https://www.cisco.com/c/en/us/support/docs/unified-communications/jabber-windows/118773-configure-kerbero The main advantage of Kerberos authentication compared to the other authentication methods is that you do not need to provide your credentials when you log in to Cisco Jabber. If you use Kerberos, the client does not prompt users for credentials, because authentication was already provided to gain access to the Windows desktop. This authentication method allows you to log in to Cisco Jabber with your Microsoft Windows login.

The scenario describes an issue where Message Waiting Indicators (MWIs) aren't lighting up for SIP-integrated Cisco Unity Connection users, even though calls reach voicemail. This points towards a configuration problem with MWI notifications on Cisco UCM.
* A. Modify the SIP Trunk Security Profile on Cisco UCM: While SIP trunk security is important, it likely wouldn't affect MWI functionality in this case.
* B. Increase the Delay Between Requests timer on Cisco Unity Connection: This setting might be used for other purposes but wouldn't directly address MWI notification issues on Cisco UCM.
* C. Assign a Calling Search Space to the SIP Trunk on Cisco UCM: Calling Search Space defines call routing, not MWI notification.