Update call-flows.md

Author: fizampou

articles/communication-services/concepts/call-flows.md

@@ -76,7 +76,9 @@ Signaling flows through the signaling controller. Media flows through the Media
 
 :::image type="content" source="./media/call-flows/teams-communication-services-meeting.png" alt-text="Diagram showing Communication Services SDK and Teams Client in a scheduled Teams meeting.":::
 
+### Case 6: Early media
 
+If there is early media flow, the SBC must latch to the first endpoint that starts streaming media; media flow can start before candidates are nominated. The SBC should have support for sending DTMF during this phase to enable IVR/voicemail scenarios. The SBC should use the highest priority path on which it has received checks if nominations have not completed.
 
 ## Next steps