only to the target LAN computer.
A hub, as was mentioned by someone else, simply passes that packet around to
everyone, and the computer addressed by the packet is the only one to act on
it.  Thus a router will save LAN traffic and make the LAN more efficient.
This matters when you plan heavy traffic on the LAN, such as disk backups
across computers in the face of other LAN activity and the like.  If what
you're doing is normal internet traffic and sending files to be printed,
this level of performance is not needed IMO.  A typical broadband speed is
on the order of 1Mbps.  The slowest LAN is 10Mbps, with most being 100Mbps.
Lots of headroom.

Another use of the term router, but in my view not a proper one, is the act
of "routing" IP packets to a single ISP-provided internet connection from
multiple computers on your LAN, without having to have multiple
accounts/IDs/IP-addresses from your ISP.  I prefer to call this a gateway
function, instead of a routing function.

Here you have a gateway, either hardware or software, that looks to the ISP
as the box that logged on, and that gateway box in turn manages the routing
of packets from the different computers in such a way that the ISP always
sees them as coming from one IP-address.  Internally, it knows how to route
the packets, inbound and outbound, from that gateway to individual computers
on the LAN.

This gateway "routing" function can be done EITHER by a router or by
software in one of the computers.  Windows 98, 98SE, XP, 2000 and probably
NT (I'm not sure of NT) all provide a component called ICS-internet
connection sharing.  With ICS you can have your gateway computer, usually
the fastest, connected to your ISP, and the other computers get their
packets routed to the internet by ICS within the LAN.  The connected
computers are totally transparent to whether they are talking to your ISP
via the ICS gateway, or whether you decided, for example, to bring up a
local-to-that-computer dialup connection, or even a 2nd local broadband
connection.  The LAN-attached computer will preferentially use the local
connection if it exists, or the LAN-gateway connection, otherwise.  This
works like a charm; I've been using it in a 4-computer LAN for a few years
now, with a mix of Win95, Win98SE and WinXP systems.  I have never had a
piece of software that could tell the difference as to whether it was
directly attached to my ISP or attached via a LAN+Gateway/ICS computer.

With the software ICS gateway approach you can also use internal modems on
that gateway machine, although it appears most broadband modems today seem
to be gravitating toward external modem boxes that are ethernet attached, so
this is likely a  limited advantage.

With the external modem you can therefore either ethernet attach it to your
router box, to a hub (instead of a router), or as I prefer to do, to a
separate ethernet card in the gateway computer.  This has the advantage of
having no direct hardware connection between your internet connection and
your LAN, something I prefer for security reasons.  Thus, your gateway has 2
ethernet cards. Your modem connects to one, and the other goes to whatever
LAN hardware you decide to use:  10base2/BNC, hub, or router.  Of course the
LAN-attached computers each have one ethernet card, which connects to the
LAN (10base2/BNC, hub or router on the other end), something independent of
how you connect the modem.

Regardless of which LAN wiring solution you choose, with an always-on
broadband connection you need to invest in some security software such as
zone alarm or Norton's Internet Security.  Both are frequently updated and
monitor traffic to spot typical hacker attempts.  This is like having an
antivirus product to catch viruses before they infest your computer. With a
long-lived connection, it's a prime target for a..holes who like to do dirt.
Some routers, such as Linksys, advertise security inherent in the router.  I
distrust relying solely on the firmware in a piece of hardware to keep
hackers out.  I prefer using software that can be updated frequently (like
weekly), by a company whose business it is to provide hacker security.  So,
even if I had a router, which ostensibly offered some level of security, I
would back that up with a good software security product.

Hope this helped someone. My fingers are pooped.

73,

Gary W2CS

> -----Original Message-----
> From: cq-contest-admin at contesting.com
> [mailto:cq-contest-admin at contesting.com]On Behalf Of Jim Reisert AD1C
> Sent: Monday, March 11, 2002 7:40 AM
> To: cq-contest at contesting.com
> Subject: RE: [CQ-Contest] Cable modem questions
>
>
> At 07:09 PM 3/10/2002 -0500, Gary J. Ferdinand W2CS wrote:
>
> >First of all, you do not NEED a router. You might decide it's the best
> >option, but it's not necessary.
>
> I've been down these roads.  You need to check with your Internet
> provider,
> a router may indeed be necessary. For example, AT&T Broadband charges an
> additional fee ($9.95/month) to connect more than 1 computer (up to 3
> actually) to the Internet (they call it Home Networking).  Using
> a router,
> I can connect as many computers as I want without paying the
> additional fee
> (they see the router as a single computer).  You can set up a gateway
> computer and a hub and do the same thing, but then it needs 2 network
> cards, must always be on, some software like AOL might not work
> through it,
> etc.
>
> 73 - Jim AD1C
>
>
> --
> Jim Reisert AD1C, 7 Charlemont Court, North Chelmsford, MA 01863
> USA +978-251-9933, <jjreisert at alum.mit.edu>, http://www.ad1c.com
>
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