IM&P - UC Service and Service Profile - Why?

[C_Noble]

Thank you for reading.  I have several IM&P related questions.  My environment and questions are below:

Call Manager / IM&P
11.5(1)SU8
On-Prem - Single Cluster
2 Node IM&P cluster
ADFS SSO Enabled
Using UDS
Jabber for Windows

Question 1 : After configuring IM&P, my Jabber client was unable to find its services and login.  I created a non-default UC Servie Profile and then the client was able to login.  What is the purpose specifying a UC Service and associated Service Profile (User Management > User Settings > UC Service and Service Profile)?  Shouldn't the blank system default service profile suffice?

Question 2 : What is the appropriate value for the HostName/IP Address field when specifying the UC Service?  The page help documentation states : "This value must exactly match the host name, IP address, or DNS SRV of the associated IM and Presence service." It also states, "Cisco recommends DNS SRV to help the client find the correct IM and Presence service for the user."  Doesn't the client already know the service via the SRV lookup made from the host machine?

Question 3 : Assuming my domain where company123.com, would the value of the HostName/IP Address field be _cisco-uds._tcp.company123.com ?

[Jaime Valencia · Accepted solution]

Have you gone through the Jabber documentation?

https://www.cisco.com/c/en/us/support/unified-communications/jabber-windows/products-installation-guides-list.html

They explain why you create UC services and services profiles, SRVs needed, etc.

[C_Noble]

Admittedly I only glossed over the Jabber documentation, but I read all of the IM&P documentation.  I will look there for my answers and write back if I cannot find what I am looking for.  Thank you for pointing me in the right direction.