-calling <tt class="docutils literal"><span class="pre">getPayload()</span></tt> the optional <tt class="docutils literal"><span class="pre">len</span></tt> argument is for also
-obtaining the size of the data region. A provider of a Packet
-interface MUST check if <tt class="docutils literal"><span class="pre">len</span></tt> is NULL and ignore it if it is. A
-component can also obtain the size of the data region with a call to
-<tt class="docutils literal"><span class="pre">payloadLength</span></tt>.</p>
-<p>A component can set the payload length with
-<tt class="docutils literal"><span class="pre">setPayLoadLength.</span></tt> As Send interfaces always include a length
-parameter in their send call, this command is not required for
-sending, and so is never called in common use cases. Instead,
-it is a way for queues and other packet buffering components
-to store the full state of a packet without requiring additional
-memory allocation.</p>
+calling <tt class="docutils literal"><span class="pre">getPayload()</span></tt>. A call to this command includes the length
+the caller requires. The command <tt class="docutils literal"><span class="pre">maxPayloadLength</span></tt> returns the maximum
+length the payload can be: if the <tt class="docutils literal"><span class="pre">len</span></tt> parameter to <tt class="docutils literal"><span class="pre">getPayload</span></tt>
+is greater than the value <tt class="docutils literal"><span class="pre">maxPayloadLength``would</span> <span class="pre">return,</span>
+<span class="pre">``getPayload</span></tt> MUST return NULL.</p>
+<p>A component can set the payload length with <tt class="docutils literal"><span class="pre">setPayLoadLength.</span></tt> A
+component can obtain the size of the data region of packet in use with
+a call to <tt class="docutils literal"><span class="pre">payloadLength</span></tt>. As Send interfaces always include a
+length parameter in their send call, <tt class="docutils literal"><span class="pre">setPayLoadLength</span></tt> is not
+required for sending, and so is never called in common use
+cases. Instead, it is a way for queues and other packet buffering
+components to store the full state of a packet without requiring
+additional memory allocation.</p>