IP and Non IP AT+NCDP confusion

NB-IoT
1

The example code in the link below shows an NB-IoT connection to a Vodafone and T-Mobile network.

http://support.sodaq.com/sodaq-one/at/

The AT+NCDP is only used on the T-Mobile network because it has an IoT platform (OceanConnect now replaced by Nokia Impact?).

The example has the comment:
“The Vodafone network doesn’t use the Neul messaging protocol so there is no need for the AT+NCDP command”.

As far as I understand “AT+NCDP” is required to establish a connection over which non IP messages can be sent from the Node to the IoT platform.

AT+NMGS is used to send the actual Non IP messages.

Questions.

  1. How does a modem on a Vodafone network send non IP messages?
  2. Can “AT+NCDP” connect to ‘any’ server on the network - if so, who provides the required IPsec tunnel?
  3. “AT+NCDP” has a port parameter defaulted to 5683 which is CoAP. Are any other ports/protocols supported?

Many thnaks,
Phil