Wired Networks CIT 1100 Chapter4
Wired Networks In this chapter you will learn- What a network does Components of a wired network To use a network to share resources
What is a Network? Networks come in many sizes and vary widely in the number of computers attached Connecting two computers in a home to share files and play games creates the smallest network you can have Some companies have thousands of employees in dozens of countries and need to network their computers together to get work done. Typically networks fall into one of two categories: LANs and WANs
Local Area Network A Local Area Network (LAN) covers a small area and contains a modest number of computers LANs are usually contained in a single building or group of nearby buildings Typical LANs include home and school networks
Small Stand-alone local Area network Wide Area Networks A Wide Area Network (WAN) usually covers a large geographic area and can have a substantial number of computers, a WAN is typically composed of two or more LANs connected together Small Stand-alone local Area network Public Network Could grow into a multi-national Wide Area Network
Internet intranets The largest WAN in existence is the Internet, which is a worldwide network that connects billions of computers and networks An intranet, in contrast, is essentially a private network that is a scaled-down version of the Internet for a very specific group of users P 258
Servers and Clients People use two types of computers in networks servers and clients Servers share things such as files, folders, and printers Clients enable you to access those shared things anything that makes requests is a client A computer can act as a server or a client or both Servers manage network resources making them available to the network
Network Classifications Networks are traditionally classified into client-server and peer-to-peer, depending on the role played by each computer in the network In a peer-to-peer network, computers on the network acts as both a client and a server
Networks Networks offer many benefits over standalone computing in several categories: Enhanced communication and collaboration Easier sharing of files and resources Increased personal productivity Lower costs because of the sharing Easier management of machines in the network
Networks A network can make you lose control over your computer, add cost, and cause security problems Users will not always have complete control over there computer settings and software Additional costs for servers, cables, and network cards Administrative costs Problems can interrupt the entire network
Components Connectivity between the PCs and a way to handle communication are handled in one of two ways: Directly connected to a LAN via a cable from the computer to LAN port Wirelessly to the LAN Network clients have a network adapter or network interface card that connects to a central network box called a hub or switch
Network Interface Card NIC provides the physical connection between the Computer and the Network
A Hub or a Switch provides a central connection point Two PCs can be directly connected using a special cable called CROSS-Over cable to create a small Local Area Network When 3 PCs or more need to be connected a different method is needed A Hub or a Switch provides a central connection point The Cross-Over cable is replaced with Straight-Through cables Devices connected to a network that can be addressed separately are referred to as Nodes
Software It takes both hardware and software to make network communication work When computer A requests an file from computer B, the operating system and other software take file and break it into small, individually numbered units called packets The NIC takes the packets and, following the Ethernet standards, wraps up those packets into network frames that get sent out along the cable to the central network hub or switch
Ethernet Ethernet defines electrical signaling as well The Ethernet standard defines everything about modern network hardware Ethernet cables have standard connectors the most commonly used is the RJ-45 connector Ethernet defines electrical signaling as well That way the sending NIC will break data down into little pieces and the receiving NIC will know exactly how to put them back together
Ethernet Most modern Ethernet networks employ one of three technologies: lOBaseT 10 Mbps lOOBaseT 100 Mbps lOOOBaseT 1000 Mbs (1Gbps) All have a distance limitation of 100 meters 100BaseT uses Category 5 (CAT 5) Ethernet cables Gigabit Ethernet runs on Category 6 (CAT 6) Ethernet cables
Duplex and Half-Duplex New NICs run in full-duplex mode, meaning they send and receive data at the same time The vast majority of NICs and Switches use a feature called auto-negotiating to allow very old devices that might attach to the network and need to run in half-duplex mode Half-duplex means that the device can send and receive, but not at the same time, Hubs are half-duplex devices
HomePlug HomePlug (AKA Ethernet over Power) enables you to run a net work signal through the existing power outlets in your home It is not a single product, but a set of industry standards Plug your Ethernet cables into the HomePlug devices, plug the devices into an electrical outlet This is not as fast as the fastest Ethernet (typically 85Mb/s) but it is simple to install
Hubs and Switches Hubs and Switches sit at the very center of networking, handling the tasks of receiving and sending packets of data to the connected computers. Each functions quite differently when they receive an Ethernet frame A hub simply repeats the frame down every network cable connected, hoping one of the computers connected is the recipient machine A hub is not “intelligent” in that it makes no determination where it sends the data
Hubs and Switches Unlike an unintelligent Hub a switch learns the network address of every machine connected to it, reads the recipient address on the frames, and sends them along only on the appropriate node Switches are now much more common than hubs
That’s not addressed to me HUBS Send this frame to PC #3 All Hosts connected to the Hub receive the Frame since it is a shared connection PC One Transmits a Frame Addressed to PC Three 3 One That’s not addressed to me Shared BUS That’s addressed to me 3 3 When one Node on a hub is transmitting others must wait everything is Half-Duplex Only Host 3 Receives it because it has 3s address Three TWO 9/17/2018
Switch Operation Laptop sends document to Printer File Transfer E-MAIL A switch sets up concurrent connections, everything can be sent Full-Duplex File Transfer E-MAIL E-Mail Server Shared Printer 9/17/2018
Using Networks Once you've assembled the pieces for a network, you can access files on a server, print to a shared printer, share files, etc… Two things need to be in place before this all happens All communicating systems must be physically connected to the network Devices, and folders must be shared to be accessible by the network
Using Networks The physical connection has already been explained, the next requirement is to set up Permissions to determine what users are allowed to do: Accessing the file Deleting the file Moving the file Copying the file And more
Share and Set Permissions To share a file on a network – Select Share this Folder Start by locating the file- Click on Advanced Sharing Right Click and select the Folders Properties Click on the Sharing Tab Open Computer Navigate to the folder You could optionally assign a share name that would be displayed on the network or leave it “Pictures” Note If you do not have administrative rights you will be prompted for the password You can specify number of users that can simultaneously access the file
Share and Set Permissions To Set permissions on a the network – Click on Permissions You can Allow or Deny- Full Control – Users can see the contents of a file or folder, change existing files and folders, create new files and folders, and run programs in a folder Change - Users can change existing files and folders, but cannot create new ones Read - Users can see the contents of a folder and open files and folders