Microsoft published an updated version of the Lync protocol workload for all type of conversations: Presence, IM, AV, Webconferencing, Application Sharing and Enterprise Voice.
It looks complex, but it’s a great poster to have if your main job role is deployment and support. It helps you to see all possible elements envolved in a communication while deploying and troubleshooting.
It also has includes the CMS replication workflow, DNS records envolved and Certificates.
If you want download an high definition pdf file or even the visio version, you can get from the Microsoft Download Center here.