Network monitor and method

A network monitor that taps data from a network link between two network devices, the network monitor comprising:

• first and second interfaces that allow the network monitor to be connected in-line in a network link between two network devices and to receive serial data therefrom and to transmit serial data thereto, each interface providing for serial-to-parallel conversion of data such that serial data received from a said network link at the interface is output as parallel data, and each interface providing for parallel-to-serial conversion of data such that parallel data received at the interface is output as serial data for transmission to a said network link;
• and,
• first and second programmable logic devices,
• the first programmable logic device being arranged to receive parallel data output by the first interface and to process said data for network analysis purposes, the second programmable logic device being arranged to receive parallel data output by the second interface and to process said data for network analysis purposes, each programmable logic device being controllable so as to selectively pass a copy of the received parallel data to the other programmable logic device so that the network monitor can operate in in-line mode and not to pass a copy of the received parallel data to the other programmable logic device so that the network monitor can operate in end station mode,
• the second programmable logic device being arranged to pass the copy of the parallel data received from the first programmable logic device to the second interface for parallel-to-serial conversion and for transmission of the serial data back to a said network link when the network monitor is operating in in-line mode,
• the first programmable logic device being arranged to pass the copy of the parallel data received from the second programmable logic device to the first interface for parallel-to-serial conversion and for transmission of the serial data back to a said network link when the network monitor is operating in in-line mode.