CSC 2773 LAN Technologies PDF

CSC 2773 LAN TECHNOLOGIES 1. 0 L A N T ECHN OLOGIES 1. 0. 1 I E E E L A N STANDARDS 1. 0. 2 I E E E 8 0 2. 11 W I R E LESS STA NDAR DS Network Components Host Roles Every computer on a network is called a host or end device. Servers are computers that provide information...

CSC 2773 LAN TECHNOLOGIES 1. 0 L A N T ECHN OLOGIES 1. 0. 1 I E E E L A N STANDARDS 1. 0. 2 I E E E 8 0 2. 11 W I R E LESS STA NDAR DS Network Components Host Roles Every computer on a network is called a host or end device. Servers are computers that provide information to end devices: email servers web servers file server Clients are computers that send requests to the servers to retrieve information: web page from a web server ◦ email from an email server 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. Examples include switches, wireless access points, routers, and firewalls. Management of data as it flows through a network is also the role of an intermediary device, including: ◦ Regenerate and retransmit data signals. ◦ Maintain information about what pathways exist in the network. ◦ Notify other devices of errors and communication failures. Network Media Communication across a network is carried through a medium which allows a message to travel from source to destination. Media Types Description Metal wires within cables Uses electrical impulses Glass or plastic fibers within Uses pulses of light. cables (fiber-optic cable) Wireless transmission Uses modulation of specific frequencies of electromagnetic waves. LANs and WANS Network infrastructures vary greatly in terms of: Size of the area covered Number of users connected Number and types of services available Area of responsibility Two most common types of networks: Local Area Network (LAN) Wide Area Network (WAN). LANs and WANS A LAN is a network infrastructure that A WAN is a network infrastructure that spans a spans a small geographical area. wide geographical area. LAN WAN Interconnect end devices in a limited area. Interconnect LANs over wide geographical areas. Administered by a single organization or individual. Typically administered by one or more service providers. Provide high-speed bandwidth to internal devices. Typically provide slower speed links between LANs.  The Internet The internet is a worldwide collection of interconnected LANs and WANs. LANs are connected to each other using WANs. WANs may use copper wires, fiber optic cables, and wireless transmissions. The internet is not owned by any individual or group. The following groups were developed to help maintain structure on the internet: ◦ IETF ◦ ICANN ◦ IAB LAN Topologies End devices on LANs are typically interconnected using a star or extended star topology. Star and extended star topologies are easy to install, very scalable and easy to troubleshoot. Early Ethernet and Legacy Token Ring technologies provide two additional topologies: Bus – All end systems chained together and terminated on each end. Ring – Each end system is connected to its respective neighbors to form a ring. Data Link Frame  The Frame Data is encapsulated by the data link layer with a header and a trailer to form a frame. A data link frame has three parts: Header Data Trailer The fields of the header and trailer vary according to data link layer protocol. The amount of control information carried with in the frame varies according to access control information and logical topology. Frame Fields Field Description Frame Start and Stop Identifies beginning and end of frame Addressing Indicates source and destination nodes Type Identifies encapsulated Layer 3 protocol Control Identifies flow control services Data Contains the frame payload Error Detection Used for determine transmission errors  Layer 2 Addresses Also referred to as a physical address. Contained in the frame header. Used only for local delivery of a frame on the link. Updated by each device that forwards the frame. LAN and WAN Frames The logical topology and physical media determine the data link protocol used: Ethernet 802.11 Wireless Point-to-Point (PPP) High-Level Data Link Control (HDLC) Frame-Relay Each protocol performs media access control for specified logical topologies. Standards IEEE IEEE, or Institute of Electrical and Electronics Engineers, is an organization that develops standards for the electronics industry and computers. IEEE is composed of numerous scientists, engineers, and students from all over the globe. The main AIM of IEEE is to ensure foster technological innovation and excellence for the benefit of humanity. IEEE Standards The IEEE standards in computer networks ensure communication between various devices; it also helps to make sure that the network service, i.e., the Internet and its related technologies, must follow a set of guidelines and practices so that all the networking devices can communicate and work smoothly. Since there are various types of computer system manufacturers, the IEEE's computer society started a project in 1985 called Project 802 to enable standard communication between various devices. IEEE Standards Under this project, the IEEE divided the data link layer into two sub-parts, namely: LLC or Logical Link Control and MAC or Media Access Control. The standards that deal with computer networking (networking in general) are called the IEEE 802 standards. The IEEE 802 is a collection of networking standards that deals with the data link layer and physical layer technologies like Ethernet and wireless communications. The IEEE standards for computer networks developed IEEE 802 standards which ensure that various devices having different network hardware can easily connect over the network and exchange data. The IEEE 802 standards also make sure that the network connectivity and management are easier. Example of IEEE Standards – 802.11 The IEEE 802.11 standard in computer networks is used in various homely devices like laptops, printers, smartphones, and various other devices that allow them to communicate with each other using wireless communications. List of IEEE Standards List of IEEE Standards List of IEEE Standards List of IEEE Standards Wired LAN FOCUSING ON 802.3 STANDARDS 802.3 Standards 802.3, or IEEE 802.3, is a working group of standard specifications for Ethernet, a method of packet-based physical communication in a local area network. It defines a physical layer and a data link layer for media access control, or MAC address, for a wired, fast Ethernet network connection. These physical connections are made between nodes or devices such as routers, switches and hubs via copper or fiber cables. In general, IEEE 802.3 standards specify the physical media and the working characteristics of Ethernet. However, there are many variations of this standard used today. 802.3 Standards (evolution) Wireless LAN FOCUSING ON 802.11 STANDARDS Benefits of Wireless A Wireless LAN (WLAN) is a type of wireless network that is commonly used in homes, offices, and campus environments. WLANs make mobility possible within the home and business environments. Wireless infrastructures adapt to rapidly changing needs and technologies. Types of Wireless Networks Wireless Personal-Area Network (WPAN) – Low power and short-range (20-30ft or 6-9 meters). Based on IEEE 802.15 standard and 2.4 GHz frequency. Bluetooth and Zigbee are WPAN examples. Wireless LAN (WLAN) – Medium sized networks up to about 300 feet. Based on IEEE 802.11 standard and 2.4 or 5.0 GHz frequency. Wireless MAN (WMAN) – Large geographic area such as city or district. Uses specific licensed frequencies. Wireless WAN (WWAN) – Extensive geographic area for national or global communication. Uses specific licensed frequencies. Wireless Technologies Bluetooth – IEEE WPAN standard used for device pairing at up to 300ft (100m) distance. Bluetooth Low Energy (BLE) – Supports mesh topology to large scale network devices. Bluetooth Basic Rate/Enhanced Rate (BR/EDR) – Supports point-to-point topologies and is optimized for audio streaming. WiMAX (Worldwide Interoperability for Microwave Access) Alternative broadband wired internet connections. IEEE 802.16 WLAN standard for up 30 miles (50 km). Wireless Technologies Cellular Broadband – Carry both voice and data. Used by phones, automobiles, tablets, and laptops. Global System of Mobile (GSM) – Internationally recognized Code Division Multiple Access (CDMA) – Primarily used on the US. Satellite Broadband Uses directional satellite dish aligned with satellite in geostationary orbit. Needs clear line of site. Typically used in rural locations where cable and DSL are unavailable. 802.11 WLAN Standards 802.11 WLAN standards define how radio frequencies are used for wireless links. IEEE Standard Radio Frequency Description 802.11 2.4 GHz Data rates up to 2 Mb/s 802.11a 5 GHz Data rates up to 54 Mb/s Not interoperable with 802.11b or 802.11g 802.11b 2.4 GHz Data rates up to 11 Mb/s Longer range than 802.11a and better able to penetrate building structures 802.11g 2.4 GHz Data rates up to 54 Mb/s Backward compatible with 802.11b 802.11n 2.4 and 5 GHz Data rates 150 – 600 Mb/s Require multiple antennas with MIMO technology 802.11ac 5 GHz Data rates 450 Mb/s – 1.3 Gb/s Supports up to eight antennas 802.11ax 2.4 and 5 GHz High-Efficiency Wireless (HEW) Capable of using 1 GHz and 7 GHz frequencies Radio Frequencies All wireless devices operate in the range of the electromagnetic spectrum. WLAN networks operate in the 2.4 and 5 GHz frequency bands. ◦ 2.4 GHz (UHF) – 802.11b/g/n/ax ◦ 5 GHz (SHF) – 802.11a/n/ac/ax