Overview#Authentication and Authorization for Constrained Environments (ACE) is an IETF Working Group which works to developed protocols for use in Constrained environments, where network nodes are limited in CPU, memory and power.
REST architecture is widely used for such constrained environments.
However it has been observed that Internet protocols can be applied to these constrained environments, often only requiring minor tweaking and profiling. In other cases, new protocols have been defined to address the specific requirements of constrained environments. An example of such a protocol is the Constrained Application Protocol (CoAP).