Operational Technology (OT) networks now sit at the front line of critical infrastructure security. As IT/OT convergence accelerates across energy, manufacturing, oil and gas, and utilities, the risks of inadequate traffic visibility have never been higher. A ransomware attack on a connected Industrial Control System (ICS) can halt production for days, trigger safety incidents, and invite regulatory scrutiny under frameworks like NIS2 and NERC CIP.
Passive network TAPs (Test Access Points) and packet brokers are the hardware foundation of effective OT visibility. They create unfiltered, zero-impact copies of live traffic, feeding security tools with the data they need to detect threats, validate segmentation, and meet compliance obligations. Unlike Switch Port Analyzer (SPAN) ports, purpose-built TAPs guarantee 100% packet capture without risk of dropped frames or network disruption.
This guide compares five verified vendors delivering network visibility solutions for OT environments in 2026.
| Vendor | Key Strength | Max Throughput |
|---|---|---|
|
Hybrid TAP/packet broker, ruggedized options, INVIKTUS zero-trust |
Up to 400G |
|
|
Purpose-built OT TAP, DIN rail, -40°F to 185°F operating range |
Up to 100G |
|
|
Industrial copper TAPs, DIN rail, 20–30 VDC, portable field tools |
Up to 10G |
|
|
21-module OT chassis in 3RU, 48 native RJ45 copper ports |
Up to 10G (copper chassis) |
|
|
Open Visibility Platform, fail-safe active TAPs, modular architecture |
Up to 400G |
SmartNA-XL, SmartNA-PortPlus, and INVIKTUS
Network Critical's OT network monitoring solutions are built around the principle of zero disruption to live industrial processes. The SmartNA-XL combines hybrid TAP and packet broker functionality in a single 1RU chassis, supporting 1G to 40G links across copper, multimode, and single-mode fiber. It features five modular slots accepting passive, active, and bypass TAP modules, so teams can adapt the access layer without replacing the chassis.
For higher-density environments, the SmartNA-PortPlus scales from 48 to 194 ports across 1G/10G/25G/40G/100G speeds. The SmartNA-PortPlus HyperCore extends this to 400G with 32 QSFP-DD interfaces, covering the most demanding converged OT/IT data center environments. All products are managed through Drag-n-Vu, Network Critical's patented graphical interface, which eliminates manual rule configuration and supports automated filtering via REST API.
For OT environments requiring zero-trust access control at the network perimeter, INVIKTUS adds a hardware-based security layer. It carries no IP or MAC address, making it invisible to threat actors, and enforces strict policy-based access so only validated traffic reaches critical systems. The combination of passive visibility and active zero-trust enforcement addresses both monitoring and protection requirements under a single vendor.
Network Critical's network TAPs use fail-safe passive fiber designs that require no power, meaning industrial links stay operational even during complete power loss. Ruggedized enclosures protect against dust, moisture, and vibration, covering deployments in harsh industrial settings.
Proven Results:
P1GCCB-OT, Military-Grade Industrial TAP, Hardware Data Diode
Garland Technology has built one of the most explicit OT-focused TAP portfolios in the market. Their P1GCCB-OT industrial TAP is engineered for tough environments including manufacturing, transportation, utilities, and oil and gas. It operates across a temperature range of -40°F to 185°F (-40°C to 85°C), snaps onto a standard 35mm DIN rail, and draws wired DC power (9–36 VDC) to prevent outages caused by vibration. It carries no IP address, eliminating any risk of the TAP being used as an attack vector.
The Military-Grade Industrial TAP extends this further, with a durable metal chassis and modular design supporting 10M/100M/1G copper monitoring in the most restrictive physical environments. Garland's Hardware Data Diode enforces unidirectional traffic flow from SPAN ports to monitoring tools, creating a hardware-enforced barrier against reverse data injection into critical OT systems.
Garland's TAPs support speeds from 10M to 100G across copper and fiber configurations, and integrate natively with OT security platforms including Dragos and Darktrace. Their TAP-to-Tool™ program ensures verified compatibility with a wide range of security and monitoring tools. Garland also publishes an extensive library of OT-specific educational resources, including ICS visibility guides for utilities and alignment content for the 2025 SANS State of ICS/OT Security Survey.
C1D-100, ProfiShark 100M, Booster Aggregation TAP
Profitap is a European vendor with a focused industrial Ethernet product line. Their C1D-100 industrial copper TAP features DIN rail mounting, 20–30 VDC powering, and passive access for 10/100 Mbps links. It monitors all seven OSI layers, mirrors packets of all sizes and types, and incorporates a built-in Data Diode to block any injection of data from the monitor ports back into the live network.
The ProfiShark 100M is purpose-built for industrial Ethernet protocols and real-time traffic. It provides fully passive, fail-safe access to 10/100 Mbps links with Power over Ethernet (PoE) passthrough, and captures traffic to USB 3.0 for immediate field analysis. This makes it a practical tool for OT engineers conducting protocol troubleshooting or incident response on the plant floor without deploying permanent infrastructure.
For environments with multiple monitoring points, Profitap's Booster Aggregation TAP consolidates up to four full-duplex links into a single output feed, supporting low-bandwidth OT links and inline or SPAN-based deployments. The Booster's Data Diode function prevents reverse traffic flow, which is a key requirement for ICS network segmentation. Profitap's fiber TAPs are backed by a 10-year warranty, and the company ships most products from stock for next-day delivery.
OptoSlim TAP Series, OT Copper Chassis
Cubro Network Visibility delivers carrier-grade network visibility with a specific solution set for converged OT environments. Their OT-focused copper chassis accommodates up to 21 TAP modules in just 3RU, with 48 native RJ45 ports for 10/100/1000BASE-T networks. This high module density addresses industrial environments where large numbers of legacy copper endpoints must be monitored without rebuilding the physical infrastructure.
The chassis uses fail-safe, hot-swappable architecture, so modules can be replaced or reconfigured without taking the system offline. An integrated 4x 1G/10G SFP+ uplink connects the copper TAP tier to fiber-based monitoring tools, bridging the media gap common in IT/OT converged architectures. Cubro's Drag-n-Vu-style graphical interface supports granular filtering and traffic management, and the platform's OT-specific design accounts for legacy protocols used across SCADA systems and industrial control environments. Cubro has over two decades of experience in network visibility and is a verified Vodafone supplier.
Open Visibility Platform, Network TAPs, Network Packet Brokers
Niagara Networks provides an Open Visibility Platform that combines TAPs, packet brokers, and bypass switches under centralized orchestration. Their active TAP devices include fail-safe circuitry that keeps links operational if the TAP loses power, a critical requirement for OT environments where any link interruption can trigger safety events or production stoppages.
Passive fiber TAPs from Niagara mirror all network traffic without introducing a point of failure. Active TAPs participate in link negotiations and support TAP aggregation for environments requiring consolidated traffic feeds. Niagara's platform supports speeds up to 400G and is compatible with physical and virtual network infrastructures, making it suitable for organizations managing hybrid OT/IT architectures.
The Open Visibility Platform provides centralized visibility management across multiple monitoring points, reducing the operational overhead of managing distributed TAP deployments across large industrial sites. Niagara maintains technology alliance partnerships with major security and monitoring vendors, ensuring verified integration across OT security stacks.
OT environments often run a mix of copper and fiber links, with legacy equipment operating at 10M or 100M speeds alongside modern 1G and 10G infrastructure. Confirm whether your shortlisted TAP supports the physical media types in your environment before evaluating any other criteria. Copper TAPs must be powered, whereas passive fiber TAPs require no power and introduce zero risk of link failure. If you're bridging copper to fiber for tool connectivity, look for solutions with built-in media conversion.
Standard IT equipment is not rated for industrial environments. If your network links run through manufacturing plant floors, substations, refineries, or transportation infrastructure, you need TAPs rated for:
Deploying consumer-grade hardware in these conditions risks false link failures and unreliable packet capture.
In OT environments, the network link must stay operational even if the TAP loses power. Any TAP you deploy should pass live traffic in fail-safe mode the moment it loses power, without any configuration or manual intervention. For passive fiber TAPs, this is inherent to the optical design. For copper TAPs, verify the fail-safe mechanism explicitly. A TAP that takes the link down during a power glitch is not suitable for production OT deployments.
A standalone TAP gives you passive access to a single link. If you need to aggregate traffic from multiple TAP points, filter by protocol or IP range before it reaches security tools, or distribute traffic to more than one monitoring tool, you need packet broker functionality. Organizations with more than a handful of monitoring points typically benefit from a hybrid TAP and packet broker solution, which consolidates the access and distribution layers into a single managed platform. This reduces rack space, simplifies operations, and lowers total cost of ownership.
NIS2, NERC CIP, and IEC 62443 each require demonstrable network monitoring capabilities for covered organizations. Your visibility solution should support audit-ready traffic logging, physical separation of monitoring paths from live traffic, and the ability to prove 100% packet capture at key network segments. If your compliance framework specifies unidirectional data flow for certain network zones, confirm that the TAP includes hardware Data Diode functionality rather than relying on software-enforced restrictions.
Your TAP or packet broker needs to feed traffic to the OT security platforms already in your environment — whether that's Dragos, Claroty, Nozomi Networks, or another monitoring platform. Check for verified integration documentation or technology alliance listings from your shortlisted visibility vendor before committing to hardware.
A network TAP (Test Access Point) is a hardware device that creates a passive, unfiltered copy of live traffic on a network link without affecting the traffic itself. In OT networks, TAPs are preferred over SPAN ports because they guarantee 100% packet capture with no dropped frames, carry no IP or MAC address so they cannot be attacked, and fail-safe in hardware so the network link stays up even if the TAP loses power. These properties are essential in industrial environments where availability and safety take precedence over all other considerations.
A TAP is a dedicated hardware device that passively copies all traffic on a link, including physical errors and malformed frames. A SPAN port is a software-configured switch feature that mirrors selected traffic to a monitoring port. SPAN ports drop packets under load, cannot capture physical-layer errors, and can introduce performance overhead on the switch. In OT environments, SPAN port limitations are a common cause of visibility gaps that leave security tools working with incomplete data.
If you have more than one or two monitoring tools, or more than a handful of TAP points across your OT environment, a packet broker is worth considering. Network packet brokers sit between your TAPs and security tools and handle aggregation, filtering, and distribution — ensuring each tool receives only the traffic it needs. Without a packet broker, monitoring tools can be overwhelmed by irrelevant traffic, which degrades detection accuracy and increases processing load.
For most industrial deployments, look for an operating temperature range of at least -40°C to +85°C, resistance to vibration and electromagnetic interference, support for DIN rail mounting, and DC power input options (typically 24V or 48V). If the TAP is to be installed in an ICS cabinet, a compact form factor and screw-lock connectors also matter. Standard rack-mount IT equipment is not suitable for plant floor or substation deployments without verification of environmental ratings.
A hardware Data Diode enforces strictly unidirectional traffic flow at the physical layer, making it physically impossible for data to travel in the reverse direction. In OT security, this means monitoring traffic can flow from the OT network to security tools, but nothing can be injected back into the OT network through the monitoring path. This is a stronger guarantee than software-enforced controls, which can be misconfigured or bypassed.
Choosing the right network visibility hardware is one of the most consequential decisions in an OT security program. The wrong choice creates blind spots that attackers exploit; the right choice gives your security tools the packet-level data they need to detect threats, validate segmentation, and meet compliance obligations without disrupting production.
Network Critical's combination of passive TAPs, hybrid TAP/packet broker platforms, and the INVIKTUS zero-trust security layer makes it one of the few vendors that addresses both visibility and access control within a single architecture. With proven deployments at BP, Airbus, and HSBC, and a product range covering 10 Mbps to 400G, Network Critical scales to match your OT environment today and as it grows.
To discuss your OT network visibility requirements or request a free network audit, speak to the Network Critical team.