All Cisco Jabber clients register with a central IM and Presence Service node when a user logs into the system. This is Cisco Unified Presence or Cisco Unified Communications Manager IM and Presence Service node in on-premise deployments or Cisco WebEx in cloud-based deployments. This node tracks availability, contact lists, and other aspects of the IM and Presence Service environment.
This IM and Presence Service node tracks all of the registered clients associated with each unique network user. When a new IM session is initiated between two users, the first incoming message is broadcast to all of the registered clients of the receiving user. The IM and Presence Service node then waits for the first response from one of the registered clients. The first client to respond subsequently receives the remainder of the incoming messages until the user starts responded using another registered client. The node then reroutes subsequent messages to this new client.
Adam wishes to initiate an IM conversation with Anita. Anita has previously logged into Cisco Jabber for Windows and Cisco Jabber for Android. Anita has registered two clients with the central IM and Presence Servicenode. Adam initiates the conversation by sending the message, "Hi Anita. Are you free?"
The node identifies that Anita has two registered clients and broadcasts Adam's message to both.
Anita is sitting at her desk and observes Adam's message appearing on both her laptop and phone. She chooses to respond using her laptop and responds with the message, "I have a meeting in a few moments but I can chat briefly right now."
The IM and Presence Service node identifies that Anita has responded using Cisco Jabber for Windows and marks this as the client to route all subsequent messages to in the conversation. When Adam responds with "This will only take a minute," it is routed directly to Cisco Jabber for Windows. If Anita starts responding to Adam using her phone at some point in the conversation, the IM and Presence Service node then routes subsequent messages there instead of to Cisco Jabber for Windows.
