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Networking and Support Systems. Business and Computer Technology II. The Home Computer of Tomorrow !!. What is Computer Networking ?. Networking is the practice of linking computing devices together with hardware and software that supports data communications across these devices.
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Networking and Support Systems Business and Computer Technology II
What is Computer Networking ? • Networking is the practice of linking computing devices together with hardware and software that supports data communications across these devices.
Why Do We Use Networks ? • To share information with each other • To share computing devices and peripherals • To save costs for both hardware and software
Basic Types of Networks - Architecture • One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:
LAN – Local Area Network • A LAN connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings.
A Very Simple LAN – P2P • This diagram above illustrates the simplest possible kind of computer network. In a simple network, two computers (or other networkable devices) make a direct connection with each and communicate over a wire or cable. Simple networks like this have existed for decades. A common use for these networks is file sharing.
The Typical LAN • This diagram illustrates a typical local area network (LAN) environment. Local area networks often feature a group of computers located in a home, school, or part of an office building. Like a simple network, computers on a LAN share files and printers. Computers on one LAN can also can share connections with other LANs and with the Internet.
Other Types of “Localized” Area Networks • Metropolitan Area Network - a network spanning a physical area larger than a LAN but smaller than a WAN, such as a city. A MAN is typically owned an operated by a single entity such as a government body or large corporation. • Campus Area Network - a network spanning multiple LANs but smaller than a MAN, such as on a university or local business campus. • Wireless Local Area Network - a LAN based on WiFi wireless network technology • Storage Area Network - connects servers to data storage devices through a technology like Fibre Channel • System Area Network - links high-performance computers with high-speed connections in a cluster configuration. Also known as Cluster Area Network.
WAN – Wide Area Network • A WAN spans a large geographic area, such as a state, province or country. WANs often connect multiple smaller networks, such as local area networks (LANs) or metro area networks (MANs). • A WAN is formed by linking LANs together. For example, several major LANs in a city can connect together forming a WAN. • WANs generally utilize different and much more expensive networking equipment than do LANs. • The world's most popular WAN is the Internet. It is the biggest WAN we have!
Network Designs • Peer to Peer Networks • All computers tend to support the same function. One computer is no different then another in terms of what it does. • An approach to computer networking where all computers share equivalent responsibility for processing data and storing data. • Peer to peer networking is common on small local area networks (LANs), particularly home networks. Both wired and wireless home networks can be configured as peer to peer environments. • Fairly easy to setup and configure.
Network Designs • Client/Server Networks • Utilizes client and server devices or computers each designed for specific purposes. • Client-server networks feature centralized server computers that store email, Web pages, files and or applications. • Client-server networks are much more common in business, government, and educational institutions. • More difficult to setup and configure.
Network Hardware –What do we use to connect network devices together ? • NIC – Network Interface Controller • A network adapter or controller provides the interface between a computer and a network connection, usually to a switch or hub port. • Many different types of network adapters exist today, typically depending on the type of connection used (copper, fiber, wireless).
Network Hardware –What do we use to connect network devices together ? • A Transfer Medium • Copper Cabling - Usually Category 5 or 6 -Very common in LANs. • Fiber Optic Cable - Carries information using pulses of light. These cables are designed for long distance network communications, although fiber to the home installations are becoming more common. • Radio Waves – Wireless networks use the radio spectrum to send and receive data.
Network Hardware –What do we use to connect network devices together ? • Network Hub • A small, simple, inexpensive device that joins multiple computers together. It repeats data from one port to all the other ports simultaneously. • The maximum bandwidth is shared among all the ports used. • Typically, non-managed. They are “dumb devices” and are no longer widely used. • Network Switch • A small hardware device that joins multiple computers together. It sends data only to the device it is intended for by finding what port that device is connected to. • The maximum bandwidth is given for each device connected to the switch. It is not shared between all ports as with the hub. • Usually a managed device. They are “smart” and know what other devices are attached to them. Widely used in today’s networks.
Network Hardware –What do we use to connect network devices together ? • Network Router • A router is a device in computer networking that forwards data packets to their destinations, based on their network addresses. • They are used to connect multiple LANs and WANs together. • Routers are intelligent devices. Most routers can actually determine the best and fastest route to another device or network. • They are the “central nervous system” of the Internet. Without routers, the Internet would not exist.
Network Topologies • A network topology refers to the layout of connected devices. • Think of a topology as a network's virtual shape or structure. • It’s shape does not necessarily correspond to the actual physical layout of the devices on the network but rather to it’s “electrical” characteristic.
Network Topologies • Bus Topology • Use a common backbone to connect all devices on the network • The backbone functions as a shared communication medium that devices attach or tap into with an interface connector. • A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message. • If the backbone cable fails, the entire network effectively becomes unusable.
Network Topologies • Ring Topology • Every device has exactly two neighbors for communication purposes. • All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). • A failure in any cable or device breaks the loop and can take down the entire network.
Network Topologies • Star Topology • Features a central connection point called a "hub" that may be a hub, switch or router. • Generally requires more cable because every device has it’s own connection to the central point, but a failure in any star network cable will only take down one computer's network access and not the entire LAN. • Typically used in most LAN networks.
Network Topologies • Tree Topology • Integrate multiple star topologies together onto a bus. • In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the "root" of a star of devices. • Supports future expandability of the network much better than a bus or star network. • The QSD WAN is a tree topology.
Network Topologies • Mesh Topology • Involve the concept of routes. • Unlike each of the previous topologies, messages sent on a mesh network can take any of several possible paths from source to destination. • A mesh network in which every device connects to every other is called a full mesh. • Maximizes redundancy. • Some WANs, most notably the Internet, employ mesh routing.
Network Technologies • Ethernet • Is a physical and data link layer technology for local area networks (LANs). Ethernet was invented by engineer Robert Metcalfe and others from Xerox PARC in 1975. • Most widely used network technology. • Supports speeds from 10Mbps to 10Gbps over copper, fiber, or wireless (speed is much slower over wireless). • Distance limitations depend on medium used. • Uses a set of rules to communicate with other devices and sends data using “best effort” attempts. This procedure is called CSMA/CD or Carrier Sense Multiple Access with Collision Detection and is used by governing the way computers share the medium.
Network Technologies • Token Ring • Uses a ring topology whereby the data is sent from one machine to the next and so on around the ring until it ends up back where it started. • It also uses a token passing procedure which means that a machine can only use the network when it has control of the Token, this ensures that there are no collisions because only one machine can use the network at any given time. • Obsolete technology. Presently, very few networks use token ring.
Network Protocols • A network protocol defines how devices on the network communicate with each other using a number of different rules and conventions. • Network protocols include mechanisms for devices to identify and make connections with each other, as well as formatting rules that specify how data is packaged into messages that are sent and received. • Some protocols also support message acknowledgement and data compression designed for reliable and/or high-performance network communication. • Hundreds of different computer network protocols have been developed each designed for specific purposes and environments.
Network Protocols – TCP/IP • The most common protocol is TCP/IP and is used to govern how computers across the Internet communicate. • TCP/IP is actually a set of protocols, not just one. It contains many different protocols: • HTTP – The World Wide Web • HTTPS – Secure World Wide Web • SMTP – E-mail • FTP – File transfer • DNS – Domain Name Resolution • SSH – Secure Shell • A multitude of different routing protocols (RIP, OSPF, BGP, EIGRP) • IP – Handles addressing between computer devices on a TCP/IP network. Every computer must have a different address.
Internet Protocol Address • An IP address is a logical address for a network adapter. The IP address uniquely identifies computers on a TCP/IP network. • An IP address can be private - for use on a local area network (LAN) - or public - for use on the Internet or other wide area network (WAN). • IP addresses can be determined statically (assigned to a computer by a system administrator) or dynamically (assigned by another device on the network on demand). • Two IP addressing standards are in use today. The IPv4 standard is most familiar to people and supported everywhere on the Internet, but the newer IPv6 standard is planned to replace it and starting to be deployed. • IPv4 addresses consist of four bytes (32 bits). Each byte of an IP address is known as an octet. Octets can take any value between 0 and 255. Various conventions exist for the numbering and use of IP addresses.
Network Firewall • Protects a computer network from unauthorized access. • May be hardware devices, software programs, or a combination of the two. • Guards an internal computer network (home, school, business) against malicious access from the outside. • May also be configured to limit access to the outside from internal users.
New Technological Buzzwords • Cloud Computing – Receiving services or applications from the “cloud”. • Virtualization – Both server and client based – Using a physical server or workstation to host multiple servers or workstations, some with different operating systems, through the use of virtualization software.
New Technological Buzzwords • Cloud controlling – used for controlling a wireless infrastructure, for example.
