Network Taps


network tap is used to intercept the signals passing over a cable and send them to a packet or protocol analyzer.

Types of Taps

  • Taps are either powered or unpowered:
    • passive test access point (TAP) is a box with ports for incoming and outgoing network cabling and an inductor or optical splitter that physically copies the signal from the cabling to a monitor port.
      • No logic decisions are made,
        • monitor port receives every frame
          • corrupt or malformed or not
        • copying is unaffected by load
    • An active TAP is a powered device that performs signal regeneration
      • use case for active TAP
        • Gigabit signaling over copper wire is too complex for a passive tap to monitor
        • some types of fiber links may be adversely affected by optical splitting
      • Because it performs an active function,
        • TAP becomes a point of failure for the links during power loss

Port Mirroring/SPAN

Network sniffing can also be facilitated using a mirror port.