Availability and Instant Messaging Overview
IM and Presence Service allows your users to share their availability status with their contacts.
Point-to-point instant messaging supports real-time conversations between two users at a time. IM and Presence Service exchanges messages directly between users, from the sender to the recipient. Users must be online in their instant message clients to exchange point-to-point instant messages.
Instant messaging capabilities include:
- Instant Message Forking
When a user sends an instant message to a contact who is signed into multiple instant message clients, IM and Presence Service delivers the instant message to each client. IM and Presence Service continues to fork instant messages to each client, until the contact replies. Once the contact replies, IM and Presence Service only delivers instant messages to the client on which the contact replied.
- Offline Instant Messaging
When a user sends an instant message to a contact who is not signed in (offline), IM and Presence Service stores the instant message and delivers it after the offline contact signs back in to their instant message client.
- Broadcast Instant Messaging
Allows a user to send an instant message to multiple contacts at the same time, for example, when a user wants to send a notification to a large group of contacts.
Please note that not all instant message clients support broadcasting.
Maximum Contact List Size
Configure the maximum contact list size for a user; this is the number of contacts the user can add to their contact list. This setting applies to the contact list on Cisco Jabber client applications and on third-party client applications.
Users who reach the maximum number of contacts are unable to add new contacts to their contact list, nor can other users add them as a contact. If a user is close to the maximum contact list size, and the user adds a group of contacts that pushes the contact list over the maximum number, IM and Presence Service does not add the surplus contacts. For example, if the maximum contact list size on IM and Presence Service is 200. A user has 195 contacts and attempts to add 6 new contacts to the list, IM and Presence Service adds five contacts and does not add the sixth contact.
The System Troubleshooter in Cisco Unified CM IM and Presence Administration indicates if there are users who have reached the contact list limit.