5.0 Comparing Local Networking Hardware ____________________________________________________________________ ____________________________________________________________________ 5.1 Network Types ____________________________________________________________________ 5.1.1 LANs and WANs Local Area Network (LAN) A local area network is a group of computers connected by cabling and one or more network switches that are all installed at a single geographical location. A LAN might span a single floor in a building, a whole building, or multiple nearby buildings (a campus). Any network where the nodes are within about 1 or 2 km (or about 1 mile) of one another can be thought of as "local." LAN cabling and devices are typically owned and managed by the organization that uses the network. Most cabled LANs are based on the Ethernet standards maintained by the Institute of Electrical and Electronics Engineers (IEEE). The IEEE 802.3 standards are designated xBASE-Y, where x is the nominal data rate, and Y is the cable type. For example: 100BASE-T refers to Fast Ethernet over copper twisted pair cabling. Fast Ethernet works at 100 Mbps. 1000BASE-T refers to Gigabit Ethernet over copper twisted pair cabling. Gigabit Ethernet works at 1000 Mbps (or 1 Gbps). 1000BASE-T is the mainstream choice of standard for most LANs. 10GBASE-T refers to a copper cabling standard working at 10 Gbps. The majority of LANs will use copper cabling, which uses electrical signaling to communicate data. Oftentimes, the backbone of the LAN or some special Ethernet networks will transmit data over fiber optic cabling, which uses pulses of light to communicate data. Wide Area Network (WAN) Where a LAN operates at a single site, a wide area network spans multiple geographic locations. One example of a WAN is the Internet, a global network of networks. A company dedicated to facilitating access to the Internet from local networks is called an Internet Service Provider (ISP). Most private or enterprise WANs use cabling and equipment leased from an ISP to interconnect two or more LAN sites. For example, a company might use a WAN to connect branch office sites to the LAN at its head office. Wireless LANs A wireless local area network (WLAN) uses radios and antennas for data transmission and reception. Most WLANs are based on the IEEE 802.11 series of standards. IEEE 802.11 is better known by its brand name, WiFi. Wi-Fi and Ethernet technologies complement one another and are often used together as segments within the same local network. This allows computers with wired and wireless networking adapters on the same LAN to communicate with one another. Metropolitan Area Networks The term metropolitan area network (MAN) can be used to mean a specific network type covering an area equivalent to a city or other municipality. It could mean a company with multiple connected networks within the same metropolitan area - basically, a MAN will be larger than a LAN but smaller than a WAN. Personal Area Networks A personal area network (PAN) refers to using wireless connectivity to connect to devices at a range of a few meters. A PAN can be used to share data between a PC and mobile devices and wearable technology devices, such as smartwatches. It can also connect PCs and mobile devices to peripheral devices, such as printers, headsets, speakers, and video displays. The most common example of a PAN is wearable Bluetooth devices such as earbuds and smartwatches connected to the cellphone on a person. As digital and network functionality continues to be embedded in more and more everyday objects (typically referred to as the Internet of Things or "IoT"), appliances, and clothing, the use of PANs will only grow. Storage Area Network A Storage Area Network (SAN) refers to a specialized network that is dedicated to storage devices. Servers can connect to the storage devices as if they are directly attached. The key characteristics of a SAN include: Dedicated Network - The SAN must be attached to a dedicated network that is independent of the LAN. This ensures that the SAN traffic does not interfere with other network operations. Block-Level Access - Data sent across the SAN is transferred in raw chunks of data with no file system structure called blocks. This allows for efficient data transfers and flexible storage management options. Consolidated Storage - Multiple types of storage, such as RAID arrays and tape drives, are joined together in the SAN, which sets up centralized storage resources for servers. High Speed - SANs will typically utilize high-speed connections such as Fibre Channel or Internet Small Computer System Interface (iSCSI) for data transfer. ____________________________________________________________________ 5.1.2 SOHO and Enterprise Networks A small office/home office (SOHO) LAN is a small network possibly using a centralized server, in addition to client devices and printers, but often using a single networking appliance to provide LAN and Internet connectivity. This is often referred to as a "SOHO router," "Internet router," or "broadband router." SOHO networks are typically designed to support a small number of users. A typical SOHO network layout A network layout for SOHO. Image © 123RF.com. Description Networks supporting larger businesses or academic institutions have networking appliances with the same basic functions as a SOHO router, but because they must support more clients with a greater degree of reliability, each function is performed by a separate network device. The following graphic illustrates how an enterprise LAN might be implemented. Each segment of the network is designed as a modular function. Client computers and printers are located in work areas and connected to the network by cabling running through wall conduit. Laptops and mobile devices connect to the network via wireless access points (APs). Network servers are separated from client computers in a server room. Workgroup switches connect each of these blocks to core/distribution switches, routers, and firewalls. These network appliances allow authorized connections between the clients and servers. Positioning network components A network infrastructure diagram showcases the flow of data and positioning of various components. Image © 123RF.com. Description Internet services are placed in protected screened subnets, which represent a border between the private LAN and the public Internet. Traffic to and from this zone is strictly filtered and monitored. Network border services provide Internet access for employees, email and communications, remote access and WAN branch office links via virtual private networks (VPNs), and web services for external clients and customers. ____________________________________________________________________ 5.1.3 Datacenters A small office/home office (SOHO) LAN is a small network possibly using a centralized server, in addition to client devices and printers, but often using a single networking appliance to provide LAN and Internet connectivity. This is often referred to as a "SOHO router," "Internet router," or "broadband router." SOHO networks are typically designed to support a small number of users. A typical SOHO network layout A network layout for SOHO. Image © 123RF.com. Description Networks supporting larger businesses or academic institutions have networking appliances with the same basic functions as a SOHO router, but because they must support more clients with a greater degree of reliability, each function is performed by a separate network device. The following graphic illustrates how an enterprise LAN might be implemented. Each segment of the network is designed as a modular function. Client computers and printers are located in work areas and connected to the network by cabling running through wall conduit. Laptops and mobile devices connect to the network via wireless access points (APs). Network servers are separated from client computers in a server room. Workgroup switches connect each of these blocks to core/distribution switches, routers, and firewalls. These network appliances allow authorized connections between the clients and servers. Positioning network components A network infrastructure diagram showcases the flow of data and positioning of various components. Image © 123RF.com. Description Internet services are placed in protected screened subnets, which represent a border between the private LAN and the public Internet. Traffic to and from this zone is strictly filtered and monitored. Network border services provide Internet access for employees, email and communications, remote access and WAN branch office links via virtual private networks (VPNs), and web services for external clients and customers. ____________________________________________________________________ ____________________________________________________________________ 5.2 Networking Hardware ____________________________________________________________________ 5.2.1 Network Interface Cards Ethernet communications are established by either electrical signaling over copper twisted pair cable or pulses of light transmitted over fiber optic cable. The physical connection to the cable is made using a transceiver port in the computer's network interface card (NIC). The majority of PC motherboards today have a built-in 1000BASE-T compatible adapter. You might use a NIC adapter card to support other types of Ethernet, such as fiber optic. You can also purchase cards with multiple ports of the same type - two or four 1000BASE-T ports, for instance. The multiple ports can be bonded to create a higher-speed link. Four Gigabit Ethernet ports could be bonded to give a nominal link speed of 4 Gbps. For the NIC to be able to process the electrical or light signals as digital data, the signals must be divided into regular units with a consistent format. There must also be a means for each node on the local network to address communications to other nodes. Ethernet provides a data link protocol to perform these framing and addressing functions. Each Ethernet NIC port has a unique hardware/physical address, called the "media access control" (MAC) address. Each frame of Ethernet data identifies the source MAC address and destination MAC address in fields in a header. Captured Ethernet frame showing the destination and source MAC addresses. The destination address is a broadcast address A screenshot of the Wireshark network protocol analyzer capturing packets from a network interface. Screenshot courtesy of Wireshark. Description A MAC address consists of 48 binary digits, making it six bytes in size. A MAC address is typically represented as 12 digits of hexadecimal. Hexadecimal is a numbering system often used to represent network addresses of different types. A hexadecimal digit can be one of sixteen values: 0–9 and then A, B, C, D, E, F. Each hexadecimal digit represents half a byte (or four bits aka a nibble). A MAC address is typically written out with a colon separating every two digits. They may occasionally use a hyphen or no separator - for example, 00:60:8C:12:3A:BC or 00608C123ABC. A MAC address is broken into two distinct parts: The first 24 bits are known as the Organizationally Unique Identifier (OUI). This identifies the manufacturer of the NIC. The last 24 bits are known as the Network Interface Controller (NIC) Specific. This is a unique identifier for each NIC. When you convert the first two hex digits of a MAC address to binary, the two right-most bits act as flags. The very last bit shows individual (0) versus group / multicast (1). The bit just to its left shows universally administered (0, factory) versus locally administered (1, set by software). Example: the address 01:13:10:6B:17:A8 starts with 01, which is 00000001 in binary. The last bit is 1, so it is multicast, and the next bit is 0, so it is globally unique. Interactive Mobile Placeholder This content is only available on larger screen sizes. Please revisit this page on a larger device. ____________________________________________________________________ 5.2.2 Patch Panels In most types of office cabling, the computer is connected to a wall port and via cabling running through the walls to a patch panel. The cables running through the walls are terminated to insulation displacement connector (IDC) punchdown blocks at the back of the panel. IDCs at the rear of a patch panel A patch panel with the insulation displacement connector at the back. Image by plus69 © 123RF.com. The other side of the patch panel has pre-wired RJ45 ports. A patch cord is used to connect a port on the patch panel to a port on an Ethernet switch. This cabling design makes it easier to change how any given wall port location is connected to the network via switch ports. Patch panel with prewired RJ45 ports A neatly organized network rack with multiple patch panels, orange Ethernet cables, and white cable loops for structured cable management. Image by Svetlana Kurochkina © 123RF.com. Note: It is vital to use an effective labeling system when installing structured cabling so that you know which patch panel port is connected to which wall port. ____________________________________________________________________ 5.2.3 Switches Ethernet switches are used to connect multiple devices inside of a network together. The switch provisions one port for each device that needs to connect to the network. When a device is connected to the switch, it adds the device's MAC address to a table and keeps track of which port it connects to. When a frame comes in, the switch is able to decode each frame and identify the source and destination MAC addresses. The switch is able to intelligently forward it to the port that is a match for the destination MAC address. Switch operation A switch operation process. Image © 123RF.com. Description This means that each switch port is considered a separate collision domain, and the negative effects of collisions are eliminated. Each computer has a full duplex connection to the network and can send and receive simultaneously at the full speed supported by the network cabling and NIC. Note: When a computer sends a frame, the switch reads the source address and adds it to its MAC address table. If a destination MAC address is not yet known, the switch floods the frame out of all ports. ____________________________________________________________________ 5.2.4 Unmanaged and Managed Switches An unmanaged switch performs its function without requiring any sort of configuration. You just power it on and connect some hosts to it, and it establishes Ethernet connectivity between the network interfaces without any more intervention. Common unmanaged switches will have four or eight ports, as they are typically used in small networks. There is an unmanaged four-port switch embedded in most of the SOHO router/modems supplied by Internet Service Providers (ISPs) to connect to their networks. Larger workgroups and corporate networks require additional functionality in their switches. Switches designed for larger LANs are called a managed switch. A managed switch will work as an unmanaged switch out-of-the-box, but an administrator can connect to it over a management port to configure security settings and then choose options for the switch's more advanced functionality. Most managed switches are designed to be bolted into standard network racks. A typical workgroup switch will come with 24 or 48 access ports for client PCs, servers, and printers. These switches have uplink ports allowing them to be connected to other switches. A workgroup switch A workgroup switch with multiple ports on the front panel. Image © 123RF.com. An enterprise might also use modular switches. These provide a power supply and fast communications backplane to interconnect multiple switch units. This enables the provisioning of hundreds of access ports via a single compact appliance. Modular chassis allows provisioning multiple access switches Two modular chassis with multiple access switches. Image © 123RF.com. Configuring a managed switch can be performed over either a web or command line interface. Viewing interface configuration on a Cisco switch The interface configuration on a Cisco switch. ____________________________________________________________________ 5.2.5 Power over Ethernet Power over Ethernet is a means of supplying electrical power from a switch port over ordinary data cabling to a powered device (PD), such as a voice over IP (VoIP) handset, camera, or wireless access point. PoE is defined in several IEEE standards: 802.3af (Type 1 PoE or 2-pair PoE) allows powered devices to draw up to about 13 W. Power is supplied as 350mA@48V and limited to 15.4 W, but the voltage drop over the maximum 100m (328 feet) of cable results in usable power of around 13 W. Basic devices such as a VoIP handset, basic wireless access points, and basic security cameras will use this standard. 802.3at (PoE+ or Type 2 PoE) allows powered devices to draw up to about 25 W, with a maximum current of 600 mA. Devices that require more power, such as advanced wireless access points, pan-tilt-zoom security cameras, and video IP phones, will use this standard. 802.3bt (PoE++, Type 3 and Type 4 PoE, 4PPoE) supplies up to about 51 W (Type 3) or 73 W (Type 4) usable power. Devices such as LED lighting, digital signage, point-of-sale systems, and other high-power devices will use this standard. PoE Switch A PoE-enabled switch is referred to as endspan power sourcing equipment (PSE). When a device is connected to a port on a PoE switch, the switch goes through a detection phase to determine whether the device is PoE enabled. If so, it determines the device's power consumption and sets an appropriate supply voltage level. If not, it does not supply power over the port and, therefore, does not damage non-PoE devices. Powering these devices through a switch is more efficient than using a wall-socket AC adapter for each appliance. It also allows network management software to control the devices and apply energy-saving schemes, such as making unused devices go into sleep states and power capping. PoE Injector If the switch does not support PoE, a device called a "power injector" (or "midspan") can be used. One port on the injector is connected to the switch port. The other port is connected to the device. The overall cable length cannot exceed 100m. ____________________________________________________________________ ____________________________________________________________________ 5.3 Network Cable Types ____________________________________________________________________ 5.3.1 Unshielded Twisted Pair Power over Ethernet is a means of supplying electrical power from a switch port over ordinary data cabling to a powered device (PD), such as a voice over IP (VoIP) handset, camera, or wireless access point. PoE is defined in several IEEE standards: 802.3af (Type 1 PoE or 2-pair PoE) allows powered devices to draw up to about 13 W. Power is supplied as 350mA@48V and limited to 15.4 W, but the voltage drop over the maximum 100m (328 feet) of cable results in usable power of around 13 W. Basic devices such as a VoIP handset, basic wireless access points, and basic security cameras will use this standard. 802.3at (PoE+ or Type 2 PoE) allows powered devices to draw up to about 25 W, with a maximum current of 600 mA. Devices that require more power, such as advanced wireless access points, pan-tilt-zoom security cameras, and video IP phones, will use this standard. 802.3bt (PoE++, Type 3 and Type 4 PoE, 4PPoE) supplies up to about 51 W (Type 3) or 73 W (Type 4) usable power. Devices such as LED lighting, digital signage, point-of-sale systems, and other high-power devices will use this standard. PoE Switch A PoE-enabled switch is referred to as endspan power sourcing equipment (PSE). When a device is connected to a port on a PoE switch, the switch goes through a detection phase to determine whether the device is PoE enabled. If so, it determines the device's power consumption and sets an appropriate supply voltage level. If not, it does not supply power over the port and, therefore, does not damage non-PoE devices. Powering these devices through a switch is more efficient than using a wall-socket AC adapter for each appliance. It also allows network management software to control the devices and apply energy-saving schemes, such as making unused devices go into sleep states and power capping. PoE Injector If the switch does not support PoE, a device called a "power injector" (or "midspan") can be used. One port on the injector is connected to the switch port. The other port is connected to the device. The overall cable length cannot exceed 100m. ____________________________________________________________________ 5.3.2 Shielded Twisted Pair Shielded Twisted Pair (STP) provides extra protection against interference. STP cables are typically a requirement in environments with high levels of external interference, such as cable that must be run in proximity to fluorescent lighting, power lines, motors, and generators. Shielded cable can be referred to generically as "STP," but several types of shielding and screening exist: Foiled Unshielded Twisted Pair (F/UTP) cable has a single foil shield that surrounds all wires in the cable. This type of cable may also be called screened twisted pair (ScTP) or sometimes just foiled twisted pair (FTP). This type of cable provides decent protection against electromagnetic interference (EMI) and crosstalk at a reasonable cost. Shielded Foiled Twisted Pair (S/FTP) cabling has a braided outer screen and foil-shielded pairs. This type of cable provides the best protection against EMI and crosstalk but is expensive and less flexible. There are also variants with a foil outer shield (F/FTP). Unshielded with Foiled Twisted Pair (U/FTP) cable has no outer shield, but each pair of wires has a foil shield around them. This provides good protection against EMI and crosstalk. F/UTP cable with a foil screen surrounding unshielded pairs A shielded twisted-pair cable with four color-coded wire pairs, a protective foil screen, and a surrounding insulated outer jacket. Image by Baran Ivo and released to public domain. The screening/shielding elements of shielded cable must be bonded to the connector to prevent the metal from acting as a large antenna and generating interference. Modern F/UTP and S/FTP solutions (using appropriate cable, connectors, and patch panels) facilitate this by incorporating bonding within the design of each element. ____________________________________________________________________ 5.3.4 Cat Standards A Category (Cat) standard defines the performance of twisted-pair cabling. Higher Cat specification cable is capable of higher data rates. Cat specifications are defined in the TIA/EIA-568-C Commercial Building Telecommunications Cabling Standards. Cat Max. Transfer Rate Max. Distance Ethernet Standard Support 5 100 Mbps 100 m (328 ft) 100BASE-TX (Fast Ethernet) 5e 1 Gbps 100 m (328 ft) 1000BASE-T (Gigabit Ethernet) 6 1 Gbps 100 m (328 ft) 1000BASE-T (Gigabit Ethernet) 10 Gbps 55 m (180 ft) 10GBASE-T (10G Ethernet) 6A 10 Gbps 100 m (328 ft) 10GBASE-T (10G Ethernet) 7 10 Gbps 100 m (328 ft) 10GBASE-T (10G Ethernet) 100 Gbps 15 m (50 ft) 100GBASE-T (100G Ethernet) 8 25 Gbps 30 m (100 ft) 25GBASE-T (25G Ethernet) 40 Gbps 30 m (100 ft) 40GBASE-T (40G Ethernet) The Cat specification is printed on the cable jacket along with the cable type (UTP or F/UTP, for instance). Cat 5 cable supports the older 100 Mbps Fast Ethernet standard. It is no longer commercially available. A network cabled with Cat 5 will probably need to be rewired to support Gigabit Ethernet. Cat 5e would still be an acceptable choice for providing Gigabit Ethernet links for client computers, but most sites would now opt to install Cat 6 cable. The improved construction standards for Cat 6 mean that it is more reliable than Cat 5e for Gigabit Ethernet, and it can also support 10 Gbps, though over reduced range. Cat 6A supports 10 Gbps over 100 m, but the cable is bulkier and heavier than Cat 5e and Cat 6, and the installation requirements are more stringent, so fitting it within pathways designed for older cable can be problematic. TIA/EIA standards recommend Cat 6A for healthcare facilities, with Power over Ethernet (PoE) 802.3bt installations, and for running distribution system cable to wireless access points. Cat 7 and Cat 8 cables are not widely in use yet. These cables are mostly used in datacenters where shorter runs that require high bandwidth are needed. Cat 7 uses a special type of connector called a GG45, which is not compatible with an RJ45 port. Cat 8 cable can use either the GG45 or RJ45 connector. ____________________________________________________________________ 5.3.5 Copper Cabling Connectors Twisted pair cabling for Ethernet can be terminated using modular RJ45 connectors. RJ45 connectors are also referred to as "8P8C," standing for eight-position/eight-contact. Each conductor in four-pair Ethernet cable is color-coded. Each pair is assigned a color (orange, green, blue, and brown). The first conductor in each pair has a predominantly white insulator with stripes of the color; the second conductor has an insulator with a solid color. Twisted pair RJ45 connectors An R J-45 connector and port used for Ethernet connections. Image © 123RF.com. Description The EIA/TIA-568 standard defines two methods for terminating twisted pair: T568A/T568B. In T568A, pin 1 is wired to green/white, pin 2 is wired to green, pin 3 is wired to orange/white, and pin 6 is wired to orange. In T568B, the position of the green and orange pairs is swapped over, so that orange terminates to 1 and 2 and green to 3 and 6. When cabling a network, it is best to use the same termination method consistently. A straight-through Ethernet cable is wired with the same type of termination at both ends. Twisted-pair can also be used with RJ11 connectors. Unlike the four-pair cable used with Ethernet, RJ11 is typically used to terminate two-pair cable, which is widely used in telephone systems and with broadband digital subscriber line (DSL) modems. ____________________________________________________________________ 5.3.6 Copper Cabling Installation Tools Data cable for a typical office is installed as a structured cabling system. With structured cabling, the network adapter port in each computer is connected to a wall port using a flexible patch cord. Behind the wall port, permanent cable is run through the wall and ceiling to an equipment room and connected to a patch panel. The port on the patch panel is then connected to a port on an Ethernet switch. A structured cabling system uses two types of cable termination: Patch cords are terminated using RJ45 plugs crimped to the end of the cable. Permanent cable is terminated to wall ports and patch panels using insulation displacement connectors (IDC), also referred to as "punchdown blocks." Note: The 100 m distance limitation is for the whole link, referred to as "channel link." Each patch cord can only be up to 5 m long. Permanent link uses solid cable with thicker wires. Patch cords use stranded cable with thinner wires that are more flexible but also suffer more from attenuation. Installing cable in this type of system involves the use of cable strippers, punchdown tools, and crimpers. Cable Stripper and Snips To terminate cable, a small section of outer jacket must be removed to expose the wire pairs. This must be done without damaging the insulation on the inner wire pairs. A cable stripper is designed to score the outer jacket just enough to allow it to be removed. Set the stripper to the correct diameter, and then place the cable in the stripper and rotate the tool once or twice. The score cut in the insulation should now allow you to remove the section of jacket. A cable stripper A cable stripper with red handles. Image by gasparij © 123RF.com Most Cat 6 and all Cat 6A cable has a plastic star filler running through it that keeps the pairs separated. You need to use electrician's scissors (snips) to cut off the end of this before terminating the cable. There will also be a nylon thread called a "ripcord." This can be pulled down the jacket to open it up more if you damaged any of the wire pairs initially. Snip any excess ripcord before terminating the cable. Punchdown Tool A punchdown tool is used to fix each conductor into an IDC. First, untwist the wire pairs and lay them in the color-coded terminals in the IDC in the appropriate termination order (T568A or T568B). To reduce the risk of interference, no more than ½" (13 mm) should be untwisted. Use the punchdown tool to press each wire into the terminal. Blades in the terminal cut through the insulation to make electrical contact with the wire. Connecting UTP cable to IDCs using a punchdown tool. A person using a punch down tool to connect a UTP cable to an IDC. Image by dero2084 © 123RF.com. Crimper A crimper is used to fix a jack to a patch cord. Orient the RJ45 plug so that the tab latch is underneath. Pin 1 is the first pin on the left. Arrange the wire pairs in the appropriate order (T568A or T568B), and then push them into the RJ45 plug. Place the plug in the crimper tool, close it tightly to pierce the wire insulation at the pins, and seal the jack to the outer cable jacket. A wire crimper. A crimping tool with blue handles. Image by gasparij © 123RF.com ____________________________________________________________________ 5.3.7 Copper Cabling Test Tools Once you have terminated cable, you must test it to ensure that each wire makes good electrical contact and is in the correct pin position. The best time to verify wiring installation and termination is just after you have made all the connections. This means you should still have access to the cable runs. Identifying and correcting errors at this point will be much simpler than when you are trying to set up enduser devices. You can use several cabling and infrastructure troubleshooting devices to assist with this process. Cable Tester A cable tester is a pair of devices designed to attach to each end of a cable. It can be used to test a patch cord or connected via patch cords to a wall port and patch panel port to test the permanent link. The tester energizes each wire in turn, with an LED indicating successful termination. If an LED does not activate, the wire is not conducting a signal, typically because the insulation is damaged or the wire isn't properly inserted into the plug or IDC. If the LEDs do not activate in the same sequence at each end, the wires have been terminated to different pins at each end. Use the same type of termination on both ends. Basic cable tester A network cable tester shows both ends of a cable connected to it. Image by samum © 123RF.com Toner Probe Many cable testers also incorporate the function of a toner probe, which is used to identify a cable from within a bundle. This may be necessary when the cables have not been labeled properly. The tone generator is connected to the cable using an RJ45 jack and applies a continuous audio signal on the cable. The probe is used to detect the signal and follow the cable over ceilings and through ducts or identify it from within the rest of the bundle. Note: Disconnect the other end of the cable from any network equipment before activating the tone generator. Loopback Plug A loopback adapter is used to test a NIC or switch port. You can make a basic loopback plug from a 6" cable stub where the wires connect pin 1 to pin 3 and pin 2 to pin 6. When you connect a loopback plug to a port, you should see a solid link LED showing that the port can send and receive. Note: A loopback plug made from a cable stub is unlikely to work with Gigabit Ethernet ports. You can obtain manufactured Gigabit port loopback testers. A loopback plug An R J-45 connector along with the transmit and receive lines that cross over. Image © 123RF.com ____________________________________________________________________ 5.3.8 Network Taps A network tap is used to intercept the signals passing over a cable and send them to a packet or protocol analyzer. Taps are either powered or unpowered: A passive test access point (TAP) is a box with ports for incoming and outgoing network cabling and an inductor or optical splitter that physically copies the signal from the cabling to a monitor port. No logic decisions are made, so the monitor port receives every frame regardless if it is corrupt or malformed or not and the copying is unaffected by load. An active TAP is a powered device that performs signal regeneration, which may be necessary in some circumstances. Gigabit signaling over copper wire is too complex for a passive tap to monitor, and some types of fiber links may be adversely affected by optical splitting. Because it performs an active function, the TAP becomes a point of failure for the links during power loss. Note: Network sniffing can also be facilitated using a switched port analysis/mirror port. This means that the sensor is attached to a specially configured port on a network switch. The mirror port receives copies of frames addressed to nominated access ports (or all the other ports). ____________________________________________________________________ 5.3.9 Copper Cabling Installation Considerations Installation of cable must be compliant with local building regulations and fire codes. This means that specific cable types must be used in some installation scenarios. Plenum Cable A plenum space is a void in a building designed to carry heating, ventilation, and air conditioning (HVAC) systems. Plenum space is typically a false ceiling, though it could also be constructed as a raised floor. As it makes installation simpler, this space has also been used for communications wiring in some building designs. Plenum space is an effective conduit for fire, as there is plenty of airflow and no fire breaks. If the plenum space is used for heating, there may also be higher temperatures. Therefore, building regulations require the use of fire-retardant plenum cable in such spaces. Plenum cable must not emit large amounts of smoke when burned, be self-extinguishing, and meet other strict fire safety standards. General purpose (non-plenum) cabling uses PVC jackets and insulation. Plenum-rated cable uses treated PVC or fluorinated ethylene polymer (FEP). This can make the cable less flexible, but the different materials used have no effect on bandwidth. Data cable rated for plenum use under the US National Electrical Code (NEC) is marked as CMP on the jacket. General-purpose cables are marked as CMG or CM. Direct Burial Outside plant (OSP) is cable run on the external walls of a building or between two buildings. This makes the cable vulnerable to different types of weathering: Aerial cable is typically strung between two poles or anchors. The ultraviolet (UV) rays in sunlight plus exposure to more extreme and changing temperatures and damp conditions will degrade regular PVC. Conduit can provide more protection for buried cable runs. Such cable can still be exposed to extreme temperatures and damp conditions, however, so regular PVC cable should not be used. Direct burial cable is laid and then covered in earth or cement/concrete. OSP cable types use special coatings to protect against UV and abrasion and are often gel-filled to protect against temperature extremes and damp conditions. Direct burial cable may also need to be armored to protect against chewing by rodents. ____________________________________________________________________ 5.3.10 Optical Cabling Copper wire carries electrical signals, which are sensitive to interference and attenuation. The light pulses generated by lasers and LEDs are not susceptible to interference and suffer less from attenuation. Consequently, optical cabling can support much higher bandwidth links, measured in multiple gigabits or terabits per second, and longer cable runs, measured in miles rather than feet. A fiber optic strand A fiber optic strand with a protective outer jacket, strength fibers, and a central core. Image by atrush © 123RF.com) An optical fiber consists of an ultra-fine core of glass to convey the light pulses. The core is surrounded by glass or plastic cladding, which guides the light pulses along the core. The cladding has a protective coating called the "buffer." The fiber optic cable is contained in a protective jacket and terminated by a connector. Fiber optic cables fall into two broad categories: single-mode and multi-mode: Single-mode fiber (SMF) has a small core (8–10 microns) and is designed to carry a long wavelength (1,310 or 1,550 nm) infrared signal, generated by a high-power, highly coherent laser diode. Single-mode cables support data rates up to 10 Gbps or better and cable runs of many kilometers, depending on the quality of the cable and optics. Multimode fiber (MMF) has a larger core (62.5 or 50 microns) and is designed to carry a shorter wavelength infrared light (850 nm or 1,300 nm). MMF uses less expensive and less coherent LEDs or vertical cavity surface emitting lasers (VCSELs) and consequently is less expensive to deploy than SMF. However, MMF does not support such high signaling speeds or long distances as single-mode and so is more suitable for LANs than WANs. The core of a fiber optic connector is a ceramic or plastic ferrule that ensures continuous reception of the light signals. Several connector form factors are available: Straight-tip connector (ST) is a bayonet-style connector that uses a push-and-twist locking mechanism; it is used mostly on older multi-mode networks. Subscriber connector (SC) has a push/pull design that allows for simpler insertion and removal than fiber channel (FC) connector. There are simplex and duplex versions, though the duplex version is just two connectors clipped together. It can be used for single- or multi-mode. Lucent connector (LC) is a small form factor connector with a tabbed push/pull design. LC is similar to SC, but the smaller size allows for higher port density. This connector is also sometimes referred to as little-connector or local-connector. Patch cord with duplex SC format connectors (left) and LC connectors (right) A yellow patch cord cable with S C format connectors and L C connectors. Image by YANAWUT SUNTORNKIJ © 123RF.com. Patch cords for fiber optic can come with the same connector on each end (ST-ST, for instance) or a mix of connectors (ST-SC, for instance). Fiber optic connectors are quite easy to damage and should not be repeatedly plugged in and unplugged. Unused ports and connectors should be covered by a dust cap to minimize the risk of contamination. ____________________________________________________________________ 5.3.11 Coaxial Cabling Coaxial cable is a different type of copper cabling that also carries electrical signals. Where twisted pair uses balancing to cancel out interference, coax uses two conductors that share the same axis. The core signal conductor is enclosed by plastic insulation (dielectric), and then a second wire mesh conductor serves both as shielding from EMI and as a ground. Detailed layers of a coaxial cable A coaxial cable with a black outer sheath, braided shielding, foil insulation, and a central copper conductor. Image by destinacigdem © 123RF.com Coax is now mostly used for CCTV installations and as patch cable for Cable Access TV (CATV) and broadband cable modem. Coax for CATV installations is typically terminated using a screw-down F-type connector. F-type coaxial connector A coaxial cable with a F-type connector. Image © 123RF.com Bayonet Neill-Concelman (BNC) Connector Image of a Bayonet Neill-Concelman (BNC) Connector Description Bayonet Neill-Concelman (BNC) is a coaxial cable connector that uses a bayonet coupling mechanism to connect coaxial cables, typically found in cabling for video, radio, and television. ____________________________________________________________________ ____________________________________________________________________ 5.4 Wireless Networking Types ____________________________________________________________________ 5.4.1 Access Points Coaxial cable is a different type of copper cabling that also carries electrical signals. Where twisted pair uses balancing to cancel out interference, coax uses two conductors that share the same axis. The core signal conductor is enclosed by plastic insulation (dielectric), and then a second wire mesh conductor serves both as shielding from EMI and as a ground. Detailed layers of a coaxial cable A coaxial cable with a black outer sheath, braided shielding, foil insulation, and a central copper conductor. Image by destinacigdem © 123RF.com Coax is now mostly used for CCTV installations and as patch cable for Cable Access TV (CATV) and broadband cable modem. Coax for CATV installations is typically terminated using a screw-down F-type connector. F-type coaxial connector A coaxial cable with a F-type connector. Image © 123RF.com Bayonet Neill-Concelman (BNC) Connector Image of a Bayonet Neill-Concelman (BNC) Connector Description Bayonet Neill-Concelman (BNC) is a coaxial cable connector that uses a bayonet coupling mechanism to connect coaxial cables, typically found in cabling for video, radio, and television. ____________________________________________________________________ 5.4.2 Frequency Bands Every Wi-Fi device operates on a specific radio frequency range within an overall frequency band. Channels Each wireless frequency band is split into a series of smaller ranges referred to as a channel. These channels essentially act as lanes through the frequency band, allowing wireless networks to operate on the same wireless band without interfering with each other. The width or size of each channel is determined by the frequency band and the access point configuration. All channels are the same width, but some wireless standards allow for channels to be bonded together, creating a wider channel. The larger the channel width, the more data that can flow down it. Wireless Frequency Bands The three main frequency bands in use by wireless networks are: The 2.4 GHz standard is better at propagating through solid surfaces, giving it the longest signal range. However, the 2.4 GHz band does not support a high number of individual channels and is often congested with other Wi-Fi networks and even other types of wireless technology, such as Bluetooth®. Also, microwave ovens work at frequencies in the 2.4 GHz band. Consequently, with the 2.4 GHz band, there is increased risk of interference, and the maximum achievable data rates are typically lower than with 5 GHz. The 5 GHz standard is less effective at penetrating solid surfaces, and so does not support the maximum ranges achieved with 2.4 GHz standards, but the band supports more individual channels and suffers less from congestion and interference, meaning it supports higher data rates at shorter ranges. The 6 GHz standard is the latest wireless band that can be used by wireless networks. This standard is even less effective at penetrating solid surfaces than the 5 GHz band, so therefore does not achieve the longer ranges of the 2.4 GHz and 5 GHz bands. However, it is much faster than both of the other bands. Since this is a newer band, there is typically less congestion, which results in a more stable and reliable connection. The nominal indoor range for Wi-Fi is 45 m (150 feet) over 2.4 GHz, 30 m (100 feet) over 5 GHz, and 15 m (50 feet) over 6 GHz. Depending on the wireless standard used, building features that may block the signal, and interference from other radio sources, clients are only likely to connect at full speed from a third to a half of those distances. Frequency bands are typically regulated in terms of radio operation, and there is a restriction on power output, which is another factor in limiting range. ____________________________________________________________________ 5.4.3 IEEE 802.11a The IEEE 802.11a standard uses the 5 GHz frequency band only. The data encoding method allows a maximum data rate of 54 Mbps. The 5 GHz band is subdivided into 23 non-overlapping channels, each of which is 20 MHz wide. The exact use of channels can be subject to different regulations in different countries. Regulatory impacts also include a limit on power output, constraining the range of Wi-Fi devices. Devices operating in the 5 GHz band must implement dynamic frequency selection to prevent Wi-Fi signals from interfering with nearby radar and satellite installations. Unlicensed National Information Infrastructure (U-NII) sub-bands form the 20 MHz channels used in the 5 GHz frequency band. Each sub-band is 5 MHz wide, so the Wi-Fi channels are spaced in intervals of four to allow 20 MHz bandwidth. Channels within the DFS range will be disabled if the access point detects radar signals U-N I I sub bands U-N I I-1, U-N I I-2, U-N I I-2 Extended, and U-N I I-3 from the 20 Mega hertz channels. Description ____________________________________________________________________ 5.4.4 IEEE 802.11b/g The IEEE 802.11b standard uses the 2.4 GHz frequency band and was released in parallel with 802.11a. The signal encoding methods used by 802.11b are inferior to 802.11a and support a nominal data rate of just 11 Mbps. The 2.4 GHz band is subdivided into up to 14 channels, spaced at 5 MHz intervals from 2,412 MHz up to 2,484 MHz. Because the spacing between each channel is only 5 MHz and 802.11b uses channels that are 22 MHz wide, 802.11b channels overlap quite considerably. This means that interference is going to occur unless you use one of the three non-overlapping channels (1, 6, and 11). Also, in the Americas, regulations permit the use of channels 1–11 only, while in Europe, channels 1–13 are permitted, and in Japan, all 14 channels are permitted. Channel overlap in the 2.4 GHz band A table and a graph illustrating 2.4 gigahertz Wi-Fi frequencies and channel overlaps. Description The IEEE 802.11g standard offered a relatively straightforward upgrade path from 802.11b. 802.11g uses the same encoding mechanism and 54 Mbps rate as 802.11a but in the 2.4 GHz band used by 802.11b. This made it straightforward for vendors to design 802.11g devices that could offer backward support for legacy 802.11b clients. One key difference between 802.11b and 802.11g is the channel width. 802.11b uses a 22 MHz channel width, whereas 802.11g uses a 20 MHz channel width. This is due to the modulation technique that each standard uses. Modulation is the process or technique used to modify a radio wave so it can carry data. 802.11b uses the Direct-Sequence Spread Spectrum (DSSS) modulation technique. DSSS spreads the signal across a wider channel (22 MHz) to improve resistance to interference. 802.11g uses the Orthogonal Frequency-Division Multiplexing (OFDM) modulation technique. OFDM is more efficient, which allows more data to be sent across a smaller channel (20 MHz). Even though 802.11g uses a smaller channel width, the channel in the 2.4 GHz range is the same just to keep things compatible between the two standards. ____________________________________________________________________ 5.4.5 802.11n The IEEE 802.11n standard introduced several improvements to increase bandwidth. It can work over both 2.4 GHz and 5 GHz. Each band is implemented by a separate radio. An access point or adapter that can support simultaneous 2.4 GHz and 5 GHz operation is referred to as "dual band." Some older client smartphone adapters support only a 2.4 GHz radio. The 802.11n standard allows two adjacent 20 MHz channels to be combined into a single 40 MHz channel, referred to as "channel bonding." Due to the restricted channel layout of 2.4 GHz on a network with multiple APs, channel bonding is a practical option only in the 5 GHz band. However, note that 5 GHz channels are not necessarily contiguous, and the use of some channels may be blocked if the access point detects a radar signal. 802.11n 40 MHz bonded channel options in the 5 GHz band. The center channel number is used to identify each bonded channel U-N I I sub bands U-N I I-1, U-N I I-2, U-N I I-2 Extended, and U-N I I-3 from the 20 and 40 Mega hertz channels. Description The other innovation introduced with 802.11n increases reliability and bandwidth by multiplexing signal streams from 2–3 separate antennas. This technology is referred to as multiple input multiple output (MIMO). The antenna configuration is represented as 1x1, 2x2, or 3x3 to indicate the number of transmit and receive antennas available to the radio. The nominal data rate for 802.11n is 72 Mbps per stream or 150 Mbps per stream for a 40 MHz bonded channel, and 802.11n access points are marketed using Nxxx designations, where xxx is the nominal bandwidth. As an example, an N600 2x2 access point can allocate a bonded channel to two streams for a data rate of 300 Mbps, and if it does this simultaneously on both its 2.4 GHz and 5 GHz radios, the bandwidth of the access point could be described as 600 Mbps. In recent years, Wi-Fi standards have been renamed with simpler digit numbers; 802.11n is now officially designated as Wi-Fi 4. ____________________________________________________________________ 5.4.6 Wi-Fi 5 and Wi-Fi 6 The Wi-Fi 5 (or 802.11ac) and Wi-Fi 6 ( 802.11ax ) standards continue the development of Wi-Fi technologies to increase bandwidth and support modern networks. Wi-Fi 5 (802.11ac) Wi-Fi 5 is designed to work only in the 5 GHz band. A dual-band access point can use its 2.4 GHz radio to support clients on legacy standards (802.11g/n). A tri-band access point has one 2.4 GHz radio and two 5 GHz radios. Wi-Fi 5 allows up to eight streams, though in practice, most Wi-Fi 5 access points only support 4x4 streams. A single stream over an 80 MHz channel has a nominal rate of 433 Mbps. Wi-Fi 5 also allows wider 80 and 160 MHz bonded channels. 80 and 160 MHz bonded channel options for Wi-Fi 5 U-N I I sub bands U-N I I-1, U-N I I-2, U-N I I-2 Extended, and U-N I I-3 from the 20, 40, 80, and 160 Mega hertz channels. Description Wi-Fi 5 access points are marketed using AC values, such as AC5300. The 5300 value is made up of the following: 1,000 Mbps over a 40 MHz channel with 2x2 streams on the 2.4 GHz radio. 2,166 Mbps over an 80 MHz bonded channel with 4x4 streams on the first 5 GHz radio. 2,166 Mbps on the second 5 GHz radio. Note: You'll notice that, given 802.11n 150 Mbps per stream (40 MHz channels) and 802.11ac 433 Mbps per stream (80 MHz channels), none of those values can be made to add up. The labels are only useful as relative performance indicators. Multiuser MIMO (MU-MIMO) In basic 802.11 operation modes, bandwidth is shared between all stations. An AP can communicate with only one station at a time; multiple station requests go into a queue. Wi-Fi 5 products partially address this problem using multiuser MIMO. In Wi-Fi 5, downlink MU-MIMO (DL MU-MIMO) allows the access point to use its multiple antennas to send data to up to four clients simultaneously. Wi-Fi 6 (802.11ax) Wi-Fi 6 improves the per-stream data rate over an 80 MHz channel to 600 Mbps. As with Wi-Fi 5, products are branded using the combined throughput of all radios. For example, AX6000 claims nominal rates of 1,148 Mbps on the 2.4 GHz radio and 4,804 Mbps over 5 GHz. Wi-Fi 6 works in both the 2.4 GHz and 5 GHz bands. The Wi-Fi 6e standard adds support for a new 6 GHz frequency band. 6 GHz has less range but more frequency space, making it easier to use 80 and 160 MHz channels. Where Wi-Fi 5 supports up to four simultaneous clients over 5 GHz only, Wi-Fi 6 can support up to eight clients, giving it better performance in congested areas. Wi-Fi 6 also adds support for uplink MU-MIMO, which allows MU-MIMO capable clients to send data to the access point simultaneously. Wi-Fi 6 introduces another technology to improve simultaneous connectivity called orthogonal frequency division multiple access. OFDMA can work alongside MU-MIMO to improve client density - sustaining high data rates when more stations are connected to the same access point. ____________________________________________________________________ 5.4.7 Wi-Fi 7 (802.11be) Wi-Fi 7 operates in the 2.4 GHz, 5 GHz, and 6 GHz bands. Wi-Fi 7 utilizes channels that are 320 MHz wide when operating the 6 GHz range, allowing for much faster data transfer speeds up to 46 Gbps. Wi-Fi 7 provides support for Multi-Link Operation (MLO), which allows devices to connect and send data over multiple bands (2.4 GHz, 5 GHz, and 6 GHz) or channels to reduce latency and improve throughput. Another key feature of Wi-Fi 7 is the ability to use Multi-Resource Units (MRUs). Each channel in the 6 GHz range is broken down into smaller channels called MRUs, which can all be different sizes based on the needs of the network. The access point dynamically allocates MRUs to different devices based on their data requirements. Devices with higher bandwidth needs may receive more MRUs, while devices with lower needs may receive fewer MRUs. ____________________________________________________________________ 5.4.8 Wireless LAN Installation Considerations Clients identify an infrastructure WLAN through the network name or service set identifier (SSID) configured on the access point. An SSID can be up to 32 bytes in length and, for maximum compatibility, should only use ASCII letters and digits plus the hyphen and underscore characters. Configuring an access point A screenshot of the T P-Link Archer V R 900 router's web-based interface displays the Wireless Settings page under the Advanced tab. Screenshot courtesy of TP-Link. Description When configuring an access point, you need to choose whether to use the same or different network names for both frequency bands. If you use the same SSID, the access point and client device will use a probe to select the band with the strongest signal. If you configure separate names, the user can choose which network and band to use. For each frequency band, you also need to select the operation mode. This determines compatibility with older standards and support for legacy client devices. Supporting older devices can reduce performance for all stations. Finally, for each frequency band, you need to configure the channel number and whether to use channel bonding. If there are multiple access points whose ranges overlap, they should be configured to use nonoverlapping channels to avoid interference. An access point can be left to autoconfigure the best channel, but this does not always work well. You can configure wide channels (bonding) for more bandwidth, but this has the risk of increased interference if there are multiple nearby wireless networks. Channel bonding may only be practical in the 5 GHz band, depending on the wireless site design. Note: Along with the Wi-Fi frequency band and channel settings, you should also configure security parameters to control who is allowed to connect. ____________________________________________________________________ 5.4.9 Wi-Fi Analyzers To determine the best channel layout and troubleshoot wireless network performance, you need to measure the signal strength of the different networks using each channel. This can be accomplished using a Wi-Fi analyzer. A Wi-Fi analyzer can be either hardware or software. A software Wi-Fi analyzer can be installed on a laptop or smartphone. It will record statistics for the AP that the client is currently associated with and detect any other access points in the vicinity. Wireless signal strength is measured in decibel units. Signal strength is represented as the ratio of a measurement to 1 milliwatt (mW), where 1 mW is equal to 0 dBm. Because 0 dBm is 1 mW, a negative value for dBm represents a fraction of a milliwatt. For example, -30 dBm is 0.001 mW; -60 dBm is 0.000001 mW. Wi-Fi devices are all constrained by regulations governing frequency band use and output only small amounts of power. When you are measuring signal strength, dBm values closer to zero represent better performance. A value around -65 dBm represents a good signal, while anything over -80 dBm is likely to suffer packet loss or be dropped. Note: The dB units express the ratio between two values using a logarithmic scale. A logarithmic scale is nonlinear, so a small change in value represents a large change in the performance measured. For example, +3 dB means doubling, while -3 dB means halving. The comparative strength of the data signal to the background noise is called the signal-to-noise ratio. Noise is also measured in dBm, but here values closer to zero are less welcome, as they represent higher noise levels. For example, if signal is ‑65 dBm and noise is ‑90 dBm, the SNR is the difference between the two values, expressed in dB (25 dB). If noise is -80 dBm, the SNR is 15 dB and the connection will be much, much worse. In the following screenshot, a Wi-Fi analyzer is being used to report nearby networks and channel configurations. The "home" network is supported by two access points using the same SSID for both bands. They are configured to use channels 6 and 11 on the 2.4 GHz band, with the stronger signal on channel 6, indicating the closer access point. On the 5 GHz band, only the signal on channel 36 is detected by this client. This is because 5 GHz has less range than 2.4 GHz. The blurred networks belong to other owners and have much weaker signals. Also, note from the status bar that the client adapter supports Wi-Fi 6 (ax), but the access points only support b/g/n/ac (shown in the mode column). Metageek inSSIDer Wi-Fi analyzer software showing nearby access points An inSSIDer webpage. MetaGeek, LLC. © Copyright 2005-2025. Description ____________________________________________________________________ 5.4.10 Long-Range Fixed Wireless Wireless technology can be used to configure a bridge between two networks. This can be a more cost-effective and practical solution than laying cable. However, regulation of the radio spectrum means that the transmitters required to cover long distances must be carefully configured. These solutions are referred to as long-range fixed wireless. Point-to-point line-of-sight fixed wireless uses ground-based high-gain microwave antennas that must be precisely aligned with one another. "High-gain" means that the antenna is strongly directional. Each antenna is pointed directly at the other and can transmit signals at ranges of up to about 30 miles as long as they are unobstructed by physical objects. The antennas themselves are typically affixed to the top of tall buildings or mounted on tall poles to reduce the risk of obstructions. Long-range fixed wireless can be implemented using licensed or unlicensed frequency spectrum. Licensed means that the network operator purchases the exclusive right to use a frequency band within a given geographical area from the regulator. The US regulator is the Federal Communications Commission (FCC). If any interference sources are discovered, the network operator has the legal right to get them shut down. Unlicensed spectrum means the operator uses a public frequency band, such as 900 MHz, 2.4 GHz, and 5 GHz. Anyone can use these frequencies, meaning that interference is a risk. To minimize the potential for conflicts, power output is limited by regulatory requirements. A wireless signal’s power has three main components: Transmit power is the basic strength of the radio, measured in dBm. Antenna gain is the amount that a signal is boosted by directionality - focusing the signal in a single direction rather than spreading it over a wide area. Gain is measured in decibels per isotropic. Effective isotropic radiated power (EIRP) is the sum of transmit power and gain, expressed in dBm. Lower frequencies that propagate farther have stricter power limits than higher frequencies. However, higher EIRPs are typically allowed for highly directional antennas. For example, in the 2.4 GHz band, each 3 dBi increase in gain can be compensated for by just a 1 dBm reduction in transmit power. This allows point-to-point wireless antennas to work over longer ranges than Wi-Fi APs. ____________________________________________________________________ 5.4.11 Bluetooth, RFID, and NFC Wi-Fi is used for networking computer hosts together, but other types of wireless technology are used to implement personal area networking (PAN). Bluetooth Bluetooth is used to connect peripheral devices to PCs and mobiles and to share data between two systems. Many portable devices, such as smartphones, tablets, wearable tech, audio speakers, and headphones, now use Bluetooth connectivity. Bluetooth uses radio communications and supports speeds of up to 3 Mbps. Adapters supporting version 3 or 4 of the standard can achieve faster rates (up to 24 Mbps) through the ability to negotiate an 802.11 radio link for large file transfers. The earliest Bluetooth version supports a maximum range of 10 m (30 feet), while newer versions support a range of over 100 feet, though signal strength will be weak at this distance. Bluetooth devices can use a pairing procedure to authenticate and exchange data securely. Bluetooth pairing A smartphone in the foreground shows the Bluetooth settings screen. Image © 123RF.com Description Version 4 introduced a Bluetooth Low Energy (BLE) variant of the standard. BLE is designed for small battery-powered devices that transmit small amounts of data infrequently. A BLE device remains in a low-power state until a monitor application initiates a connection. BLE is not backward compatible with "classic" Bluetooth, though a device can support both standards simultaneously. Bluetooth 5 is the latest Bluetooth standard. Bluetooth 5 offers a range of up to 240 m (800 ft) which is about 4 times the range for Bluetooth 4. Bluetooth 5 also provides twice the speed of Bluetooth 4 and 8 times the messaging capacity. This translates to quicker file transfers, smoother streaming, and improved responsiveness in applications that require real-time data exchange. Bluetooth 5 improves power consumption over other versions of Bluetooth. Radio Frequency Identification (RFID) Radio Frequency ID is a means of identifying and tracking objects using specially encoded tags. When an RFID reader scans a tag, the tag responds with the information programmed into it. A tag can be either an unpowered, passive device that only responds when scanned at close range (up to about 25 m) or a powered, active device with a range of 100 m. Passive RFID tags can be embedded in stickers and labels to track parcels and equipment. RFID is also used to implement some types of access badges to operate electronic locks. Near Field Communications Near Field Communication is a peer-to-peer version of RFID. In other words, an NFC device can work as both tag and reader to exchange information with other NFC devices. NFC normally works at up to two inches (6 cm) at data rates of 106, 212, and 424 Kbps. NFC is mostly used for contactless payment readers, security ID tags, and shop shelf-edge labels for stock control. It can also be used to configure other types of connections such as pairing Bluetooth devices. ____________________________________________________________________ ____________________________________________________________________ ____________________________________________________________________ /ENDOFCHAPTER