Transport protocol drop-down box selects which communications protocol- TCP/IP or UDP/IP will be used by the VSP for data communications with the DS.
For the data connection with the DS to work the same transport protocol must be selected on the DS side- see the Transport Protocol (TP) setting .
Unless you have a specific reason why the UDP should be used (very rare!) we recommend you to stick to the TCP/IP. The TCP/IP is a "reliable delivery" protocol that makes sure that no data is lost "in transit" between the VSP and the DS. The UDP, on the contrary, does not guarantee data delivery.
Some considerations and additional info on the TCP and UDP implementation in the VSP can be found in the next topic .