<img height="1" width="1" style="display:none;" alt="" src="https://px.ads.linkedin.com/collect/?pid=2975524&amp;fmt=gif">
BLOG

Follow the History and Added Function of the Network TAP

December 6, 2016

The two most common methods to access network data are via a Network TAP or from a SPAN port.

How much do you know about Network TAPs? If you don't use them, maybe you think it's just another failure point or there may be a forwarding delay. If you do use them you probably consider them a must have.

What if I can answer some of those questions you may have in a few quick points?


NETWORK TAPs

Let's refresh - a TAP (Network Test Access Point) transmits the send and receive data streams simultaneously on separate dedicated channels, ensuring all data arrives at the monitoring device in real time.100% of the data, it doesn't get better than that!

Network TAPIn 2000, Garland Technology’s CTO/Co-founder Jerry Dillard developed the bypass TAP to continuously check the health of active, in-line appliances- ensuring traffic flows regardless of the appliances condition. 

The passive network TAP was patented around 2002 as a device allowing a third party to “listen-in” to network activity.

Network TAPs can do a lot of things you may not realize. They can be passive “listen only” devices that sends all data to your monitoring tools. Or they can be active, in-line feeding your security tools, providing you a failsafe. Meaning if a failure occurs with the appliance or the tap, the live network traffic is not affected. Can SPAN do that?

With packet capture, the TAP does not distort or drop packets, regardless of bandwidth including physical layer errors. TAPs do not alter the time relationships of frames, spacing or response times and supports full duplex traffic analysis.

SPAN

SPAN portYes, we've all used the SPAN port. Did you know the SPAN or monitor port was originally a quality assurance test point developed by Cisco on Catalyst switches for mirroring packets to a port for monitoring purposes?

Unlike the TAP, packets can be dropped when ports are oversubscribed and can distort real time communication such as VoIP and video chats, making lawful intercept unacceptable.

Today's network, security and management pros require 100% network uptime while maintaining full network visibility and access. You can't afford to not see every bit, byte and packet®.


Which do you use to feed your tools? Click below and take a look at the new TAP vs SPAN infographic and compare the difference. 

TAP vs SPAN

 

See Everything. Secure Everything.

Contact us now to secure and optimized your network operations

Heartbeats Packets Inside the Bypass TAP

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.

Glossary

  1. 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.

  2. Heartbeat packet: a soft detection technology that monitors the health of inline appliances. Read the heartbeat packet blog here.

  3. Critical link: the connection between two or more network devices or appliances that if the connection fails then the network is disrupted.

NETWORK MANAGEMENT | THE 101 SERIES