This part of pushjet manages the communication between clients that are listening to pushjet and the server. It uses ZeroMQ for the messaging which allows the server to be scaled at ease. The method for sending out messages is called pub/sub. It makes sure that only the messages that matter are processed by the right connections.
make
sudo make install
cp init.d/pushjet-broker.sh /etc/init.d/pushjet-broker
/etc/init.d/pushjet-broker start