licy and control and to propagate signals about mesh behavior to other systems for analysis. The policy runtime supports a standard extension mechanism for plugging in other services. In addition, it allows for the extension of its vocabulary to allow policies to be enforced based on new signals that the mesh produces.</p></li><li><p><strong>Portability</strong>. The ecosystem in which Istio will be used varies along many dimensions. Istio must run on any cloud or on-prem environment with minimal effort. Th