Network administrator and cabling teams are the key persons spotting the security breaches in an organization. Two technologies currently used in network monitoring systems: SPAN (switched port analyzer), also known as port mirroring, and TAP (traffic access point). A SPAN port copies traffic from any traffic port to a single unused port. SPAN ports also prohibit bi-directional traffic on that port to protect against back flow of traffic into the network, and direct packets from its switch or router to the test device for analysis. A tap, on the other hand, is a passive component that allows non-intrusive access to data flowing across the network and enables monitoring of network links. A tap uses passive optical splitting to transmit inline traffic to an attached monitoring device without data stream interference. So, they are completely passive and cause no disruption to the live network.
Choosing an option among two that allows you to monitor your network without affecting live applications. A tap enables you to do exactly that. Network monitoring when implemented optimally should allow you to see all network traffic including errors, regardless of packet size, in real time. Taps are truly passive and do not add any additional load onto the live network. A TAP device simply splits the signal instead of replicating it, a portion of that signal can be taken offline, or out of band, to conduct analysis of the I/O traffic without affecting live applications.
A SPAN port is actually configured by a network engineer and it needs to be disabled during a network refresh, if it is not done then it is possible ,that port to be cabled to serve as a network port, creating a “bridging loop,” which will result in network performance issues.
When It comes to cost, A 10G switch port is more expensive than a 1G switch port, whereas a tap port at 1G costs the same as a tap port at 10G or even 40G. For these reasons, optical tapping is becoming a more popular solution for higher data rates.