3.3.5.1 Receiving Message #1

On receipt of message #1, the host MUST check for the presence of a "FRAGMENTATION" vendor ID payload. If a "FRAGMENTATION" vendor ID payload is present in the message, the host MUST set the Fragmentation supported flag for the corresponding MMSAD entry.

Then, the host MUST construct message #2 (as specified in [RFC2409] section 5) and add the "FRAGMENTATION" vendor ID payload to advertise its fragmentation capability.