A network TAP (Test Access Point) provides complete visibility into network traffic by creating an exact copy of data flowing through your network and sending it to monitoring and security tools. Unlike SPAN ports that drop packets during high traffic, network TAPs capture 100% of network traffic, including errors and malformed packets, without introducing latency or impacting network performance.
Network TAPs sit between two network devices and passively monitor traffic passing through the connection. When data flows between these devices, the TAP creates a duplicate copy and sends it to your monitoring tools while the original traffic continues uninterrupted to its destination.
Installing a network TAP involves physically placing the device inline on the network link you want to monitor. The TAP has separate ports for the network connection (which maintains your live traffic flow) and monitoring ports (which deliver copied traffic to your security and analysis tools). This architecture ensures your production network remains protected even if monitoring tools fail or lose power.
Network TAPs deliver several critical capabilities that make them essential for network visibility:
Different TAP technologies serve specific network environments and requirements.
Active Ethernet TAPs monitor copper network connections and include electronic components that regenerate signals. These TAPs work on 10/100/1000Base-T networks and often include advanced features like aggregation, filtering, and load balancing.
The SmartNA and SmartNA-XL systems combine active TAP functionality with packet broker capabilities in modular 1RU chassis designs. They support speeds from 1Gbps to 40Gbps and include hot-swappable modules that let you reconfigure without taking the system offline.
Passive fiber TAPs monitor optical fiber connections using beam splitters or fiber couplers to divide the light signal. Because they contain no active electronics, passive TAPs require zero power and cannot be hacked or detected on the network.
These TAPs use mirrors to split the optical light budget according to your requirements. Common split ratios include 50:50, 60:40, and 70:30, with a portion of the light budget maintaining your live network and the remainder sending copied data to monitoring tools. Network Critical offers passive fiber TAPs for various speeds:
Bypass TAPs protect network continuity when inline security appliances fail. These intelligent TAPs monitor the health of inline tools using heartbeat technology and automatically redirect traffic around failed devices in real-time.
When bypass TAPs detect that an inline security appliance has stopped responding, they instantly create an alternate path that keeps your network operational. This prevents security tool failures from causing network outages while allowing you to service or replace tools without scheduling downtime.
Network TAPs provide significant advantages compared to switch SPAN (switched port analyzer) ports, which is why 90% of high-compliance companies prefer TAPs for network monitoring.
SPAN ports randomly drop packets during high network utilization, when handling certain frame types, or when the switch CPU becomes busy. These dropped packets create blind spots that attackers can exploit and make forensic analysis incomplete.
Network TAPs capture 100% of packets with zero loss because they operate independently of switch processing and don't compete with switching functions for resources.
SPAN ports consume switch resources and can degrade network performance, particularly when monitoring high-speed links or configuring multiple SPAN sessions. The additional traffic generated by SPAN mirroring doubles internal switch traffic and can cause congestion.
TAPs operate completely outside the data path and introduce zero latency because they simply copy packets using optical beam splitters or passive electronics. Your production network performance remains unchanged regardless of how many monitoring tools you connect.
Switches discard malformed packets, physical layer errors, and certain protocol violations before they reach SPAN ports. These "error" packets often contain critical security evidence or network troubleshooting information.
Network TAPs capture everything traversing the wire, including errors, because they operate at the physical layer before any packet processing occurs.
Organizations deploy network TAPs across multiple security and operational scenarios.
Security teams use TAPs to feed traffic to intrusion detection systems, security information and event management platforms, and threat hunting tools. The complete packet visibility TAPs provide ensures security tools can detect sophisticated attacks that might hide in the packets SPAN ports drop.
Financial services, healthcare, and government organizations with strict compliance requirements rely on TAPs because regulations often mandate complete traffic capture and monitoring. The legally defensible visibility TAPs provide helps organizations demonstrate compliance during audits.
Network engineers connect protocol analyzers and performance monitoring tools to TAP outputs to diagnose connectivity issues, analyze application behavior, and measure network performance. Because TAPs capture errors and malformed packets, they provide the complete picture engineers need for effective troubleshooting.
Security incident response teams use TAPs to feed long-term packet capture systems that record all network traffic for forensic analysis. When security incidents occur, investigators can analyze complete pcap files without gaps from dropped packets.
Application performance management tools connected to TAPs gain visibility into actual user experience by monitoring real application traffic. This visibility helps IT teams identify whether performance issues originate from the network, servers, or applications.
Modern network TAPs include intelligent features beyond basic packet copying.
Advanced TAPs like the SmartNA-PortPlus can aggregate traffic from multiple network links and present it as a single feed to monitoring tools. This aggregation maximizes tool efficiency by allowing one expensive security appliance to monitor traffic from multiple links rather than requiring dedicated tools for each link.
Network packet brokers with integrated TAP functionality can filter traffic based on Layer 2–4 criteria including IP addresses, protocols, ports, and VLAN tags. This filtering reduces the volume of data monitoring tools must process, extending their effective capacity and improving performance.
The SmartNA-XL includes PacketPro™ advanced packet manipulation that can slice packets to remove payload data, strip headers, or mask sensitive information before forwarding to tools. This data minimization protects privacy while maintaining visibility into connection metadata.
Session-aware load balancing distributes traffic across multiple monitoring tools while maintaining complete session flows. This capability lets you deploy multiple lower-cost tools instead of single expensive high-capacity systems, and ensures tools receive manageable traffic volumes.
Drag-n-Vu is Network Critical's management interface that eliminates the complexity typically associated with configuring network monitoring infrastructure. The sophisticated computational engine with intuitive graphical interface enables fast, error-free configuration through drag-and-drop operations.
Creating filters and mapping traffic to monitoring tools becomes as simple as dragging the cursor over graphical port representations and clicking. The system performs complex rule-generation algorithms in the background, eliminating the need for specialist engineering knowledge for routine configuration changes.
Selecting appropriate TAP technology depends on your network infrastructure, speed requirements, and monitoring goals.
Your TAP must match your network's physical layer characteristics. Ethernet TAPs work on copper networks from 10/100/1000Base-T, while passive fiber TAPs serve optical networks from 1Gbps to 100Gbps.
For the highest-speed networks reaching 400Gbps, the SmartNA-PortPlus HyperCore provides 32 QSFP-DD interfaces with 25.6 Tbps non-blocking architecture in a single 1RU chassis.
Consider where you need visibility and how many links require monitoring. The modular SmartNA system provides flexible port configurations for distributed deployments, while high-density solutions like the SmartNA-PortPlus traffic aggregator scale from 48 ports to 192 ports in compact rack space.
Evaluate how many monitoring and security tools need traffic feeds and whether they require full packets or filtered subsets. Hybrid TAP and packet broker solutions combine packet capture with traffic optimization, letting you connect multiple tools efficiently while maximizing their performance.
The visibility challenges discussed throughout this guide require purpose-built infrastructure designed specifically to overcome the limitations of SPAN ports and legacy monitoring approaches. Network Critical has provided network visibility solutions to enterprises worldwide since 1997, helping organizations achieve comprehensive traffic monitoring without compromising network performance.
Our network TAPs deliver guaranteed packet capture across speeds from 1Gbps to 400Gbps, supporting both passive fiber deployments that require zero power and active Ethernet solutions with advanced aggregation capabilities. The SmartNA family of modular platforms combines TAP and packet broker functionality in compact 1RU chassis, enabling you to deploy complete visibility infrastructure without dedicating entire racks to monitoring equipment.
Whether you're addressing monitoring blind spots, extending visibility into high-speed networks, or building visibility infrastructure for data center environments, our team can help you design an architecture that delivers complete network coverage while maximizing your security and monitoring tool investments.