Redis is used to synchronize data between traffic switch instances. It stores information about used resources (e.g gateways capacity limits) to provide correct limitation among all nodes for distributed installations.
# apt update && apt install redis-server
to your /etc/redis/redis.conf to enable notifications. This configuration required for incoming registrations functionality.
Try to enter redis console from traffic switch host (redis installed at the same host with traffic switch in this example):
# redis-cli 127.0.0.1:6379> ping PONG 127.0.0.1:6379> quit