https://devzone.nordicsemi.com/f/nordic-q-a/24163/what-does-access-model-and-model-id-refer-to-respectivelyHi, when reading the BLE Mesh example code, I got really bewildered by this function: access_model_add and inside, there is this gem: element_has_model_id I understand mesh &quot;protocol&quot; is concept-heavy, but I&#39;m pretty sure neither notionen-USTelligent Community 13Tue, 08 Aug 2017 11:54:58 GMThttps://devzone.nordicsemi.com/thread/95166?ContentTypeID=1Tue, 08 Aug 2017 11:54:58 GMT137ad170-7792-4731-bb38-c0d22fbe4515:5a4298b5-f97b-4d78-8d74-914b8ebbb7f7Thomas Stenersen<p>Hi Mitch996,</p> <p>There is no &quot;access model&quot;, the function is in the <code>access.c</code> module and thus prefixed with <code>access_*</code>. The function adds a model to the access layer, it is the component/layer that deals handles the element and model structure. Please have a look at the section about the access layer in the <a href="http://infocenter.nordicsemi.com/topic/com.nordic.infocenter.meshsdk.v0.9.1/md_doc_getting_started_basic_concepts.html?cp=4_3_0_3_1">introduction to Bluetooth mesh</a>.</p> <p>The model ID is a unique ID for every defined model. See section &quot;3.7.2 Model identifier&quot; in the Mesh profile specification. Only one instance of a model can be present on any element. The function <code>element_has_model_id()</code> tests that this holds true.</p> <p>Best regards,<br /> Thomas</p><div style="clear:both;"></div>