Network Administration_notes.pdf

Network Administration What is a Network? According to the Florida Center for Instructional Technology (1997-2013), a network consists of two or more computers that are linked in order to share resources. The computers on a network may be linked through cables....

Network Administration What is a Network? According to the Florida Center for Instructional Technology (1997-2013), a network consists of two or more computers that are linked in order to share resources. The computers on a network may be linked through cables. The nodes of a computer network may include personal computers, servers, networking hardware, or other specialized or general-purpose hosts. Hostnames serve as memorable labels for the nodes. Computer networks may be classified by many criteria, including the transmission medium used to carry signals, bandwidth, and communications protocols Dimitrios Serpanos and Tilman Wolf (2011), virtualization in networks requires that multiple networks with different protocol stacks can coexist on the same physical infrastructure. Virtualization software ensures that resources are shared among the virtual operating systems. Three types of resources 1. Link bandwidth a. physical links may carry traffic from multiple virtual network slices. A time division multiplexing approach may be used. Virtual LANs are one possible way to separate physical link resources into multiple virtual topologies. 2. Processing resources a. The processing resources of these systems need to be shared among all slices and thus require isolation. b. On multicore processing systems, individual processors can be dedicated to different slices. c. On single-core systems, operating system techniques can be employed to implement processor sharing. 3. Memory resources a. Memory is necessary to store packets b. Memory virtualization techniques can be used to provide a layer of indirection between packet processing functions and physical memories, where isolation can implemented. Different forms Globalization Texting Social Media Collaboration Tools Blogs Wikis Podcasting Effects of Computer Networks Computer network gradually change the way we do transactions, analyzing data, data mining, searching the net and more. Common feat of network that affects the way we work Data networks have evolved into helping support the way we work. Online learning opportunities decrease costly and time consuming travel. Employee training is becoming more cost effective. We listen to music, watch movies, read books, and download material for future offline access. Networks allow online gaming in ways that were not possible 20 years ago. Offline activities have also been enhanced by networks including global communities for a wide range of hobbies and interests. Networks of Many Sizes designing a topology of network the network designer should consider the environment, the geographical layout, and the structure of a place. Examples of Network size: Small Home Networks – connect a few computers to each other and the Internet. Small Office/Home Office – enables computer within a home or remote office to connect to a corporate network. Medium to Large Networks – many locations with hundreds or thousands of interconnected computers. World Wide Networks – connects hundreds of millions of computers worldwide such as the Internet. Host and Devices Two Kinds of Host o Servers – this computers that provide information to end devices on the network. For example, email servers, web servers, or file server. o Clients - computers that send requests to the servers to retrieve information such as a web page from a web server or email from an email server. It is typical for a client to also function as the server. These networks are called peer-to- peer networks. Peer-to-peer networking advantages: easy to set up, less complex, and lower cost. Disadvantages: no centralized administration, not as secure, not scalable, and slower performance. A network can be as simple as a single cable connecting two computers or as complex as a collection of networks that span the globe Network infrastructure contains three broad categories of network components: Devices Media Services Network Components End devices An end device is where a message originates from or where it is received. Data originates with an end device, flows through the network, and arrives at an end device. Intermediary Network Devices An intermediary device interconnects end devices in a network. The management of data as it flow through a network is also the role of an intermediary device including: Regenerate and retransmit data signals. Maintain information about what pathways exist through the network and internetwork. Notify other devices of errors and communication failures. Networks typically use three types of media: Metallic wires within cables, such as copper Glass, such as fiber optic cables  Wireless transmission Network diagrams, often called topology diagrams, use symbols to represent devices within the network. Understand the following terms: Network Interface Card (NIC) Physical Port Interface Network Topology network topology refers to how various nodes, devices, and connections on your network are physically or logically arranged. There are two approaches to network topology: Physical and Logical Physical network topology, as the name suggests, refers to the physical connections and interconnections between nodes and the network Logical network topology is a little more abstract and strategic, referring to the conceptual understanding of how and why the network is arranged the way it is, and how data moves through it. A higher-level idea of how the network is set up, including which nodes connect to each other. Logical network topology includes any virtual and cloud resources. Types of Networks Two most common types of networks: Local Area Network (LAN) – spans a small geographic area owned or operated by an individual or IT department. Wide Area Network (WAN) – spans a large geographic area typically involving a telecommunications service provider. Other types of networks: Metropolitan Area Network (MAN) Wireless LAN (WLAN) Storage Area Network (SAN) The Internet The Internet is a worldwide collection of interconnected LANs and WANs. IETF (Internet Engineering Task Force) - It develops open standards through open processes with one goal in mind: to make the Internet work better. They the one who standardized the TCP/IP a non-profit organization ICANN (Internet Corporation for Assigned Names) - an American multi-stakeholder group and nonprofit organization responsible for coordinating the maintenance and procedures of several databases. IAB (Internet Architecture Board) - provides long-range technical direction for Internet development, ensuring the Internet continues to grow and evolve as a platform for global communication and innovation. Ensure that the Internet is a trusted medium of communication that provides a solid technical foundation for privacy and security. An intranet is a private collection of LANs and WANs internal to an organization that is meant to be accessible only to the organizations members. An organization might use an extranet to provide secure access to their network for individuals who work for a different organization that need access to their data on their network.