Network for Small Office

7/31/2019 Network for Small Office

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How to set up a network for Small Office /

Home Office Computers

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This overview will help you set up a network for two or more computers in your SmallOffice / Home Office (SOHO).

Many people are unaware of how easy and inexpensive it is to interconnect existingcomputers to form a small Local Area Network (LAN). If you are using Windows 98/XP,

no additional software is required to enjoy basic network functions such as shared use ofdirectories, drives, or printers and the hardware costs are minimal. A network cansubstantially simplify internet access for two or more people. Of course another reason forsetting up a network is to play multiplayer games such as Quake or use "groupware"applications such as shared calendars, contact lists, todo lists, etc.

Configuring and connecting networking hardware

The standard networking technology is Ethernet. Ethernet works by means of adaptersknown as Network Interface Cards (NICs) in each computer. The NICs are connected withcables which vary depending on the cabling option chosen. Many recent computers have

built-in (motherboard) network capability.

Ethernet comes in two flavors. Fast Ethernet operates at 100 Megabits per second (Mbps)and is overkill for a SOHO. Regular or original Ethernet operates at 10 Mbps which is fastenough for a small LAN. NICs can be purchased to fit into an EISA card slot or a PCI slotand can also be found to fit a laptop PCMCIA slot.

There are two different Ethernet cabling options one of which will be usually used in anygiven LAN. NICs can be purchased with any of these interface connectors or even with twoconnectors. If the NIC has more than one connector a jumper plug or softwareconfiguration is usually used to select which connector is in use. NICs cost as little as $20

each.

The coax interface, also known as 10-base-2, or "thin", or "BNC" Ethernet works with acoaxial bayonet "BNC" connector on the NIC. Computers are connected together in a"daisy chain" using BNC "T" adapters plugged into each NIC. A coaxial 50 ohm cableconnects each "T" to the "T" on the next computer. The first and last computers will have aterminator resistor plugged into the unoccupied arm of the "T". Coax is only available in10 megabit speed. Hubs and NICs that provide coax are harder to find.
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The twisted pair interface, also known as "UTP" or 10-base-T or "RJ-45" has an RJ-45 jackon the NIC. The RJ-45 connectors look similar to the standard telephone RJ-11 jack (butare somewhat larger) and are used with cables that look similar to standard telephonetwisted pair cables to connect the NICs to a "hub", high speed modem, or router. The hubhas between 4 and 32 RJ-45 jacks. New office buildings are sometimes wired with RJ-45

jacks in the walls to facilitate setting up 10-base-T LANs. Hubs plug into a power line andcost $60 and up. Some hubs provide a BNC connector as well as the RJ-45 jacks. Motelsare increasingly providing RJ-45 connections for laptops.

The coax 10-base-2 approach is simpler since no hub is required. Larger LANs almostuniversally use 10-base-T because in-wall wiring is neater and the network is not disruptedby someone connecting or disconnecting their computer. Routers and newer computers thatcome with Ethernet capability usually use 10-base-T.

Setting up network software

Ethernet transmits data by means of packets and automatically adjusts to addition ofcomputers to a net. NICs all have a unique address built in at the factory to facilitate this.After you physically install your NIC you will need to install the driver for the NIC usingWindows 98/XP installation procedures and diskette supplied by your NIC manufacturer.Usually, diagnostic software and software to set up the NIC regarding which connector touse (if it has more than one) is also supplied. Many NICs emulate the grandfather of allNICs the NE2000 in case you inherit some no-name NICs with no drivers.

Once you install the driver you will go to the Windows control panel and select Networkswhich is organized as clients, adapters, protocols, services, and file and print sharing. Makesure that client for Microsoft networks, your adapter, Microsoft IPX/SPX compatible

protocol, and Microsoft file and printer sharing for Microsoft networks service areinstalled. Under file and print sharing check "give others access to my file" and "giveothers access to my printers".

When the network is completed you can specify specific drives or directories to be sharedwith other computers on your LAN under "sharing" which will appear under the pull-down"file" menu. You can share individual directories or entire drives for read-only access oraccess with a password. You can also specify printers to be shared. When directories,drives, or devices are shared you will see a hand symbol attached to the icon for that item.

Protocols are formats and procedures for transfer of data. The IPX protocol (originally

developed by Novell) is used by many applications programs including games such asDuke Nukem 3D.

Groupware

Although you can share files so that any computer on the LAN can open the same file onthe same drive there is a complication in that if more than one computer tries to open andchange the same file simultaneously the changes from one person will be lost. Many


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applications such as Microsoft Word will not open a file that is already open on someoneelses computer. Applications specifically designed for collaboration ("groupware" or"work group applications") avoid this problem.

Email is the ultimate "poor mans" groupware application since you can accomplish many

group functions such as adding to or modifying other peoples text, setting up meetings,etc. using email, especially if you have a more sophisticated email client such as Eudora.

Peer and Server Networks

Networks of computers all of which are used as work stations are commonly known as"peer" networks. A server network requires an additional dedicated server machine, usuallyrunning expensive "server" software and therefore may be less attractive in a SOHOcontext. When investigating groupware applications make sure to understand if a serverand specific server software is required or if the application can run on a peer network.

How to set up a TCP/IP network

You may want set up a local network for the Internet protocol TCP/IP (in addition to IPX)to allow use of applications which use TCP/IP and TCP/IP only games like Quake on yournetwork. In addition you may want to set up TCP/IP to allow computers on your LAN toaccess the Internet as described below. To do this set up the TCP/IP protocol in Windows98/XP networking and bind it to your Ethernet adapter. Each computer on the LAN needsto have its own address. The addresses in the ranges 10.10.10.0 to 10.10.10.255 and192.168.0.0 to 192.168.0.255 have been reserved for local networks so no site on theInternet will have addresses in these ranges. Therefore you should give each computer onyour LAN a different address within this range such as 10.10.10.1, 10.10.10.2, etc. Dont

use 10.10.10.0 or 10.10.10.255 as these have special uses. Set the network mask to255.255.255.0 on each computer. You may be able to use the network connection wizardto automatically set up your network.

Connecting your local network to the Internet

You can set up a modem on one of your computers under dial up networking to access anInternet Service Provider (ISP) such as IBM.net or sprynet.com even though you have alocal TCP/IP network set up. The computer will automatically go to your local network foraddresses in the 10.10.10.X range and to your dial up network for other addresses. Butwhat if you want employees on any of your computers to have access to the Internet for

email and other applications? This can be done as follows:

ISPs generally provide a single Internet Protocol (IP) address to their low-cost dial-upcustomers. This IP address is usually assigned dynamically at logon time so that it can bereassigned to someone else when you log off. ISPs also usually only allow one person tolog on at a time under a single account so even if you have multiple phone lines andmodems you would need multiple ISP accounts to allow two or more people simultaneousinternet access. There are a number of software products such as Trumpet Firesock ( see


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"connectivity products" at www.tucows.com or www.cws.com ) which allow multiplecomputers on a LAN to use a single ISP account simultaneously. These programs use "IPspoofing" to make multiple users look like a single user to your ISP. The modem andconnectivity product are installed on one of your computers. The TCP protocol in all thecomputers is set so that the address of the connectivity computer (eg 10.10.10.1) is set as

the gateway. All the computers are set to use the Domain Name Server address (DNS)specified by the ISP. The connectivity product can be set to automatically dial and connectto the ISP whenever anyone tries to access any internet service outside your LAN anddisconnect after a predetermined time elapses with no access. The "connectivity computer"would need to be left on whenever anyone might need access. Alternately a stand-alone"router" can be used to connect between your LAN and the internet via dial-up modem,high speed access, or ISDN line.

You can usually connect multiple computers to a network that also includes a cable modemor DSL modem to allow all the computers Internet access. However, cable and DSLaccounts also typically charge more for multiple computer access to the Internet. If you

have two NIC cards in a connectivity computer you can connect one to your cable modemand the other to your in-house network linking to other computers. Windows XP willnearly automatically set up both sides of this arrangement (no additional connectivityproduct needed) such that the cable or DSL modem thinks it is only talking to one user.You only pay the single user charge while your other computers can access the Internet viathe connectivity computer. You may also be able to use a single NIC to connect to yourinternal network and use a USB cable to connect to the cable or DSL modem, avoiding asecond NIC. Inexpensive router boxes can be used to connect a single modem to multiplecomputers.

Cable and DSL "always on" services normally semi-permanently assign an IP address and

name to your account. This can haveprivacy implications.

Voice Over IP Services

Inexpensive router boxes are now available to support voice over IP (VOIP) servicesprovided by Vonage or other Internet based telephone service. These units connect to theInternet via RJ-45 cable connecting to your cable or DSL modem and typically provide twoRJ-11 phone connectors and three RJ-45 ethernet connectors. The ethernet connectors canbe connected directly to up to three computers. The phone connectors can be connected toordinary phones or fax machines to provide up to two lines of phone service. The phonelines can be routed to many phones via standard building phone lines. However, thesesmall VOIP boxes may not be able to drive as many ringers as a typical telephone companyline. If you are using more than one phone or fax machine on each line, check with the boxvendor to see how many phones each line can handle.

The quality of the VOIP service is mostly dependent on the quality of the underlyingInternet service. For example, if you are having problems with Vonage it is more likelythat the actual problem is with your cable or DSL supplier. If you are using a separaterouter (e.g. wireless router) the VOIP box should be connected to the modem and the router
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connected to the VOIP box. This way the VOIP box will have priority over the computer'saccess and voice quality will be better during times when your computers are accessing theInternet.

Be advised that fax machines typically do not work well with VOIP. This is because any

momentary delay, slowdown, or dropped packets, which do not cause any problem with thecomputer Internet connection, and only cause a click on the voice line, can interfere withthe operation of the analog modem in the fax causing a dropped fax error. If you arehaving problems faxing, try setting the fax's modem to operate at a slower speed (2400baud) instead of the normal 14,400 baud. If the fax's instruction manual does not say howto do this (they frequently do not), try searching on the Internet. Unfortunately, if it workstoday it still might not work tomorrow when if the Internet is busier.

Many people report they are totally unable to obtain reliable fax operation through VOIP.It is futile to look to the VOIP service for a solution and your Internet provider is likely toblame the VOIP provider. An obvious solution that eliminates the need to even have a fax

machine is to have capability for receiving faxes as an email attachment and for sendingfaxes from a scanned or PDF document file uploaded to the VOIP provider. This wouldallow you to send and receive faxes at your laptop in the field as well as at your SOHO andalso allows you to store faxes on your hard drive as opposed to paper file. For someunknown reason, Vonage does not provide this capability although they do provide thecapability for receiving voice mail messages as email attached audio files.

Dynamic Host Configuration Protocol (DHCP)

All the participating devices (computers, routers, etc) in an Internet network need certainconfiguration data to operate including the Internet Protocol (IP) address to be used by the

device, IP address of the upstream gateway, mask defining the size of the local network,and nameserver addresses. Modern software and hardware can use DHCP to get thisinformation automatically from the upstream side at startup and avoid the need for manualentry. However, you need to initialize the boxes in a particular order for this to work. If youfirst turn on the cable or DSL modem, the modem will get its information from thecompany. Then you can turn on your router box, which will get its information from themodem. Then turn on computers so they can get their configuration data from the routerbox. If power fails frequently in your area you may want to use a small uninterruptiblepower supply (UPS). to power the modem and router boxes to avoid having to go throughthis sequence later.

Using ISDN with a local network

If you live in an area which provides Integrated Services Digital Network (ISDN) atreasonable rates such as the Southern part of Bell Atlantics service area you may want toconsider using ISDN vs a modem and analog line to provide Internet connectivity to aLAN. See Using ISDN. ISDN is being replaced with DSL or cable high speed Internetaccess.
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Wireless

Inexpensive wireless routers are now available that connect to a cable or DSL modem andprovide a local wireless Internet "hot spot" in addition to providing typically three RJ-45connections for wired service. Modern laptops typically come with built-in wireless

capability. Small wireless adapters that plug into a USB port can be used to connect adesktop machine to the wireless network. Wireless typically has more "glitches" than wiredand may be somewhat slower, so if a computer is semi-permanently in the same room asthe router, use a wired connection.

Typical Small Office Network with Internet Capability

Here is a description of a typical Internet enabled small office network for a small company"SmallCo":

Five PC type computers running Windows 98/XP are connected via NICs to an Ethernet

using 10-base-T RJ-45 wiring and an 8 port hub. PCs are configured to use TCP/IPprotocol and to use file and printer sharing over the IPX/SPX protocol so all employees canuse all the printers and can use a common file areas or drives on the PCs. A stand-alonerouter is used to connect to the Internet via DSL, cable, or analog modem using an Internetaccess provider and single user account. The company, has a web site at www.smallco.comhosted elsewhere by an ISP or web site developer. (Some DSL and cable providers objectto users running web sites from their DSL or cable accounts.) Each employee has an emailaddress such as [email protected], [email protected], etc. The web site providerfurnishes POP email mail boxes for each employee. Alternately, the web site provider cansupply aliases to route mail from "[email protected]" to an access provider mail box suchas "[email protected]". Email clients on the employee computers access the POP mail

boxes to receive mail and send mail via an access provider SMTP server. See Mail Noteforreturn address considerations.

Managing Modems and Routers

Cable modems, DSL modems, and routers usually have a built-in web server that displaysadministrative pages. By entering the proper numerical IP address in your browser, youcan contact this web server and configure the operation of the device. Modems alsousually display diagnostic information including incoming signal strength, etc. Thisinformation is very useful when talking to your provider about any problem. Modems,routers, and your individual computers all can be configured to act as firewalls. This can

cause confusion if, for example, you are trying to alter the firewall to allow some newservice.

Verizon Fiber Optic Services (FIOS)

In some areas Verizon is offering new high-speed fiber optic Internet services. Fiber is anextremely high bandwidth technology and can carry cable TV services, voice phoneservice, and high speed Internet on a single fiber. The fiber comes to your house and
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connects to a box usually located inside near where the (usually outside) telephoneinterface box is located. If you sign up for fiber Internet you will also get your phoneservice via fiber. This is a benefit to Verizon because fiber is easier to maintain than thePlain Old Telephone System (POTS) copper wires and they already have to maintain thefiber. The interface box has a battery backup so phone service can be provided in event of

a power failure. The battery is reportedly only good for several hours so you may want toconsider other arrangements if you tend to have long outages.

Unlike DSL and cable Internet, which can use wiring normally already installed in thehouse, the user needs to provide an ethernet cable from the fiber interface box to hiscomputer location.

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