Additional ports can be defined for Openflow channel due to various reasons (redundancy, load balancing). Openflow connection established through additional ports is called auxiliary connection. By defining auxiliary connection, we have multiple connections (Openflow channel) between a single switch and a controller. In order to make OpenFlow communication via the auxiliary port, the main channel connection must first be established. If the main channel connection is off, the auxiliary connections are also cannot used. In case of functionally, there is no difference between main channel connection and auxiliary connection.