Question about channel passing

Dear all,

 

I am working on an execution environment for WS-CDL collaborations. I have,
however, some questions with regards to channel passing in WS-CDL.

For instance with the following sentence (in 4.4 ChannelType): When a
channel instance of this channelType is passed, the passer of the channel
instance MUST relinquish control, for outputting only, of that instance and
passes control to the receiver. What is understood by "for outputting only"?
Does this mean that the passer of the channel instance won't receive any
responses over this channel instance or does this mean that the passer
cannot send any more messages over this channel instance?

Another question is related to channel passing of a channelType with usage
declared to "once". When such a channelType is used in an interaction a new
instance needs to be created, right? But, what is the purpose of passing
such a channel instance to another participant, if he cannot use this
instance anymore?

 

Thanks in advance for your time.

Kind Regards,

Gregory