Even if you’ve already realized the inferiority of SPAN ports and started moving to network TAPs, you still have to make sure your network design is set up for visibility into every bit, byte and packet® of traffic.
However, the increasing complexity of the security stack and necessary network monitoring solutions are making it harder than ever to maintain an efficient network design.
As more in-line appliances and out-of-band monitoring tools are added to the network, architects must pay close attention to the amount of traffic they’re sending to each port.
Standard breakout mode may have worked in all use cases in the past, but copying 100% of traffic to all ports is no longer an option in many cases. Let’s dive into a practical example of tapping 1G in-line and out-of-band solutions without oversubscribing your ports.
The new 1G Modular Packet Broker System from Garland Technology is designed to support breakout, aggregation, filtering, regeneration/SPAN and bypass modes for total flexibility and scalability. The 2U chassis option can help you manage your in-line and out-of-band solutions without oversubscribing 1G ports.

In this scenario, the eastbound and westbound traffic passes through the modular TAP in breakout mode. A complete copy of the traffic is aggregated and sent to corresponding appliances (in this case, the web application firewall.
However, because the monitoring ports can only support 1G, the TAPs must also filter out packets that aren’t necessary for the web application firewall to scrub. Using the remote management interface of the 1G Modular Packet Broker System, you can easily set the parameters for filtering and ensure in-line and out-of-band solutions see every bit, byte and packet® necessary.
Aside from the fact that they can’t ensure 100% packet visibility, one reason SPAN ports are inferior to network TAPs is that the number of ports is limited compared to the number of in-line
and out-of-band solutions you have to connect. As you add more appliances to your network, you need a design that minimizes the number of ports you use.
Port Mapping (or backplane filtering) on the new 1G Modular Packet Broker System means you can aggregate low traffic links and send them to a single in-line or out-of-band solution without oversubscribing ports.
Think of this in terms of your own network where you might have a Palo Alto Next-Generation Firewall and the NextComputing Packet Continuum to send traffic to. With the 1G Modular Packet Broker System and port mapping, you can take multiple 1G links and filter out any unnecessary data before sending copies to both the monitoring device and in-line security appliance.
This is just one use case for the new 1G Modular Packet Broker System. With space for up to 12 TAP modules - there are so many ways you can configure the chassis for your specific needs. All modules are hot swappable for onsite changes coupled with remote management to easily click a mouse to switch from bypass to aggregation or breakout modes.
One of the greatest benefits of the new 1G Modular Packet Broker System is the flexibility it gives you to scale your network alongside growing security and monitoring stacks. But this also means you need a strong network design to ensure appliances are seeing every bit, byte and packet® without oversubscription.
If you want to learn more about the ins and outs of network connectivity, download our latest white paper, Network Connectivity: A Go-To Guide.
If the inline security tool goes off-line, the TAP will bypass the tool and automatically keep the link flowing. The Bypass TAP does this by sending heartbeat packets to the inline security tool. As long as the inline security tool is on-line, the heartbeat packets will be returned to the TAP, and the link traffic will continue to flow through the inline security tool.
If the heartbeat packets are not returned to the TAP (indicating that the inline security tool has gone off-line), the TAP will automatically 'bypass' the inline security tool and keep the link traffic flowing. The TAP also removes the heartbeat packets before sending the network traffic back onto the critical link.
While the TAP is in bypass mode, it continues to send heartbeat packets out to the inline security tool so that once the tool is back on-line, it will begin returning the heartbeat packets back to the TAP indicating that the tool is ready to go back to work. The TAP will then direct the network traffic back through the inline security tool along with the heartbeat packets placing the tool back inline.
Some of you may have noticed a flaw in the logic behind this solution! You say, “What if the TAP should fail because it is also in-line? Then the link will also fail!” The TAP would now be considered a point of failure. That is a good catch – but in our blog on Bypass vs. Failsafe, I explained that if a TAP were to fail or lose power, it must provide failsafe protection to the link it is attached to. So our network TAP will go into Failsafe mode keeping the link flowing.
Single point of failure: a risk to an IT network if one part of the system brings down a larger part of the entire system.
Heartbeat packet: a soft detection technology that monitors the health of inline appliances. Read the heartbeat packet blog here.
Critical link: the connection between two or more network devices or appliances that if the connection fails then the network is disrupted.