A Packet Multiplexer (PMUX) is a mechanism by which a packet stream is filtered in order to split traffic for capture to disk or for decoding to make analytics possible.
SmartNIC hardware, firmware, and software capture, buffer, filter, and route packets into packet streams. PMUXs then read packets from the streams. Usually there is one PMUX for each packet stream; however multiple PMUXs can share a packet stream for scalability. The packets received at a SmartNIC capture port can contain traffic from a tap, Mirror Port, or Packet Broker, and may contain a blend of packets from multiple applications and servers at multiple points in the network.