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Networking and Wireless FAQs

Industrial networks have to keep running when a cable is cut or a switch loses power. These FAQs explain Ethernet, PoE, network topologies, QoS and TSN, fibre and SFP, plus Wi-Fi, cellular and bonding for connected and mobile systems.

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Topics 12

NETWORKING · CELLULAR

What Is a Modem?

A modem, short for modulator-demodulator, converts digital data into a signal that can travel over a phone line, cable, fibre or mobile network, and converts the incoming signal back. It connects a site or device to an internet provider. In industrial computers the modem is usually a 4G or 5G module fitted inside the system.

6 MIN

NETWORKING · TOPOLOGY

What Is Star Topology?

Star topology is a network layout in which every device connects by its own cable to one central device, today almost always an Ethernet switch. Traffic between any two devices passes through the centre. A broken cable affects only one device, but the central switch is a single point of failure for everything connected to it.

6 MIN

NETWORKING · ROUTERS

What Does a Router Do?

A router connects separate networks and forwards data between them by IP address. On a home or business site it links the local network to the internet, shares one public address through NAT, hands out local addresses with DHCP and filters traffic with a firewall. Industrial routers do the same job on DIN rail, often over 4G or 5G.

6 MIN

NETWORKING · TOPOLOGY

What Is Mesh Topology?

Mesh topology is a network layout in which devices connect to several others, so traffic has more than one path between any two points. In a full mesh every node links to every other node. In a partial mesh only some do. Meshes are used where a single failed link or node must not cut anyone off.

6 MIN

INDUSTRIAL PROTOCOLS · MACHINE TOOLS

What Is MTConnect?

MTConnect is an open, royalty-free standard for reading data from CNC machine tools and other manufacturing equipment. An agent publishes each machine’s state, program, spindle, axis and alarm data as XML or JSON over HTTP, using a common vocabulary, so monitoring software can read different brands of machine the same way.

6 MIN

SECURITY · NETWORK ARCHITECTURE

What Is the Purdue Model?

The Purdue model is a reference architecture that divides an industrial network into levels, from sensors and actuators at Level 0 up to business IT and the internet at Levels 4 and 5, with an industrial DMZ between them. It is widely used to plan network segmentation for industrial control systems.

6 MIN

SECURITY · INDUSTRIAL NETWORKS

What Is OT Security?

OT security is the protection of the operational technology that monitors and controls physical processes: PLCs, SCADA, HMIs, industrial PCs and the networks that join them. Safety and availability come first, so controls are chosen to keep the process running, guided by standards such as IEC 62443 and NIST SP 800-82.

6 MIN

SERIAL COMMUNICATION · NETWORKING

What Is a Serial to Ethernet Converter?

A serial to Ethernet converter, also called a serial device server, connects an RS-232, RS-422 or RS-485 device to an Ethernet network. It carries the serial data inside TCP or UDP packets, so software on a remote computer can reach the device through a virtual COM port or a network socket instead of a local serial cable.

6 MIN

INDUSTRIAL PROTOCOLS · IIOT

What Is Sparkplug B?

Sparkplug B is an open specification that defines how industrial devices and applications use MQTT. It fixes the topic structure, encodes data as typed, time-stamped metrics using Protocol Buffers, and adds birth and death messages so a SCADA or IIoT host always knows which devices are online and whether their data is current.

4 MIN

INDUSTRIAL PROTOCOLS · GATEWAYS

What Is a Modbus Gateway?

A Modbus gateway converts between Modbus RTU or ASCII on a serial line, usually RS-485, and Modbus TCP on Ethernet. It lets a SCADA system, PLC or edge computer on the network read and write serial meters, drives and controllers as if they were Modbus TCP devices, using the address byte in each request to reach the right device.

6 MIN

INDUSTRIAL PROTOCOLS · SCADA AND TELEMETRY

What Is DNP3?

DNP3 (Distributed Network Protocol 3) is an open SCADA protocol, standardised as IEEE 1815, that links a control centre master to outstations such as RTUs and protection relays. It runs over serial lines or TCP/IP, reports changes as time-stamped events, lets outstations send unsolicited reports and is widely used by electricity and water utilities.

6 MIN

NETWORKING · TIME SYNCHRONISATION

What Is Precision Time Protocol (PTP)?

Precision Time Protocol (PTP), defined in IEEE 1588, synchronises the clocks of devices on a network to a single reference clock, called the grandmaster. With hardware timestamping in the network interfaces and switches, PTP typically aligns clocks to within a microsecond or better, far tighter than NTP, which is why it is used in industrial automation, substations, broadcast and telecoms.

7 MIN

NETWORKING · SWITCH SECURITY

What Is DHCP Snooping?

DHCP snooping is a managed switch feature that blocks rogue DHCP servers. The switch only accepts DHCP offers on ports you mark as trusted, drops them everywhere else, and records which IP address each device was given on which port. That binding table also feeds IP source guard and dynamic ARP inspection.

6 MIN

NETWORKING · ACCESS CONTROL

What Is 802.1X Authentication?

802.1X is the IEEE standard for port-based network access control. A switch or wireless access point keeps a port closed until the connected device proves its identity, usually with a certificate or password checked by a RADIUS server. Only then does the port pass normal traffic, so an unknown device plugged into a wall socket gets no network access.

7 MIN

NETWORKING · MONITORING

What Is Port Mirroring?

Port mirroring is a managed switch feature that copies the traffic on one or more ports or VLANs to a separate monitoring port. A packet analyser, intrusion detection sensor or recorder on that port sees the traffic without sitting in its path. Cisco calls it SPAN; remote versions such as RSPAN carry the copy across the network.

6 MIN

NETWORKING · GATEWAY REDUNDANCY

What Is VRRP (Virtual Router Redundancy Protocol)?

VRRP (Virtual Router Redundancy Protocol) is an open IETF standard that lets two or more routers or Layer 3 switches share one virtual default gateway address. One device is active and forwards traffic; if it fails, a backup takes over the same IP and MAC address within seconds, so hosts keep routing without any change to their settings.

6 MIN

NETWORKING · INDUSTRIAL ETHERNET

What Is Network Redundancy?

Network redundancy means building a network with spare paths, devices and power feeds, so traffic keeps flowing when a cable, switch, gateway or supply fails. A protocol such as RSTP, ERPS, PRP or VRRP decides which path is used and how quickly the backup takes over, from tens of seconds down to zero frame loss.

6 MIN

INDUSTRIAL I/O · NETWORKS

What Is Fieldbus?

Fieldbus is the family of industrial digital networks that connect controllers such as PLCs to field devices: sensors, actuators, drives and valves. One shared cable replaces a separate wire pair per signal. PROFIBUS, Foundation Fieldbus, Modbus RTU, CANopen and DeviceNet are fieldbuses, standardised internationally in IEC 61158 and IEC 61784.

7 MIN

CABLES · ETHERNET

T568A vs T568B: What Is the Difference?

T568A and T568B are the two colour codes for wiring an RJ45 plug or socket, both defined in the ANSI/TIA-568 cabling standard. The only difference is that the orange and green pairs swap places. Both perform identically; what matters is using the same scheme at both ends of a straight-through cable.

6 MIN

NETWORKING · INDUSTRIAL ETHERNET

What Is a Broadcast Storm?

A broadcast storm is a flood of broadcast or multicast frames that builds up until it uses most of a network’s capacity, so normal traffic stops getting through. The usual cause is a switching loop, where frames circle endlessly and multiply. Loop protection such as RSTP and per-port storm control on managed switches prevent or contain it.

6 MIN

NETWORKING · ETHERNET PERFORMANCE

What Are Jumbo Frames?

Jumbo frames are Ethernet frames that carry more than the standard 1,500 bytes of payload, usually up to 9,000 bytes. Fewer, larger frames cut header overhead and the number of packets a computer has to process, which helps bulk transfers such as GigE Vision cameras and storage. Every device on the path must support the same size.

6 MIN

NETWORKING · INDUSTRIAL ETHERNET

What Is LLDP (Link Layer Discovery Protocol)?

LLDP (Link Layer Discovery Protocol) is a vendor-neutral Layer 2 protocol, defined in IEEE 802.1AB, that lets a network device advertise its identity and capabilities to the devices directly connected to it. Switches store what they hear in a neighbour table, which management software uses to map the network, find which port a device is on and negotiate PoE power.

5 MIN

NETWORKING · MULTICAST

What Is IGMP Snooping?

IGMP snooping is a switch feature that listens to the IGMP messages hosts send when they join or leave a multicast group. The switch records which ports want each group and forwards multicast traffic only to those ports, instead of flooding every port like a broadcast. It keeps multicast video and control traffic off links that do not need it.

6 MIN

NETWORKING · INDUSTRIAL ETHERNET

What Is RSTP (Rapid Spanning Tree Protocol)?

RSTP (Rapid Spanning Tree Protocol) is the faster version of Spanning Tree Protocol, first published as IEEE 802.1w. It keeps redundant Ethernet links loop-free like STP, but neighbouring switches negotiate directly instead of waiting on timers, so recovery after a link failure typically takes around a second or less instead of 30 to 50 seconds.

6 MIN

NETWORKING · INDUSTRIAL ETHERNET

What Is Spanning Tree Protocol (STP)?

Spanning Tree Protocol (STP) is a Layer 2 network protocol, defined in IEEE 802.1D, that stops loops in Ethernet networks with redundant links. Switches elect a root bridge, work out the lowest-cost path to it and block every other path, then unblock a backup link if the active one fails.

8 MIN

INDUSTRIAL PROTOCOLS · INDUSTRIAL ETHERNET

What Is EtherNet/IP?

EtherNet/IP (Ethernet Industrial Protocol) is an industrial network protocol that carries the Common Industrial Protocol (CIP) over standard Ethernet and TCP/IP. Managed by ODVA, it links PLCs, remote I/O, drives and HMIs, using TCP for configuration and UDP for real-time I/O. The IP means Industrial Protocol, not Internet Protocol.

6 MIN

INDUSTRIAL PROTOCOLS · IIOT

What Is OPC UA?

OPC UA (OPC Unified Architecture) is an open standard, IEC 62541, for exchanging data securely between industrial machines, controllers and software on any operating system. Servers publish a browsable information model that describes what each value means, and clients read, write or subscribe to it, with certificates and encryption built in.

6 MIN

INDUSTRIAL I/O · CONTROL SYSTEMS

What Is Remote I/O?

Remote I/O is input and output hardware installed near the sensors and actuators it serves and connected to the controller over a network or fieldbus, rather than wired back to the controller’s own rack. It cuts field wiring on large machines and sites, and it works with PLCs, industrial PCs and gateways.

6 MIN

NETWORKING · SWITCHING AND REDUNDANCY

What Is Link Aggregation?

Link aggregation combines two or more parallel Ethernet links between the same two devices into one logical link, called a LAG. It adds bandwidth and keeps traffic flowing if one link fails. LACP, defined in IEEE 802.1AX (originally 802.3ad), negotiates and monitors the bundle; a static LAG skips the negotiation.

7 MIN

NETWORKING · NETWORK MANAGEMENT

What Is SNMP?

SNMP (Simple Network Management Protocol) is the standard way to monitor and manage networked devices. A manager polls agents on switches, routers, UPSs and computers for values held in a MIB, such as port status, traffic and temperature, and agents send traps when something changes. It runs over UDP: port 161 for polling, 162 for traps.

7 MIN

NETWORKING · IP ADDRESSING

What Is APIPA?

APIPA (Automatic Private IP Addressing) is how a device set to use DHCP gives itself an address when no DHCP server answers. It picks an address in 169.254.0.0/16, checks that no other device is using it, and can then talk to devices on the same local network, but not through a router or to the internet.

7 MIN

NETWORKING · PORTS AND PROTOCOLS

What Is a TCP Port?

A TCP port is a 16-bit number, from 0 to 65535, that tells a device which application a TCP connection is for. The IP address finds the device and the port finds the service: Modbus TCP listens on 502, OPC UA on 4840 and HTTPS on 443. UDP has its own separate set of port numbers.

7 MIN

NETWORKING · TRANSPORT PROTOCOLS

TCP vs UDP: What Is the Difference?

TCP is connection-oriented: it sets up a session, numbers every byte, resends anything lost and delivers data in order. UDP is connectionless: it sends independent datagrams with no handshake, retransmission or ordering, so it has less overhead and lower latency. Use TCP when every byte must arrive, and UDP when late data is worthless.

7 MIN

NETWORKING · ETHERNET STANDARDS

What Is 1000BASE-T?

1000BASE-T is Gigabit Ethernet over copper twisted pair: 1,000 Mb/s on all four pairs of Cat 5e or better cable, up to 100 m per link, defined in IEEE 802.3ab. In the IEEE naming scheme the number is the speed in Mb/s, BASE means baseband signalling and the suffix names the medium.

7 MIN

NETWORKING · ACCELERATION

What Is a SmartNIC?

A SmartNIC is a network interface card with its own programmable processing, such as an ASIC, FPGA or Arm cores, that takes networking, security and storage work off the server’s CPU. It handles tasks like virtual switching, encryption and RDMA at line rate. The most capable SmartNICs are called DPUs.

6 MIN

INDUSTRIAL AUTOMATION · CONTROL SYSTEMS

What Is SCADA?

SCADA (supervisory control and data acquisition) is a control system that gathers data from PLCs, RTUs and sensors across a plant or a wide area, shows it to operators, raises alarms, logs history and lets staff send commands back to the equipment. Water, power, oil and gas, rail and factories use it to supervise processes they cannot watch by hand.

7 MIN

INDUSTRIAL IOT · CONNECTED OPERATIONS

What Is the Industrial Internet of Things (IIoT)?

The industrial internet of things (IIoT) is the use of connected sensors, machines and controllers in industry, linked through gateways and networks to software that stores and analyses their data. It lets factories, utilities, transport and energy sites monitor equipment remotely, predict failures, cut energy use and improve quality without someone reading each gauge.

7 MIN

COMPUTING · CLIENT DEVICES

What Is a Zero Client?

A zero client is a stateless desktop device with no general-purpose operating system and no local user data. It connects straight to a virtual desktop or remote session on a server through one display protocol, such as PCoIP, Blast or HDX, then shows the screen and sends keyboard, mouse and USB input back.

6 MIN

INDUSTRIAL NETWORKS · IT AND OT

IT vs OT: What Is the Difference?

IT (information technology) manages data: servers, PCs, networks and business software. OT (operational technology) monitors and controls physical equipment: PLCs, SCADA, robots and building controls. IT puts data confidentiality first and changes fast; OT puts safety and uptime first, runs for decades and changes only in planned outages.

10 MIN

EDGE COMPUTING · ARCHITECTURE

Fog Computing vs Edge Computing: What Is the Difference?

Edge computing processes data on or right beside the device that creates it, such as a camera, machine or vehicle. Fog computing adds a layer between the edge and the cloud: local servers or gateways that collect data from many edge devices across a site, filter and analyse it, then pass only what matters to the cloud.

6 MIN

DEFENCE · SIGNALS INTELLIGENCE

What Is SIGINT?

SIGINT, or signals intelligence, is intelligence gathered by intercepting and analysing signals. It covers communications intelligence (COMINT), taken from messages between people, and electronic intelligence (ELINT), taken from non-communication emissions such as radar. GCHQ in the UK and the NSA in the US lead it, alongside military teams on aircraft, ships and ground stations.

7 MIN

DEFENCE · COMMAND AND CONTROL

What Is C4ISR?

C4ISR stands for command, control, communications, computers, intelligence, surveillance and reconnaissance. It is the military term for the networked systems that gather information from sensors, turn it into a shared picture and pass decisions to forces. C5ISR adds cyber, and UK forces often use C4ISTAR, which adds target acquisition.

7 MIN

CONNECTORS · RF AND ANTENNAS

What Is an MMCX Connector?

An MMCX connector is a micro-miniature coaxial connector that snaps on and can rotate a full 360 degrees once mated. It is usually 50 ohm, works from DC to around 6 GHz and is rated for around 500 mating cycles. It is used for GNSS, Wi-Fi and cellular leads inside compact equipment, on camera boards and on detachable earphone cables.

6 MIN

INDUSTRIAL IOT · CONTROL

What Is an IoT Controller?

An IoT controller is a networked device that reads sensors, runs control logic and switches outputs on site, while sending data to and taking commands from a remote server or cloud platform. It combines the job of a small controller with IoT connectivity such as MQTT, Modbus TCP, cellular or LoRaWAN.

6 MIN

NETWORKING · ETHERNET

What Is a NIC (Network Interface Card)?

A NIC (network interface card, or network interface controller) is the hardware that connects a computer to a network. It converts data from the processor into Ethernet or Wi-Fi signals and back, carries the computer’s MAC address, and is either built onto the motherboard or added as a PCIe, M.2 or USB card.

6 MIN

NETWORKING · PROTOCOLS

What Is TCP/IP?

TCP/IP is the suite of protocols the internet and almost every modern network use to move data. It is named after its two main protocols: the Internet Protocol (IP), which addresses and routes packets, and the Transmission Control Protocol (TCP), which delivers data reliably and in order. The TCP/IP model groups the suite into four layers.

7 MIN

NETWORKING · TOPOLOGY

What Is Ring Topology?

Ring topology is a network layout in which each device connects to exactly two neighbours, so the links form a closed loop. Data travels around the ring from node to node. Modern industrial Ethernet rings keep one link blocked and open it when another link fails, typically restoring traffic in under 50 ms with ITU-T G.8032 ERPS.

8 MIN

NETWORKING · TRAFFIC MANAGEMENT

What Is QoS?

QoS (quality of service) is a set of network techniques that give some traffic priority over the rest. Switches and routers classify packets, mark them with a priority such as an IEEE 802.1p or DSCP value, and serve the higher-priority queues first. That keeps delay, jitter and packet loss low for voice, video and control traffic when links are busy.

6 MIN

NETWORKING · FUNDAMENTALS

What Is Packet Switching?

Packet switching is a way of sending data in which a message is split into small blocks called packets, each carrying its own address header. Switches and routers forward each packet independently towards its destination, sharing links with other traffic, and the receiver puts the packets back in order. Ethernet, IP and the internet all use packet switching.

6 MIN

NETWORKING · TOPOLOGY

What Is Bus Topology?

Bus topology is a network layout in which every device connects to one shared cable, the bus or backbone, with a terminating resistor at each end. Every device sees every message and only one can transmit at a time. Bus Ethernet over coax is obsolete, but fieldbuses such as CAN and RS-485 still use a bus.

6 MIN

NETWORKING · TOPOLOGY

What Is Network Topology?

Network topology is the arrangement of the devices and links in a network: how they are cabled (physical topology) and how data flows between them (logical topology). The main types are bus, ring, star, mesh, tree and hybrid. Most wired networks today are stars or extended stars built around Ethernet switches.

7 MIN

NETWORKING · HPC AND AI CLUSTERS

What Is InfiniBand?

InfiniBand is a high-speed, low-latency network for linking servers, GPUs and storage in supercomputers and AI clusters. Defined by the InfiniBand Trade Association, it is a lossless switched fabric with RDMA built in, so data moves directly between the memory of two machines. Current ports run at 400 and 800 Gb/s.

6 MIN

NETWORKING · WI-FI

What Is a Wireless Access Point?

A wireless access point (WAP) is a device that connects Wi-Fi clients to a wired Ethernet network. It bridges IEEE 802.11 radio traffic onto the LAN, usually through one Ethernet cable that also powers it with PoE. Unlike a router, it does not route between networks or hand out addresses; it extends an existing network wirelessly.

8 MIN

NETWORKING · ETHERNET

Network Hub vs Switch: What Is the Difference?

A network hub repeats every incoming frame out of all its other ports, so connected devices share one half-duplex link and its bandwidth. A switch learns which device sits on which port and forwards each frame only to its destination, giving every port full-duplex bandwidth. Hubs are obsolete, and switches have replaced them.

6 MIN

NETWORKING · FIBRE

Single-Mode vs Multimode Fibre: What Is the Difference?

Single-mode fibre has a narrow core of about 9 microns that carries one path of laser light, so it reaches tens of kilometres. Multimode fibre has a wider 50 or 62.5 micron core that carries many light paths, which limits it to a few hundred metres at high speeds but allows lower-cost optics. The SFP transceiver must match the fibre.

5 MIN

NETWORKING · POWER

What Is a PoE Injector?

A PoE injector is a small device that adds power to an Ethernet cable from a non-PoE switch or router. It sits between the network port and the powered device, taking data in on one port and sending data plus power out on the other, so a single camera or access point can run without a PoE switch.

5 MIN

NETWORKING · SWITCHES

What Is a PoE Switch?

A PoE switch is a network switch whose ports supply DC power as well as data over Ethernet cable. It connects devices such as IP cameras, access points and sensors and powers them at the same time, so each device runs from one cable without its own power supply or injector. It shares a fixed power budget across its ports.

6 MIN

NETWORKING · POWER

What Is PoE?

PoE, or Power over Ethernet, sends electrical power and network data down the same Ethernet cable. A powered port on a switch, injector or computer supplies DC power, at around 48 V, to a device such as an IP camera, access point or sensor, so that device needs no separate power supply or mains socket where it is mounted.

6 MIN

NETWORKING · SWITCHING

What Is an Ethernet Switch?

An Ethernet switch is a networking device that connects computers, cameras, controllers and other equipment on a local network. It learns the address of each connected device and forwards every frame only to the port it is meant for, so many devices can communicate at full speed at the same time.

5 MIN

NETWORKING · FIBRE

What Is SFP?

SFP stands for small form-factor pluggable: a compact, hot-swappable transceiver that plugs into a port on a switch, router or computer. The module sets the connection type, so the same port can take multimode fibre, single-mode fibre or copper RJ45. Standard SFP carries up to 1 Gbit/s, and the same-sized SFP+ carries 10 Gbit/s.

8 MIN

NETWORKS · SPEED

What Is Multi-Gig Internet?

Multi-gig internet is broadband faster than 1 Gbps, typically sold in 2, 5, 8 or 10 Gbps tiers over full fibre. To use or measure it, the router, switch and computer need ports faster than Gigabit Ethernet, such as 2.5GbE, 5GbE or 10GbE, because a 1GbE port tops out at around 940 Mbps of real throughput.

6 MIN

OPERATIONS · REMOTE MANAGEMENT

What Is a Truck Roll?

A truck roll is sending a technician in a vehicle to a site to install, check or fix equipment. The term is common in telecoms, utilities and field service, where each visit costs labour, fuel and time. Reducing truck rolls, through remote monitoring and management, is one of the main ways operators cut costs.

5 MIN

NETWORKS · COMPARISON

GPON vs XGS-PON: What Is the Difference?

GPON and XGS-PON are passive optical network standards that share one fibre between many premises. GPON delivers about 2.5 Gbps down and 1.25 Gbps up, shared across the users on that fibre. XGS-PON delivers 10 Gbps in both directions, which makes multi-gigabit and symmetrical tiers practical. Both can run on the same fibre.

6 MIN

NETWORKS · BASICS

What Is FTTP?

FTTP (fibre to the premises) is broadband that runs on optical fibre all the way into a home or business, with no copper in the final connection. It is often called full fibre, and FTTH (fibre to the home) means the same for homes. With no copper bottleneck, it supports gigabit and multi-gigabit speeds, often symmetrical.

6 MIN

MARINE · CONNECTIVITY

How Do Superyachts Get Internet at Sea?

Superyachts combine cellular and satellite connections. Near the coast and in port, 4G and 5G through high-gain marine antennas give fast internet, and bonding several SIMs keeps it reliable. Further offshore, satellite services take over, increasingly low Earth orbit (LEO) systems, with the onboard system switching between links to keep guests and crew connected.

5 MIN

CONNECTIVITY · COMPARISON

Cellular Bonding vs Load Balancing: What Is the Difference?

A load balancing router spreads separate sessions across several connections, but each session, such as a video call, still runs over just one of them. Bonding splits every session across all the connections and reassembles it at a server, so a single stream gets the combined bandwidth and survives one link dropping. Load balancing needs no server; bonding does.

5 MIN

CONNECTIVITY · HARDWARE

What Is a Multi-SIM Router?

A multi-SIM router is a cellular router with two or more SIM card slots. In its simplest form, one modem switches to a backup SIM when the first fails. Routers with a modem per SIM can use every connection at once, for load balancing or bonding, which is what high-bandwidth, always-on applications need.

7 MIN

CONNECTIVITY · BASICS

What Is Cellular Bonding?

Cellular bonding combines several mobile connections, usually from different SIM cards and networks, into one faster and more reliable link. Traffic is split across all the connections and put back together by a bonding server, so even a single video call or upload uses the combined bandwidth and keeps going if one connection weakens or drops.

5 MIN

IIOT · CONNECTIVITY

What Is an IIoT Gateway?

An IIoT (Industrial Internet of Things) gateway is a rugged edge computer that connects industrial equipment, such as PLCs, sensors, meters and machines, to a network or the cloud. It collects their data, translates between industrial and IT protocols, processes and secures it at the edge, and forwards the results.

6 MIN

NETWORKING · SWITCHING

What Is a Managed Switch?

A managed switch is an Ethernet switch you can configure, through a web interface, command line or SNMP, to set up VLANs, quality of service, redundancy and monitoring. An unmanaged switch is plug-and-play with no settings at all. Managed switches suit networks that are segmented, critical or monitored remotely.

8 MIN

NETWORKING · SWITCHING

Layer 3 Switch vs Router: What Is the Difference?

Both a Layer 3 switch and a router forward IP traffic between networks. A Layer 3 switch routes in hardware at close to wire speed across many ports, for traffic inside a site. A router connects a site to outside networks, with WAN interfaces, NAT, firewalling and VPNs, at lower throughput and with fewer ports.

6 MIN

NETWORKING · SWITCHING

What Is a VLAN?

A VLAN (virtual LAN) is a logical segment of a network created in a managed switch. Using IEEE 802.1Q tags, it separates traffic into independent broadcast domains over the same physical wiring, so devices behave as if they are on separate networks.

7 MIN

NETWORKING · POWER

Can a Computer Be Powered by PoE?

Yes. A PoE powered computer takes its power as a powered device (PD) from the same Ethernet cable that carries its data, so it needs no mains socket or local power supply. Low-power computers, gateways and thin clients run from PoE+ (802.3at); larger systems need PoE++ (802.3bt) at up to about 71 W at the device.

5 MIN

NETWORKING · POWER

PoE PD vs PSE: What Is the Difference?

In a PoE link the PSE (power sourcing equipment) supplies the power and the PD (powered device) draws it. A PoE switch, injector or PoE computer acting as a source is the PSE; a camera, phone, access point or PoE-powered display is the PD. The IEEE 802.3 standards define how the two detect, classify and power each other.

6 MIN

NETWORKING · POWER

PoE Mode A vs Mode B: What Is the Difference?

PoE Mode A carries power on the data pairs, pins 1, 2, 3 and 6. Mode B uses the other two pairs, pins 4, 5, 7 and 8. The power source chooses the mode, and every IEEE-compliant powered device must accept either. 802.3bt (PoE++) can use all four pairs at once for higher power.

6 MIN

NETWORKING · POWER

How Much Power Does PoE Deliver?

PoE delivers up to about 15 W per port (802.3af), PoE+ up to about 30 W (802.3at), and PoE++ up to 60 W or 90 W (802.3bt), all at around 48 V DC (44 to 57 V). Some power is lost in the cable, so the device receives a little less than the source supplies.

6 MIN

NETWORKING · POWER

PoE vs PoE+ vs PoE++: The 802.3af, 802.3at and 802.3bt Standards

PoE, PoE+ and PoE++ are the three generations of IEEE Power over Ethernet. PoE (802.3af) supplies about 15 W per port, PoE+ (802.3at) about 30 W, and PoE++ (802.3bt) 60 W (Type 3) or 90 W (Type 4). PoE and PoE+ use two of the four cable pairs; PoE++ can use all four.

6 MIN

NETWORKING · POWER

Active vs Passive PoE: What Is the Difference?

Active PoE follows the IEEE 802.3af, at and bt standards: the source checks for a PoE device and agrees a power class before applying around 48 V DC. Passive PoE is non-standard: it puts a fixed voltage, often 24 V or 48 V DC, on the cable with no handshake, so it can damage equipment not built for it.

6 MIN

NETWORKING · EDGE AI

What is 10GbE networking?

10GbE (10 Gigabit Ethernet) is a networking standard that carries data at 10 gigabits per second, four times faster than 2.5GbE. Defined in the IEEE 802.3 family, it runs over SFP+ fibre or copper and over Cat6A twisted pair, and is increasingly the baseline for edge AI systems handling high-resolution video and multi-sensor data.

5 MIN

NETWORKING · EDGE AI

What is RDMA and why does it matter for edge AI?

RDMA (remote direct memory access) lets one computer read from or write to another computer’s memory through the network card, without passing the data through either CPU or operating system. It cuts latency and frees processor time, which matters for AI clusters and multi-node edge AI. It runs over InfiniBand, or over Ethernet as RoCEv2 or iWARP.

7 MIN

NETWORKING · EDGE AI

What is RoCEv2?

RoCEv2 (RDMA over Converged Ethernet, version 2) is a networking standard that carries RDMA inside UDP/IP packets, so low-latency, low-CPU data transfer can run and be routed over standard Ethernet. It needs RDMA-capable network cards at each end and switches set up to keep packet loss low, usually with PFC and ECN.

5 MIN

NETWORKING · EDGE AI

Is 2.5GbE fast enough for edge AI?

For many edge AI systems, yes. 2.5GbE carries about 2.35 Gbit/s of real traffic over existing Cat5e cable, enough for single-camera inference, compressed multi-camera video and gateway aggregation. It usually falls short for uncompressed machine-vision cameras, multi-sensor fusion and multi-node inference clusters, where 10GbE with RDMA has become the practical baseline.

5 MIN

NETWORKING · EDGE AI

When should you upgrade from 2.5GbE to 10GbE?

Upgrade from 2.5GbE to 10GbE when a workload needs more than about 2 Gb/s of sustained traffic per link, such as several uncompressed camera streams, multi-sensor fusion, multi-node inference or latency-sensitive control. The best time is usually the next platform refresh, specifying RDMA-capable network cards from the start.

6 MIN

NETWORKING · COMPARISON

SFP+ vs RJ45 for 10GbE — what’s the difference?

SFP+ and RJ45 are the two ports used for 10GbE. SFP+ is a cage that takes a plug-in fibre transceiver or a direct-attach copper cable, so one port can reach hundreds of metres or more. RJ45 (10GBASE-T) runs over Cat 6a twisted pair to 100 m and reuses existing copper cabling.

6 MIN

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