This article speaks to the wiring for Vectra Networks S2 sensors. The S2 sensor can be configured in two distinct ways, which are described below.
Traditional installation: using IN ports only on S2 sensors
The Cognito S2 sensor has two capture ports. They are labelled '1 IN' and '2 IN'.
These two capture ports can be connected to SPAN/port mirroring output interfaces.
By connecting the 1 IN and/or 2 IN ports to mirroring sources, the S2 sensor will receive the correct traffic for the environment.
Non-traditional installation: using IN and OUT ports on S2 sensors
The Cognito S2 sensor also has two output interfaces, labelled '1 OUT' and '2 OUT'.
The nOUT interfaces are offered explicitly - and only - for configurations where the site configuration cannot accommodate the use of SPAN/port mirror interfaces on the switches.
The IN/OUT port pairs behave similarly to an Ethernet cable. When nOUT are used, packets received on the nIN interface are transmitted (blindly) out of the respective nOUT interface and vice versa.
When installed inline (between the switch and a router, for example) the S2 sensor should have the IN ports connected to the switch and the OUT ports connected to the router. The packet forwarding by the S2 sensor allows it to be transparent to the network.
WARNING! Connecting the 1 OUT port back to the switch will cause a packet loop. Packets received on the 1 IN port are sent out of 1 OUT back to the switch, where they are again captured by the mirroring port and sent back to the S1 on the 1 IN interface.
Please only connect OUT to downstream devices which do not introduce packet duplication.