1.3.5.5 Consuming Charge

If the responder is sending a Flat frame (which it does when failing an acknowledged Emit request or responding to an acknowledged Charge request), the amount of charge consumed from the Current Transmit Credit (CTC) is equivalent to the charge required for the outgoing Flat frame.

However, if the responder has accepted an Emit request, acknowledged or unacknowledged, the responder clears the CTC of all charge, including any charge above and beyond that required for the Emit frame. This forces the mapper to rebuild charge on the responder if any future Emit frames are to be sent.

As noted in section 3.2.4.3, unacknowledged Charge frames elicit no response and consume no charge.