Date: Jun 24, 2001
Category: Networking
Author(s): JackMDS

This long story does not cater to the Professional "Plumbers", so take it easy and let the Newbies get some lead into the "Magic".

The following is mainly relevant to people who use Windows of different flavors.

Step One – No Internet yet Just network.

This is Important, you must have a functional network before you can share Internet connection.

When we have two or more computers, that we would like to connect together, we need some center to move the traffic between them; the simplest device that does it is a HUB.

Hub is a simple device, it has no differentiation capacity, and it is running all the info to all computers. To make the Hub more efficient a Switch was "invented".

Switch is like a Hub that can organize the traffic between the computers, it sends the info only to the Intended computer. The result is more efficient network traffic.

A few Computers connected to a Hub/Switch is called LAN (Local Area Network).

A Corporation has a LAN in one office, and a LAN in another office, they want the two LANs to talk one to the other, so they connect the two LANs with a Router, this process creates a WAN (Wide Area Network).

Router - A device which moves network data from one segment of a network to another. Routers are also responsible for determining where data needs to go in order to reach its destination. Routers can "learn" these paths and more easily send data to its destination. (http://www.hub-tech.net/terms.html).

To move info throughout the system we need to identify the individual computers, so each computer has a name (Computer name), and each LAN has name (Workgroup name).

To move the info we also need Software Protocols. A big number of protocols are available, some of them are just an outcome of "Manufactures Pride", i.e. each big player (Novel, Microsoft, IBM, etc.) develops its own protocol. Some has functional differences. Members of this board will find themselves mainly using three protocols.

TCP/IP – The protocol preferred by the Internet, and a lot of new network games.

NetBEUI – a simple general network protocol that is not functional through the Internet, and thus add some security to internal LAN.

IPX – protocol that is necessary to play some old games over Network.

These three protocols can be installed together. The trick is to bind TCP/IP only as a Client to Microsoft Networks, and to bind the File, and Printer Sharing only to NetBEUI. Doing so decrease the probability of your files been world wide available through the Internet.

TCP/IP needs more then Workgroup Name and Computer name, each computer need an IP number. Some times, we want certain computers to have a fix number, but in most cases, it does not matter what is the number. The "nice" computer companies developed for us a system called DHCP which is a "trick" that the IP numbers are assigned automatically, and the DHCP server keep a track of it. Using DHCP save us the task of entering, and keep a track of the 192.168.123.xxx type of numbers for each computer

All of the above is Network stuff that must be installed regardless of the Internet connection. It must function correctly before you connect to the Internet

Now comes the Internet, and Broad Band Service (Cable/DSL).

The following pertains to External Cable/DSL Modems. If you have an Internal Cable/DSL Modem, you are "out of luck", and sharing is a more complex story.

The providers bring a signal that includes "The Internet", to your home (or office). Devices called "Cable Modem", or "DSL Modem", take the Internet signal and "filters - demodulates" it from the Cable, or Telephone line, to provide Ethernet signal in TCP/IP protocol (it comes out of RJ45 connector).

If we have only one computer, this signal is fed into the NIC of the computer, and End of Story.

However, if we have a Network then the story get more complicated.
Now we are in the WAN business (One Network the Internet, the second Network our own).

The Internet signal has to be fed into our Hub/Switch to be shared with all the network computers. However Hub/Switch (been somewhat dumb) do not know how the distribute the signal to the right computer, a function called NAT.

NAT - Network Address Translation, an Internet standard that enables a local-area network (LAN) to use one set of IP addresses for internal traffic and a second set of addresses for external traffic. A NAT box located where the LAN meets the Internet makes all necessary IP address translations.

(http://www.practicallynetworked.com/sharing/newtothis.htm#NAT)

Microsoft (and some other software manufactures) provided us with a software solution to the NAT, and this software (ICS- comes with Win98SE) has to be used when the Internet signal is fed into a regular Hub/Switch.http://www.practicallynetworked.com/sharing/ics/ics.htm

From a theoretical, point of view this suppose to be the simple end, however there is some functional consideration.

Most Cable provider use the MAC number of the NIC that is installed on your computer as a mean of authentication, at the moment that we move the connection from a single computer to the Hub/Switch the Cable companies read the new number, and will shut down your service. Some Cable companies will agree to change the number to the new MAC of the Hub/Switch, most of them will attempt to charge more if you use a network, and will give you more IP numbers to be use by the additional computers.

Most DSL provider don't care if you share, but they use PPPOE protocol for authentication, a regular Switch is not PPPOE compatible.

Few Network oriented Computer companies saw a niche in the market and came with a new product.

Cable/DSL Router. (SMC, D-Link, Linksys, Cisco, and others).

Most of these products provide a comprehensive solution for all of the above.

They are a combo of Hub/Switch, Router, DHCP, NAT, and PPPOE compatible. In addition they have the capacity to clone your MAC number (so the Router shows to the Internet service the same number as your main computer), and Hardware Firewall protection. Some has additional connection for a Modem, and a Printer Server.

All of these goodies come with a price of $80 to $100, probably the best-valued hardware available to network lovers.

And to paraphrase a member of this board, "Gets you to the 21st Century"

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