The following is a list of the inner workings of a typical network: Network interface cards - NIC, Network cable, Network hub and Network software

The following is a list of the inner workings of a typical network: 

Network interface cards: Inside any computer attached to a network is a special electronic circuit card called a network interface card. The TLA for network interface card is NIC.

Using your network late into the evening is not the same as watching NIC at night. If the network is set up to use that time to update software and back up data, the NIC has to be robust enough to handle all-day-allnight use.

Although it’s also possible to use an external network interface that connects to the computer via the computer’s USB port, most networked computers use a built-in network interface card.

Network cable: The network cable is what physically connects the computers together. It plugs into the network interface card at the back of your computer.

The most common type of network cable looks something like telephone cable. However, appearances can be deceiving. Most phone systems are wired using a lower grade of cable that won’t work for networks. For a computer network, each pair of wires in the cable must be twisted in a

certain way. That’s why this type of cable is called a twisted-pair cable. (Standard phone cable doesn’t do the twist.)

Older networks often use another type of cable, called coaxial cable or just coax. Coax is similar to the cable used to bring Nick at Nite to your TV. The cable used for cable TV is not the same as the cable used for computer networks, though. So don’t try to replace a length of broken network cable with TV cable. It won’t work. Networks require a higher grade of cable than is used for cable TV.

Of the two cable types, twisted-pair cable is the best kind to use for new networks. Coax cable is found in plenty of older networks, but if you are building a new network, use twisted-pair cable. For the complete lowdown on networking cables.

You can do away with network cable by creating a wireless network, though that option has some challenges of its own. For more information about wireless networking.

Network hub: If your network is set up using twisted-pair cable, your network also needs a network hub. A hub is a small box with a bunch of cable connectors. Each computer on the network is connected by cable to the hub. The hub, in turn, connects all the computers to each other. If

your network uses coax cable, the cable goes directly from computer to computer; no network hub is used.

Instead of hubs, most newer networks use a faster device known as a switch. The term hub is often used to refer to both true hubs and switches.

Network software: Of course, the software really makes the network work. To make any network work, a whole bunch of software has to be set up just right. For peer-to-peer networking with Windows, you have to play with the Control Panel to get networking to work. And network operating systems such as Windows Server 2003 or Novell’s NetWare require a substantial amount of tweaking to get them to work just right. For more information about choosing which network software to use for your network. To find out what you need to know to configure the software so that your network runs smoothly.

The NOS Choice - Network Operating System Choice

The NOS Choice

Most dedicated network servers do not run a desktop version of Windows (such as Windows XP, ME, or 98). Instead, they usually run a network operating system (NOS) designed to efficiently carry out the tasks that coordinate access to shared network resources among the network client computers.

Although you have several network operating systems to choose from, the two most popular are NetWare and Windows 2000 Server. Here’s a bird’s-eye view of what’s out there:

-  One of the most popular network operating systems is NetWare, from a company called Novell. NetWare is very advanced but also very complicated. So complicated, in fact, that it has an intensive certification program that rivals the bar exam. The lucky ones that pass the test are awarded the coveted title Certified Novell Engineer, or CNE, and a lifetime supply of pocket protectors. Fortunately, a CNE is really required only for large networks to which dozens (even hundreds) of computers are attached. Building a NetWare network with just a few computers isn’t too difficult.

-  Microsoft makes a special server version of its popular Windows operating system. The latest and greatest version is called Windows Server 2003. Its predecessor, Windows 2000 Server, is still widely used. In addition, many networks still use an even older version called Windows NT Server. (Throughout this book, I’ll use the term Windows Server to refer to the various server versions of Windows.) Not wanting to be left out, Microsoft has its own certification program for Windows server specialists. If you pass the full battery of certification tests, you get to wear an MCSE badge, which lets the whole world know that you are a Microsoft Certified Systems Engineer.

- Other network-operating-system choices include Unix and Linux. Apple also makes its own network server operating system called Mac OS X Server, designed specially for Macintosh computers.

Dedicated Servers and Peers

Dedicated Servers and Peers

In some networks, a server computer is a server computer and nothing else. It’s dedicated to the sole task of providing shared resources, such as hard drives and printers, to be accessed by the network client computers. Such a server is referred to as a dedicated server because it can perform no other task besides network services.

Other networks take an alternative approach, enabling any computer on the network to function as both a client and a server. Thus, any computer can share its printers and hard drives with other computers on the network. And while a computer is working as a server, you can still use that same computer for other functions such as word processing. This type of network is called a peer-to-peer network, because all the computers are thought of as peers, or equals.

Servers and Clients

Servers and Clients

The network computer that contains the hard drives, printers, and other resources that are shared with other network computers is called a server. This term comes up repeatedly, so you have to remember it. Write it on the  back of your left hand.

Any computer that’s not a server is called a client. You have to remember this term, too. Write it on the back of your right hand. 

Only two kinds of computers are on a network: servers and clients.

Computer Networking: few basic buzzwords

Computer Networking:  few basic buzzwords

- Networks are often called LANs. LAN is an acronym that stands for local area network.

- Every computer connected to the network is said to be on the network. The technical term (which you can forget) for a computer that’s on the network is a node.

- When a computer is turned on and can access the network, the computer is said to be online. When a computer can’t access the network, it’s offline. A computer can be offline for several reasons. The computer can be turned off, the user may have disabled the network connection, the computer may be broken, the cable that connects it to the network can be unplugged, or a wad of gum can be jammed into the disk drive.

- When a computer is turned on and working properly, it’s said to be up. When a computer is turned off, broken, or being serviced, it’s said to be down. Turning off a computer is sometimes called taking it down. Turning it back on is sometimes called bringing it up.

What Is a Network?

What Is a Network?

A network is nothing more than two or more computers connected by a cable (or in some cases, by a wireless connection) so that they can exchange information.

Doing Backup from Hiren’s Boot CD 15.1

Doing Backup from Hiren’s Boot CD 15.1:

1    1.       System On
2.       Press F12 for Boot options
3.       Select the “Change Boot Mode Setting” options to the Cd Drive ,
4.       Boot mode is set to: UEFI; Secure boot: ON ….. Window Appears.
5.       Select  “Legacy Boot Mode, Secure Boot Off”
6.       (Note: Default Boot mode is set to: UEFI; Secure boot: ON)
7.       Warning: Do u want to Change --- Select Ok or Cancel.
8.       Select again F12 and Select Cd/DVD device in LEGACY OPTION.
9.       Select Windows 7 Portable
10.   Win 7 Loaded and Hiren’s Boot CD 15.1 – Program Launcher Window appears.
11.   Get the Backup Drive and get connected.
12.   Select Programs – Backup –Norton Ghost -Ghost Normal
13.   Cmd line and Symantec ghost 11.5.1 window appears. Click ok
14.   Select Local – Partition  – To Image
15.   It asks for mount click yes

Airtel 3G Dongle Data Card Customer Care Number Toll Free Number:

Airtel 3G Dongle Data Card Customer Care Number Toll Free Number:

Airtel 3g Data Card customer generally facing problem with Airtel 3g Data Card concerning slow connection speed, Wrong billing, frequent disconnection. So you essential to complain to Airtel 3g Data Card customer care immediately concerning your problem, Below we provide the all particulars of Airtel 3g Data Card Helpdesk customer care number.Airtel 3g data cards in postpaid and prepaid customer care numbers and service toll free numbers are maintain below.

A 3G USB modem (dongle or data card) is device that permits you to wirelessly connect to internet using a GSM/CDMA network and delivers you the aptitude to surf the Internet on extremely high speeds.

Airtel 3G Data Card Toll free number: 18001030405

Airtel Customer Care Number: 1800-103-4444 (Toll-Free).

Airtel portability toll free number: 18001031111

Airtel 3G Technical Hotline (Customer Care) - 12118

Contact Airtel Customer Care Executive: Dial 121 followed by 9.

What is the after sales service available for airtel 3G USB modems

Each customer for query, complain or support can contact toll free number 18001030405

What are the types of airtel 3G USB modems available? 

With the launch of 3G, airtel has recently launched 2 types of airtel 3G USB modems in the marketplace. These are a) 3.6 Mbps & b) 7.2 Mbps For additional information on them & specifications please refer to the division types of airtel 3G USB Dongole /modems.airtel/Huawei customer service support post deals for all airtel 3G USB modems sold.

Airtel 3G Data Card Customer Care Numbers in India:

Airtel 3G Data Card Customer Care Number DELHI 9871427070
Airtel 3G Data Card Customer Care Number KARNATAKA / BANGALORE 9845907070
Airtel 3G Data Card Customer Care Number ANDHRA PRADESH / HYDERABAD 9866007070
Airtel 3G Data Card Customer Care Number MUMBAI 9892307070
Airtel 3G Data Card Customer Care Number PUNJAB 9872007070
Airtel 3G Data Card Customer Care Number CHENNAI 9840007070
Airtel 3G Data Card Customer Care Number KOLKATA 9831717070
Airtel 3G Data Card Customer Care Number MAHARASHTRA / PUNE & GOA 9890107070
Airtel 3G Data Card Customer Care Number GUJARAT 9898547070
Airtel 3G Data Card Customer Care Number TAMIL NADU 9894407070
Airtel 3G Data Card Customer Care Number KERALA 9895377070
Airtel 3G Data Card Customer Care Number UP WEST 9897137070
Airtel 3G Data Card Customer Care Number MADHYA PRADESH 9893327070
Airtel 3G Data Card Customer Care Number HARYANA 9896407070
Airtel 3G Data Card Customer Care Number HIMACHAL PRADESH 9816107070
Airtel 3G Data Card Customer Care Number RAJASTHAN 9829207070

Airtel 3G Data Card Customer Care Email Address For Complain Online:adcsupport@airtelindia.com

Airtel Data Card HelpLine Number:  Call to 7070 from your Airtel handset.

Connecting to the Internet - Dialup connection, Network connection, IP addressing, Sharing an Internet connection

Connecting to the Internet

The process used to connect to the Internet relies on the connection configuration of a PC using either a dialup or network to connect. After the connection is made, the process is the same and the same protocols are in use.

Dialup connection

Dial-up Networking has a built-in dialer that invokes the necessary commands to the modem to dial the modems of the service provider and make a connection whenever an application, such as a browser or an e-mail client, is opened. The speed of a dialup connection is typically between 28.8 Kbps and 56 Kbps.

Remember Dial-up networking uses PPP to send data packets over telephone lines. PPP picks up a packet that has been created by one of the other network protocols and which will be received by a remote PC running that same protocol. PPP is merely the intermediary that carries the data packet over the telephone line. If the packet begins the journey as a TCP/IP packet, it arrives at its destination as a TCP/IP packet.

An ISP typically assigns an IP address to PC though its NAS (network access services), or modem banks, and RADIUS (Remote Authentication Dial-In User Service) services, after a username and password combination is verified and the user is authenticated.

If a dialup connection will not connect, check the following areas:

l Remember Phone connection: Nearly all modems use sound to enable the user to track the action of the connection (handshake) as it is being made. The first of these sounds is the dial tone from the phone line. If the modem is not connecting and you do not hear a dial tone, there is a problem with the wall jack connection or the phone line itself. Chances are that you will get an error message to the effect of no dial tone anyway.

l Modem problems: If the modem cannot complete the handshake with the other end, the modem might be configured incorrectly in terms of its character length, start and stop bits, and speed.

l Protocols: Another common problem, especially for new modems, is that TCP/IP or other protocols have not been properly configured. Dialup connections typically require the PPP protocol. Verify that the protocols are enabled and that the proper bindings are set for the protocols.

l Remote response: The NAS you are attempting to connect to might be down or having problems. Call the ISP to check.

l Telephone company problems: If there is sufficient static or crosstalk on the telephone line, it can cause the modem to disconnect very soon after completing the connection or cause enough data retransmissions that the line appears exceptionally slow.

Network connection

If a PC connects to the Internet through its LAN, its primary (or default) gateway is the router on the LAN that is used to connect to the WAN (Internet). The only real differences between establishing a dialup connection and a network connection is that the network connection remains in place and does not require a reconnection each time access is desired, and the user does not need to be authenticated except for secure services, such as e-mail or VPN (virtual private network).

IP addressing

IP addresses are four sets of numbers separated by periods (dots). An IP address is 32 bits long with each of the four numbers 8 bits long. The highest possible IP address is 255.255.255.255, because the highest value that can be represented in 8 bits is 255. Each of the four numbers is called an octet, which means a set of 8, and are referred to as the first, second, third, and fourth octets. Sounds a little like a singing group--the Octets and their new hit "Home, Home on the Domain."

IP addresses can be assigned as a static IP address (a fixed PC location) or as a dynamically assigned IP address (changeable). A static IP address is permanently assigned to a node when it is added to the network. Static IP addresses work as long as the network doesn't move, the NIC card is not interchanged with other PCs, or the network is never reconfigured. If a network will be reconfigured, however, it should use dynamically assigned IP addresses. Each time the PC is booted, the Dynamic Host Configuration Protocol (DHCP) server assigns it an IP address to use for that session. All versions of Windows 9 x and Windows NT, and Windows 2000 have built-in DHCP clients.

Sharing an Internet connection

Internet Connection Sharing (ICS) is a feature included in Windows 98 SE and Windows 2000 Professional that allows home and small office users to share a single Internet connection. The type of connection isn't important, ICS assumes a network to be present and isn't fussy about the type of network or the media used.

ICS builds a type of LAN with one PC serving as the network gateway. The other PCs on the network use the gateway PC to connect to the Internet. The requirements are that each PC be connected to the gateway via a network connection and that a single modem, proxy server, DSL, ISDN, or other Internet connection line serves the entire network.

Installing and configuring a browser

Installing and configuring a browser

If you were to search the Web for "configuring a browser," and I did, you will find a long list of resources to help you configure a browser for everything from chat session tools, graphic tools, Telnet, and much more. Today's most popular browsers, Internet Explorer (www.microsoft.com), Netscape Navigator (http://home.netscape.com), and Opera (www.opera.com), are largely self-configuring.

However, there are some areas where the configuration of the browser can affect the PC on which it is loaded. Here are the ones you should know for the exam:

l Cached content: To speed up the time required to display a downloaded Web page, browsers store the page and its objects in a disk cache on the hard disk. Internet Explorer (IE) calls this Temporary Internet Files. When you ask to see the page again, it is supplied from the cache, which speeds up the display and reduces the amount of bandwidth required to support your PC.

By default the cache is emptied each time IE is started. However, you can change the caching settings so that the cache is never cleared, a page is never cached, or some setting in-between. One of the more important of the caching settings is the amount of the disk space you wish to assign to cache. If you have all the disk space in the world, then you can use more of the disk for caching, but if the PC is low on disk space, minimize the disk space used for Internet caching.

l History files: The History folder holds the addresses and links to sites you have visited on the Internet over a given time period. These links are displayed in the drop-down list of the Address line of the browser. Keeping a fewer number of days reduces the amount of disk space used for these links.

l Players and handlers: The latest releases of the most popular browsers include most of the players and handlers required for the majority of content on the Web. However, you may want to download customer players and handlers to display or playback the content on specific Web sites.

The popular players and handlers are Adobe Acrobat (used to read PDF [portable data format] files), Flash (used to play Macromedia Flash animations), and Windows Media Player, Apple QuickTime, and RealPlayer (all used to play back streaming audio, video, and multimedia).

Keeping your finger on the network pulse - IPConfig, PING, TRACERT

Keeping your finger on the network pulse

Windows 9 x and Windows 2000 include a number of network monitoring and diagnostics tools that are used to troubleshoot and isolate network problems that directly affect a single PC. Here are the ones you should know for the exams:

l IPConfig (IP Configuration): This command line utility displays the current configuration for a PC connected to a TCP/IP network.

l PING (Packet Internet Groper): This Internet utility is used to determine whether an IP address is online or reachable. Either an IP address or a domain name can be pinged over a network.

l TRACERT (Trace Route): This TCP/IP utility is used to determine the path in use between one network point and another and if any problems exist along that path.

Sharing print and file services

Sharing print and file services

After a PC is configured as a part of a network, the user can grant other users on the network access to folders, files, or devices on the PC. Some minor dangers exist in sharing files, such as unknowingly sharing a virus across the network or others using your disk to save large files that would fill up their disk. However, this is an excellent way to avoid printing or copying files onto a disk in order to share a file or to share the wealth of that nifty new color laser printer you bought for yourself.

To set up file and printer sharing on a PC, follow these steps:

1. Double-click the Networks icon on the Control Panel.

2. Click the File and Printer Sharing button.

3. Select (place a check in the box) the option or both options you wish to enable. Your choices are "I want to be able to give others access to my files" and "I want to be able to allow others to print on my printer(s)." Notice the careful wording in these options. Just because you enable the options doesn't mean that all of your files and printers are immediately available to the world. You still need to grant permission and set up passwords.

4. Click OK a couple of times to close the boxes and restart the PC.

Sharing files

At this point, the File and Printer Sharing services are loaded, but nothing is really shared.

To share files with other users on the network, use the following steps:

1. From the Windows Explorer, right-click any folder. Only folders can be shared. So, if you don't want to share all of the files in a folder, you'd better move the files you don't want to share to an unshared folder. Choose Sharing and complete the level of sharing and security you want for this folder. You may assign a password to read-only or to full-access levels of sharing.

2. Any share you create will appear on the Network Neighborhood under the PC's Computer Name, which is the name specified on the Identification tab of the Network properties window (the one opened from the Network icon on the Control Panel). If you want a more descriptive name, change it.

Sharing a printer

Here are the steps used to share a printer:

1. Open the Printers folder from either the Setting menu or the Control Panel.

2. Right-click the printer to be shared and choose Properties to display the properties window for the printer. Choose the Sharing tab.

3. On the Sharing tab, enter the share name of the printer and a password if you want to control who has access to the printer. Click OK.

4. The printer will not appear on the Network Neighborhood under the PC's name.

Instant Answer If you click the Network Neighborhood icon and no PCs are shown, check to see that you have enabled printer and file sharing and that other PCs on the network have also set up resources to be shared.

Configuring a PC (NIC) for a Network

Configuring a PC (NIC) for a Network

1. Click the Start ® Settings ® Control Panel.

2. From the Control Panel, double-click the Networks icon to open the Network window,

An alternative path to the Network window is right-clicking the Network Neighborhood icon and choosing Properties.

3. On the Configuration tab, double-click the adapter to open the Properties window for the NIC.

The Driver Type tab should indicate an Enhanced mode (32-bit and 16-bit) NDIS (Network Device Interface Specification) driver for the NIC. The other choices are for cards without 32-bit NDIS support or NICs requiring ODI (Open Data-Link Interface).

On the Bindings tab, you'll find a list of the protocols and services for which a binding is established. In most cases the bindings are preconfigured, but they can be modified. Binding is a network term for two protocols that perform different networking functions that have an active connection. If you are on an Ethernet network that has access to the Internet, your bindings will reflect your NIC card with a binding to TCP/IP protocols.

The contents of the Advanced tab vary by NIC and the characteristics of the network. The properties list may reflect the media and connector in use or it may be used to turn on a log file.

4. Click any Apply or OK buttons that appear.

You are asked for other network information, IP address, gateway, and DNS. The user or the network administrator should provide this information. The system will update its information database, and you may be asked to restart the system.

Modem facts you should know

Dialing up a network

Modems don't hold the vaulted position on the Core Hardware exam they have in the past, but expect to see questions on the exam about installing, configuring, and troubleshooting a modem, both internal and external.

Modem facts you should know

A modem (which is an acronym for modulator/demodulator) converts the digital data signal of the PC into the analogy data signal used on the plain old telephone system (POTS), which is also called the public telephone switched network (PTSN). Modems can be installed inside the PC in an expansion slot or attached to the PC externally through a serial or USB port.

You may hear or have heard of modems for other types of communications besides dialing into a network, such as an ISDN (Integrated Services Digital Network) modem or a DSL (Digital Subscriber Line) modem.

Modem types

The two general types of modems are the following:

l Standard modem: A standard modem can be an internal or external device. It can also be Plug and Play or legacy. Standard modems are operating system neutral and use generic device drivers.

l Windows modem: A Windows modem is an internal Plug and Play device that requires a device driver provided by the Windows operating system to function properly.

The best way to differentiate one type of modem from another is by reading the documentation that came with the system or visiting the manufacturer's Web site.

Internal versus external modems

An internal modem is installed like any other expansion card--into a compatible expansion slot. Modern modems do not require physical configuration, but some have DIP switches or jumpers to be set. Most of the configuration of the modem is done through the operating system.

Modems use serial communications modes. Be sure to read up on flow control and full- and half-duplexing.

Protocols and other niceties

Protocols and other niceties

In addition to the three network protocols described earlier in this chapter (Ethernet, token ring, and
FDDI), other protocols can be used to interconnect PCs to other PCs or networks.

Connecting a workstation to the network and Addressing protocols and services - DHCP, DNS, WINS

Connecting a workstation to the network

Each network topology is associated with a network technology or protocol. Ethernet networking is the most common on a bus topology, and Token Ring is the most common on a ring structure.

The network technology in use is important because when you connect a PC to the network for the first time, you need to know the network identity requirements for a new workstation.

Addressing the network

The three addressing elements used on a network that you should know are

l MAC (media access control) address: Every NIC or network adapter is assigned a unique-tothe-world ID (called the MAC address) by its manufacturer when it is made. This address is burned into its firmware and cannot be changed. The MAC address is the basis for all network addressing and all other address types are cross-referenced to it. A MAC address is a 48-bit address that is expressed as 12 hexadecimal digits (4 bits to a hex digit). WINIPCFG command display showing the MAC address (Adapter address) of a NIC, which in this case is 44-45-53-54-00-00.

Tip To display this box on a Windows PC, enter WINIPCFG in the Start Run box.

l Remember IP (Internet protocol) address: Many internal and all external networks use IP addresses to identify nodes on both LANs and WANs. An IP address for a network workstation combines the address of the network and the node into a 32-bit address that is expressed in four 8- bit octets (which means sets of eight). Figure 22-3 shows the results of the IPCONFIG command that displays the IP addressing information for a workstation. To run this command, open a command prompt and enter IPCONFIG on the command line.

The IPCONFIG command is used to display the IP address configuration of a PC.

IPCONFIG displays the IP address assigned to the workstation (in this case, 192.168.1.100), its subnet mask (which is used to determine which part of the network the workstation is located), and the default gateway of the node.

l Network names: The most common form of a network name is the share name assigned to a workstation and is used to identify it to other network users who want to share its resources over the LAN. The most common network name used on a Windows network is the NetBIOS (Network Basis Input/Output System) name, which is a unique 15-character name that is periodically broadcasted over the network so that the Network Neighbor-hood function can catalog them. The NetBIOS name is the one that shows up on the Windows Network Neighborhood.

Addressing protocols and services

Many protocols and services can be used on a network to aid in the correlation and translation of one address form to another.

The ones you need to know for the A+ exam are the following:

l DHCP (Dynamic Host Configuration Protocol): This is a protocol used to automatically configure a network workstation with its IP address data. Each time the workstation is logged on to the network, the DHCP server software, running on a network server or router, assigns or renews the IP configuration of the workstation. Typically, the address assigned is from blocks of IP addresses that have been set aside for use by internal networks. Depending on the network operating system, IPCONFIG or WINIPCFG can be used to view, renew, or release DHCP data.

l DNS (Domain Name System): DNS is used to resolve (translate) Internet names to their IP address equivalents. For example, when you request www.hungryminds.com from your browser's location line, a nearby DNS server (typically at your ISP), converts it to an IP address, such as 12.168.1.100, which is then used to request the data across the Internet.

l WINS (Windows Internet Naming Service): WINS is Microsoft's network name resolution software that converts NetBIOS names to IP addresses. Windows machines are assigned NetBIOS names (see "Addressing the network" earlier in this section), which are converted into IP addresses for use on a network using TCP/IP (Transmission Control Protocol/ Internet Protocol), the foundation protocol suite of the Internet. The use of a WINS server allows nodes on one LAN segment to find nodes on other LAN segments by name.

Connecting to an Ethernet network

When a new workstation is added to an Ethernet network, it identifies itself using its MAC address and computer name to the rest of the network. Those devices that need to hold this addressing information, such as a switch or bridge, store it in their MAC address tables. When requests come in for a particular IP address, the MAC address of the node is looked up and the message is sent to that workstation.

Before you bury me in e-mails, please understand that this is highly simplified, but represents the essence of what happens.

Connecting to a Token Ring network

When you add a new node to a Token Ring network, it must establish first that its address is unique. The workstation sends out test frames with its ID address and the system responds with its own test frames sent to that address. If no other node responds (oops), the new ID address is accepted and established for the new ring node. If there is duplication (it can happen), jumpers or DIP switches on the NIC can be used to alter the address.

Just call me NIC

Just call me NIC

The network interface card (NIC), also known as a network adapter, is central to the concepts of networking covered on the A+ exams.

The NIC is a physical and logical link for a PC to a network. It is installed inside the computer in an open expansion slot. NICs are available for most of the expansion bus architectures, so getting a card for an available slot is easy. However, the most common bus used for NICs is the PCI (Peripheral Component Interconnect), but many legacy ISA (industry standard architecture) cards are still in use.

Tip When choosing a NIC for a system, try to get one that is Plug and Play (PnP) compatible to make setup easier. Even with PnP, a network card can be a pain to set up. Some NICs use DIP switches or jumpers, and some use software to configure its identity and compatibility to the network.

The setup needed for the NIC is controlled by two factors: the PC itself and the NOS (network operating system, such as Windows NT/2000 or Novell NetWare). If you have the choice, do yourself a big favor and use the same brand and model NIC in every PC on the network. Mixing NICs on a network can be a pain, and you know where.

The NIC is a translator that works between the network and the PC. Networks transmit data in a serial data format (one bit at a time), and the data bus of the PC moves data in a parallel format (eight bits at a time). The NIC acts as a go-between to convert the signal from serial-to-parallel or parallel-to-serial, depending on its direction. The NIC also formats the data as required by the network architecture.

The NIC attaches a PC or other networked device to the network cabling and the network system. The primary purposes of the NIC are to serve as a transceiver, a device that transmits and receives data to and from other NICs (installed in the other networked nodes and devices), and to connect to the network cabling.

Here are a few NIC characteristics you should know:

l MAC (Media Access Control) address: Each NIC is physically encoded with a unique identifying address that is used to locate it on the network. This address is 48 bits (6 bytes) long.

l System resources: A NIC is configured to the computer with an IRQ, an I/O address, and a DMA channel. A NIC commonly uses IRQ3, IRQ5, or IRQ10, and an I/O address of 300h.

l Data bus compatibility: NICs are designed with compatibility to a particular data bus architecture. ISA (Industry Standard Architecture) and PCI (Peripheral Components Interconnect) cards are the most common.

l Data speed: The NIC card must be compatible to the data speed of the network. The data transfer speeds of a network are determined by several factors, including the cable media, the topology, and the network connectivity devices in use. For example, a token ring network uses STP cable-- the workstations attach to the network through MAUs (Multi-station Access Units)--and typically runs at either 4Mbps or 16Mbps. An Ethernet network uses UTP cable (or coax), attaches its workstations through hubs or switches, and most commonly runs at either 10Mbps or 100Mbps.

Many NICs have the ability to sense the data speed in use. A NIC designated as a 10/100 NIC has the ability to autosense between a 10Mbps and a 100Mbps network.

l Connectors: Several different connectors are used to connect NICs to network cabling. The type of connector depends mostly on the type of cable in use. Coax cabling primarily uses a BNC (for which they are several alleged meanings, none of which you need to know for the A+ exams) connector. Fiber-optic cabling is rarely used for cabling to workstations because of its cost. The most commonly used connector for networking is the RJ-45 connector, which is very much like the connector on your telephone, only a little bigger.

Passing around the signals

Passing around the signals

Here are descriptions of the networking terms you may encounter on the A+ exams. These devices play a key role in the performance of the network. You don't need to memorize them, but understand how they're used.

l Repeater: An electronic echo machine that has no other function other than to retransmit whatever it hears, literally in one ear and out the other. A repeater is used to extend the signal distance of the cable by regenerating the signal.

l Hub: Used to connect workstations and peripheral devices to the network. Each workstation or device is plugged in to one of the hub's ports. A hub receives a signal from one port and passes it on to all of its other ports and therefore to the device or workstation attached to the port. For example, if an eight-port hub receives a signal on port 4, it immediately passes the signal to ports 1, 2, 3, 5, 6, 7, and 8. Hubs are common to Ethernet networks.

l Bridge: Used to connect two different LANs or two similar network segments to make them operate as though they were one network. The bridge builds a bridging table of physical device addresses that is used to determine the correct bridging or MAC (Media Access Control) destination for a message. Because a bridge sends messages only to the part of the network on which the destination node exists, the overall effect of a bridge on a network is reduced network traffic and a reduction of message bottlenecks.

l Router: Routes data across networks using the logical or network address of a message to determine the path it should take to arrive at its destination.

Remember Too many workstations broadcasting too many messages to the whole network causes a broadcast storm. A router helps prevent broadcast storms by routing messages only to certain segments of the network.

l Switch: A switch is a device that segments a network. The primary difference between a hub and a switch is that a switch does not broadcast incoming messages to all ports, but instead sends it out only to the port on which the addressee workstation exists based o a MAC table created by listening to the nodes on the network.

l Gateway: A combination of hardware and software that enables two networks with different protocols to communicate with one another. A gateway is usually a dedicated server on a network because it typically requires large amounts of system resources.

Three different types of gateways exist:

¡ Address gateway: Connects networks with different directory structures and file management techniques.

¡ Protocol gateway: Connects networks that use different protocols. This is the most common type of gateway.

¡ Format gateway: Connects networks using different data format schemes, for example, one using the American Standard Code for Information Interchange (ASCII) and another using Extended Binary-Coded Decimal Interchange Code (EBCDIC).

A network devices primer

A network devices primer

The Core Hardware exam focuses on the hardware used to connect a PC to a network, which boils down to the network interface card (NIC) and the cabling to which it attaches. Other hardware devices are used on a network to improve its performance or to provide an interface between different types of networks, and you should at least review these for background.

Cabling the network

In order for one computer to carry on a conversation with another computer, both computers must be able to transmit and receive electrical impulses representing commands or data. The computers and peripherals of a network are interconnected with a transmission medium to enable data exchange and resource sharing. Cable media has laid the foundation on which networks grew--literally.

Tip Although near and dear to my heart, wireless networks are not included on the A+ exams.

Primarily three types of cabling are used on most networks:

l Coaxial (coax) cable: Similar to the cable used to connect your TV set to the cable television service. Two types of coaxial cable are used on networks: thick coaxial cable (commonly called 10Base5, thickwire, or thicknet) and thin coaxial cable (10Base2, thinwire, or thinnet).

l Twisted pair (no, not the upstairs neighbors) cable: Available in two types: unshielded twisted pair (UTP) and shielded twisted pair (STP). UTP, which is by far the most commonly used network cabling, is similar to the wiring used to connect your telephone.

For use in networks, unshielded twisted pair (UTP) is clearly the most commonly used. UTP is referred to in many different ways: 10BaseT or 100BaseT, Cat 3 or Cat 5, or simply as Ethernet wire. These all translate loosely to "The moon is made of green iMacs," but they all refer to copper twisted pair wiring.

Time Shaver You may encounter some terminology relating to twisted pair copper wiring on the exams. Don't worry too much about the really technical issues surrounding each term.

l Fiber-optic cable: Glass or polymer fibers carry modulated pulses of light to represent digital data signals. Although a few different types of fiber-optic cables exist, you care about only one specific kind, and it's generally referred to as fiber-optic. Fiber-optic is also known as 10BaseF or 100BaseF.

Server and Server Types

Hello, I'll be your server

Several types of servers can exist on a network, each one performing a different task for the network and its workstations. A server is usually thought of as a computer, but a server is actually the software that performs, controls, or coordinates a service or resource. One computer can physically house many different software servers. To network clients, each server can appear to be a completely separate device, when that is not usually the case. lists the most common types of servers implemented on a network.

Server Types