Napatech card
A specialized network card which does part of the packet filtering and processing in dedicated hardware, as opposed to doing filtering and processing on the CPU.
Probe
A machine which filters and processes network traffic. It doesn't calculate the statistics.
RTP
The voice part of the network traffic, as opposed to the signaling (meta) part.
VLAN
VLAN (Virtual Local Area Network) is a technique to separate a network into distinct, isolated broadcast domains. See
https://en.wikipedia.org/wiki/Virtual_LAN