Chapter 3Online Lesson Albert Huang
Network Technology • Network Nodes • Network nodes are devices on the network. Each of these devices provide a specific function for the network, network users and administrators.
Nodes on the Network • Computers • This includes workstations used by network users or servers • Servers are computers that serve other computers or users. Typical servers include: file servers, print servers, media servers, etc. • Network Printers • Allow network users to share the printing service
Nodes on the Network • Network Storage Devices • Such as NAS – Network Attached Storage • Such as a shared DVD drive
Network Media • Network media provide the connections between the nodes. • Network media allow the transmission of data between network nodes • Media category: • Wired • Wireless
Network Media • Copper wires
Network Media • Coaxial Cables
Network Media • Wireless • Radio wave • e.g., AM/FM radio networks • Micro wave – • e.g., WIFI • Infrared wave • e.g., TV remote control • There are computer networks that use infrared wave to avoid EMI, in settings such as power plants.
Network Media • Waves are different in lengths and frequencies
Network Connection Device • Devices that allow multiple cables or wireless channels to connect and perform high-speed interchange of data
Network Connection Device • Switch • Allow incoming data to be transmitted to only cables connected to the destination node. • It is normally used within an organization. • For example, the ESB Computer lab has 32 computers connected to a switch. • The switch is then connected to the campus backbone (high bandwidth cable that connect the different buildings on campus)
Network Connection Device • Routers - a device that directs network traffic, based on IP (Internet Protocol) addresses. It is the fundamental building block of the Internet. • Routers are used between two networks on the Internet • Routers select the most efficient route for the incoming data to be transmitted to the destination nodes
Network Structure • Networks can be organized as • Client-Server • Peer-to-Peer
Client-Server Network • On a client-server network • There are computers configured as “servers” • Servers provide services to other computers • Server services include: network management, file storage, application programs, printing service, web services, and others. • Computers that receive services from the servers are “clients” • A computer can server as a server and client at the same time
Client-Server Network • For example, when you log into a computer on campus, the ID and password is sent to the network management server where they are verified. If the ID and password were correct, the login would be successful. • An example of a file server is the U: drive – where users may store files on a central location. • A client server network could have multiple servers serving different functions.
Peer-to-Peer Network • Networks where most of the computers operate as both clients and servers are called peer-to-peer networks. There is not a central server on a P2P network. • For example, on a P2P network, there is not a network management server that manage the users (IDs and passwords). • Example of a P2P network: • Connecting an iPad and a computer together to exchange files. • Connecting 2 or more devices together using Bluetooth to exchange files. • Connecting multiple computers together using a home router.
Peer-to-Peer Network • A hub is a device that allow multiple cables to be plugged in for connection. Incoming traffics (data) are broadcasted to all nodes.
Internet Protocols • Protocols: communication standards • Internet Protocol is TCP/IP – Transmission Control Protocol/Internet Protocol • Currently, most computers are using IP V4. Many networks are starting to use IP V6.
IP V4 • An example of an IP V4 address • 22.214.171.124
Domain Name Systems • A system that convert a domain name into an IP address to help find the resource. • For example, when you type UOP’s domain name uop.edu on a browser, the domain name is sent to the DNS server and converted to the IP address of the computer that hosts UOP’s web site. The IP address is then used to find the computer and retrieve the web pages from it.
Find the IP address for a Domain • Try the followings on WHOIS.NET • Search UOP.EDU • Search PACIFIC.EDU • Go to http://ip-lookup.net/domain.php • Search UOP.EDU and PACIFIC.EDU
Major Wireless Standards • Bluetooth: • It has a range of 10-30 feet and a maximum bandwidth of 1 mbps. • WiFi • Wireless Fidelity - a wireless standard (802.11) that provides a theoretical bandwidth of 54 Mbps, with a range of up to several hundred feet. Mostly used at homes or offices. • 4G • WiMax • WiMaxis a relatively new technology that is designed to transfer wireless data over relatively long distances. A broadband wireless access. (approximately 30 - 40 Mbps) • LTE (approximately 75 Mbps)
Intranet • It is an Internet-like network built for internal use only. • You may browse a company’s internal Web site, send internal email, and perform other Internet functions. • Intranet is not accessible by outsiders. • Advantage: private and secure. It uses the same technology used on the Internet. Users and technicians do not need to learn a different technology. Hardware and software are available easily.
Extranet • Similar to the Intranet, except it is built for several organizations. For example, an extranet may be built for your company, your suppliers, and your clients. • Users in these organization can browse your extranet sites that are not available to outsiders.
Hosting of Web Servers • Where to put your Web resources? • In-house: maintain both the hardware and software inside your organization. • Hosting: store your Web site on a vendor’s Web server. The vendor takes care of the hardware and server software maintenance. You maintain the data and documents. • Co-location: maintain and own your hardware and software; but store the entire systems on a vendor’s facilities. Vendor provides the space, power, air conditioning, and a high-speed connection.
Hosting & Co-Location • http://Goddady.Com • http://www.1and1.com • http://www.svcolo.com/index.php