HWTACACS is compatible with TACACS+ to some degree. HWTACACS and the TACACS+ protocols of other vendors support authentication, authorization, and accounting. HWTACACS and TACACS+ have identical processes and implementation mechanisms for authentication. That is, they are compatible with each other at the protocol layer. For example, a device running HWTACACS can communicate with a Cisco server (such as ACS). However, HWTACACS may not be compatible with Cisco extended attributes because different vendors define different fields and meanings for extended attributes.