As per https://github.com/twitter/cloudhopper-smpp/pull/101
The SMPP spec does not seem to be clear in this regard but we have an instance of an ESME sending an enquire_link PDU and expecting a response while the channel is open but not bound. It seems that this could be valid according to section 2.4 (Operation Matrix) (http://docs.nimta.com/smppv50.pdf) as they can use this to check the channel is valid and available before making a bind request. Changing the behaviour of the UnboundSmppSession class to support this and send a simple response in reply.
As per https://github.com/twitter/cloudhopper-smpp/pull/101 The SMPP spec does not seem to be clear in this regard but we have an instance of an ESME sending an enquire_link PDU and expecting a response while the channel is open but not bound. It seems that this could be valid according to section 2.4 (Operation Matrix) (http://docs.nimta.com/smppv50.pdf) as they can use this to check the channel is valid and available before making a bind request. Changing the behaviour of the UnboundSmppSession class to support this and send a simple response in reply.