Home Networking A home network generally conforms to one of the following configurations A stand-alone computer connected to the Internet. A peer-to-peer network containing two or more computers with no Internet connectivity A peer-to-peer network containing two or more computers with internet connectivity Physical Requirements Your network may be either hardwired or wireless. Hardwired networks require cabling while wireless networks (ignoring ad hoc networks) require an access point (AP) or a wireless router to interconnect the hosts. No Internet Connectivity Required If no Internet connectivity is required, then a wired network requires only that the we connect the computers on the network together. Of course, every computer needs a network interface card (NIC) which conforms to the technology (token ring, Ethernet, AppleTalk, wireless) you want to use. What follows assumes that Ethernet (802.3)will be the wired technology and that 802.11 will be the wireless technology. If only two computers are to be connected it is only necessary to connect the NIC in one computer to the NIC in the other computer using an Ethernet category 5 twisted pair cable (with 8 wires). It is very important to note that in this configuration the cable must be a crossover cable (sometimes referred to as a null modem cable.) If the computers are separated by a great distance and you don t want to run twisted-pair cable than the NIC cards will have to be wireless and you will need an Access Point or wireless Router to connect the hosts. If multiple computers are to be connected using wired Ethernet than a hub (or a switch or a router) must be used. The NIC card in each computer is connected to the hub using normal CAT 5 twisted pair cable. Wireless connectivity for multiple hosts is the same as for just two hosts. Internet Connectivity Connectivity to the Internet is provided in one of three ways Dial-up This connection requires a telephone modem to connect your computer to the telephone line. Modern computers all have a modem built in so that for a stand-alone computer it is only necessary to run a telephone twisted NTC Oct 28, 2006 Page 1 of 5
pair cable (category 3 with two or four wires) to a telephone outlet; no NIC card is needed. A multiple-host network requires a router to be connected to the telephone outlet and your hosts will connect to the router, either with wired Ethernet cables and NICs or wireless NICs. 1 DSL Cable Digital Subscriber Line is a broadband technology which allows relatively (compared to dial-up) high-speed connection to the Internet. A special modem called a DSL modem is required which is connected directly to a telephone outlet. The other side of the DSL modem is connected to either a stand-alone computer via a category 5 twisted-pair cable and a NIC card, or to a router (wired or wireless) which connects to the hosts on the network as described above. 2 Cable is a broadband technology which allows high-speed (compared to both dial-up and DSL) connectivity to the Internet. A special modem called a Cable modem is required which is connected to your television cable using a splitter 3. The other side of the Cable modem is connected to either a stand-alone computer via Ethernet twisted-pair and a NIC card, or to a router (wired or wireless) which connects to the hosts on the network as described above. Software Requirements Most of the software for setting up a home network is provided by the operating system on the host computers and it is only necessary to configure the hosts appropriately. Three pieces of os software are required: NIC Drivers These small software programs tell the operating system how to communicate with the NIC card. Most operating systems have drivers for the commonly-used NIC cards. If not, the NIC card will have come with the drivers on some media such as a CD-ROM. As a last resort the drivers can be gotten from the manufacturer of the NIC card. The manufacturer provides different drivers for several operating systems and os versions. 1 Note that when the computer is connected to the Internet the telephone line is busy and cannot be used for voice communications except via a microphone connected to the computer. 2 Unlike dial-up, DSL connectivity does not interfere with voice communication via standard handsets which can proceed regardless of whether or not the computer is connected to the Internet. 3 A splitter is a passive device which splits the cable signal coming into your home. It has one input (from the Cable company) and two outputs (one connects to your TV set, the other to your cable modem.) NTC Oct 28, 2006 Page 2 of 5
Redirector Protocol Stack The redirector software is part of the operating system. Its purpose is to examine requests for resources and determine whether the resource request can be satisfied on the local computer or is to be directed to the NIC card and the network. In Windows the redirector is called Client for Microsoft Networks. The protocol stack identifies the protocol(s) to be used by the host machine for communicating with other hosts on the network. For a peer-to-peer LAN which will not be connected to the Internet or any other network via some routing mechanism NetBEUI can be used. Novell NetWare-based LANs will use IPX/SPX for the protocol stack. Hosts on a LAN which will communicate with the Internet will use TCP/IP 4 Network-Aware Applications In general these will be application programs such as your web browser and you email client. Other software may be explicitly required depending on the operating system. For instance, If a machine running Linux is on the same LAN with machines running Windows, than SAMBA will be needed to allow Windows machines to access data on the Linux machine. Multiple Linux machines on a LAN will use NFS to access data on each other s machines. Configuration Configuring Windows [shares as well as tcpip] Configuring Windows requires 1. Specifying the NIC 2. Specifying the Redirector 3. Specifying and configuring the protocol stack Specifying these three components of Windows is done in the properties of the My Network Places folder. Right-clicking on My Network Places opens a window listing the kinds of networks available, including Wireless Network Connection and Local Area Connection. For wired networks, right click on the Local Area Connection and specify the NIC, Redirector and Protocol in the dialog box. When TCP/IP is the specified protocol, Internet. 4 TCP/IP can be, and often is, used on stand-alone LANs even when they do not connect to the NTC Oct 28, 2006 Page 3 of 5
additional configuration is performed by selecting TCP/IP in the dialog box window and clicking the properties button. A new dialog box appears, which has two radio buttons. By default, the radio button labeled Obtain an IP address automatically is selected. If this is left as is, than the IP address for you host will be chosen by your ISP (if you are directly connected to your ISP) or by your router using DHCP. Choosing the other button, Use the following address, allows you to manually specify the IP Address of your host, as well as the IP address of any DNS servers (you don t need to specify this since you will be using your ISP s DNS servers) and gateway address (you set this to the IP address of either your router or your modem.) For wireless networks you also need to configure the wireless NIC or other wireless device attached to you computer 5. Generally there are three things to specify: 1. The Service Set ID (SSID). This is set to match the SSID of your router or access point as specified in that devices documentation. 2. The Channel. A number of channels are available for the access point and your computer over which to communicate with each other. It makes no difference which channel you choose but all computers on your network must use the same channel, usually the default of the access point. 3. The encryption method. The default is usually no encryption, but you should change this by enabling either WEP or WAP encryption. WAP is preferred if both are available. This will cause a password to be required by anyone trying to gain access you your network. The above is all you need do to get connectivity to your LAN and the Internet. However, it is not enough if you want to share files with other computers on the LAN. Any Windows host which wants to allow other Windows hosts to access its folders and files must do two things 1. Enable File and Printer Sharing. This is done in the same place where you specified the NIC, Redirector and protocol stack 2. Share folders and files. Each folder and/or file that you want to permit access to must have sharing enable. Right click on the folder or file and select Sharing and Security.... You can then specify whether sharing is allowed and whether users can write to as well as read the folder/file. If you allow sharing a folder, all subfolders will also be shared, unless you turn off sharing of them individually. Printers can also be shared on a Windows network. There are two ways to share a printer. 5 Such wireless connectivity might be built into your computer, or may be an adapter card plugged into you computers bus, its USB interface, or its PCMCIA card slot. NTC Oct 28, 2006 Page 4 of 5
1. The printer is attached to one of the hosts as is usual for a printer. In this case, the printer is shared in the exact same way a folder is shared: find the printer in the Printers and Faxes section of the Start Menu or Control Panel, right click on it and choose Sharing.... Each of the other hosts on the LAN must install the appropriate printer drivers as if the printer was directly connected to their machines. 2. The printer is connected to a Print Server which is connected directly to the LAN. In this case the printer is seen as another device in My Network Places. The print server instructions will specify how the operating system is to communicate with the printer. NTC Oct 28, 2006 Page 5 of 5