The Network Tap: Getting To Know The Basics

Networking and security professionals have enough to worry about without struggling against inefficient (or non-existent) access points.

As network design becomes increasingly complex with the addition of new services, the traffic access challenge must be solved to maximize visibility.

That’s why network taps (or, network test access points) are essential tools for any IT team.

What Is a Network Tap?

The value of network taps is often dismissed because they’re seen a simple devices for accessing network traffic. And while that’s a key function of network taps, it’s not the whole story.

More specifically, a network tap creates a copy of network traffic and sends it to various monitoring devices across your infrastructure. While they tap into your traffic for analysis, network taps don’t modify the data stream in any way—even when port mirroring is enabled.

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These devices have two main functions. First, they act as unobtrusive observers, sending complete copies of data packets to connected security and monitoring devices. And second, they act as out-of-band appliances that don’t impact data flow in cases of failure.

On a high level, network taps are meant to maximize your visibility into every data stream. However, there are two main categories of network taps that all use cases fall under—active and passive.

The Role of Active Network Taps

Active network taps are based on active switching configurations for generating copies of data packets. These copies are regenerated without losing signal power. And if the power source to your active network taps fails, you won’t see interrupted traffic flows.

One of the most important use cases for active network taps is to ensure uptime of in-line security appliances on your network. Deploying next-gen firewalls, intrusion prevention systems, data leakage prevention appliances, and DDoS protection won’t help if they interrupt data flows.

Bypass network switches are active tools that provide fail over capabilities for in-line security solutions. If your appliances go down, traffic automatically skips the point of failure to maintain data flow.

At a time when businesses rely so heavily on application availability, active network taps deliver reliability without sacrificing performance.

The Role of Passive Network Taps

Passive network taps are based on optical splitters to ensure the tapped access point and monitoring appliances are always connected. Unlike active network taps, passive tools don’t need their own power supplies.

Passive network taps are best-suited for out-of-band monitoring use cases. These tools will copy all network data between two points and send it to any performance management or monitoring tools necessary.

And, like active network taps, these passive solutions maintain traffic flow even in case of power failures because they’re directly connected to corresponding network ports with splitters.

Network Taps vs. SPAN Ports for Copying Traffic

Before the advent of network taps, networking pros would use SPAN (switched port analyzer) for creating mirrored copies of traffic. Because SPAN ports are so readily available on network switches, they’ve always been accepted mechanisms for accessing detailed packet information and delivering traffic to security/monitoring tools.

However, network complexity has exceeded the capabilities of SPAN. Each switch has a limited number of SPAN ports, so decisions must be made on traffic priority. Then, your choices are limited for setting targets for copied data.

When SPAN resources are exhausted, networking pros face challenges maximizing visibility.

Unlike SPAN ports, network taps see all traffic, all the time. They aren’t dependent on the limitations of switches. Whatever traffic needs to be replicated can be replicated and sent to appropriate in-line and out-of-band monitoring/security solutions.

Choosing the Right Network Taps

The key to getting value out of network tap investments is choosing the right tools for your specific needs. In most cases, there aren’t any one-size-fits-all solutions that will solve every network visibility challenge.

However, if you take the right steps, you can find a cost-effective way maximize network visibility so your security and monitoring investments deliver the greatest returns. Check out this white paper for more information about designing for effective network visibility.

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