CUCM and Unity is best centralized. Even if the WAN link goes down you can make your voicemail button dial into unity over the PSTN. The Presence server needs to be located next to the publisher, so should also be centralized.
As far as IPCCX you either choose to integrate it to CUCM OR to CME (could be CME / SRST). Generally I would say unless ALL of the agents are at that one particular site, to centralize it. The reason being is if its down you can alwawys configure CME/SRST and do some inbound hunt groups to suffice if the WAN is down. Rememeber SRST is going to be a very rare scenario, and things like email and such will be down because of this. Also you could always do some trickery in UCCX centralized in order to transfer over the PSTN in the case of a failure.
SIP traces provide key information in troubleshooting SIP Trunks, SIP
endpoints and other SIP related issues. Even though these traces are in
clear text, these texts can be gibberish unless you understand fully
what they mean. This document attempts to br...
Please find the attached HTML document, download and open it on your PC.
This provides an easy to use form where you simply answer a few
questions and it will render the proper jabber-config.xml file for you
to copy/paste. There is built in logic to verif...
CUCM Database Replication is an area in which Cisco customers and
partners have asked for more in-depth training in being able to properly
assess a replication problem and potentially resolve an issue without
involving TAC. This document discusses the bas...