CDI or UDS

[Greg Mora]

I am trying to understand the pros and cons of CDI and UDS directories. This is assuming that you are on-net and not going through expressway as I know you can only use UDS. 

Is there a difference in result response? (time, accuracy, etc.)

Better contact photo response? (Large amount of users are annoyed that directory groups don't show photos until you hover or show profile and that photos aren't simply cached when jabber creates local files) 

More reliable/consistent searching?

What does Cisco recommend? 

Thanks in advance! 

[Jonathan Schulenberg]

Neither contact source influnaces the cache behavior of the Jabber client - that’s a client limitation. Also, Enterprise Group size limits are documented:
“Presence is unsupported for contacts in enterprise groups of over 100 people who are IM-enabled, unless the user has other presence subscriptions for a contact.”
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/11_9/cjab_b_feature-configuration-for-cisco-jabber/cjab_b_feature-configuration-for-cisco-jabber_chapter_010.html

UDS is easier, at least at first glance, since you don’t have to worry about sizing the Domain Controllers to handle the Jabber ADSI/LDAP query load. Remember that every call - deskphone Control or softphone triggers a contact source query. The downside to UDS is that it has no native contact photo support (requires URI substitution), lacks otherTelephoneNumber field secondary lookup support, and has a non-trivial load on CUCM. For large implementations this sizing factor could impact cluster node count requirements, especially since there is no mechanism to restrict which node(s) handle UDS queries. FWIW- TelePresence endpoints also use UDS.

CDI is basically the opposite of that: LDAP handles query load directly - be careful about attribute indexing and GC replication.
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/jabber/11_9/cjab_b_parameters-reference-guide-jabber/cjab_b_parameters-reference-guide-jabber_chapter_01010.html#CJAB_RF_A590F694_00
It natively supports contact photos, assuming they are being maintained in the LDAP database, but won’t work for MRA-connected clients. One other feature of CDI is Ambiguous Name Resolution (ANR). This is more important if you want to be able to search for Enterprise Groups.

[Greg Mora]

@jonathan,
First off, thank you for your detailed reply.
Do you know where the requirements/recommendations could be found for Domain Controller sizing?
Also, I have seen videos such as the one linked below where it shows UDS contacts having to be searched, hovered, or brought up in "View Profile" in order for the photo to show up. Is this still a limitation in recent versions?
Users want to see all photos shown as soon as they log in, not have to wait or click on each contact to make it show up.

[Jonathan Schulenberg]

DC sizing is a Microsoft question; Cisco doesn’t attempt to cover that.

For UDS, photos load without requiring a hover so long as you stay within the stated product limitations.