Code,Description,Reference
0.00,Indicates an Empty message.,"[RFC7252, section 4.1]"
0.01-0.31,Indicates a request.  Values in this range are assigned by the [CoAP Method Codes] sub-registry.,"[RFC7252, section 12.1.1]"
1.00-1.31,Reserved,[RFC7252]
2.00-5.31,Indicates a response.  Values in this range are assigned by the [CoAP Response Codes] sub-registry.,"[RFC7252, section 12.1.2]"
6.00-7.31,Reserved,[RFC7252]