the functions are based on user licenses not server or application based. But you don't need to install and configure the other applications. But check out the feature table of the licenses. A lot of stuff is always included and you could use it.
You will find details about the licensing here: http://www.cisco.com/c/en/us/products/collateral/unified-communications/unified-communications-licensing/product_solution_overview0900aecd806cc7a4.html
Be aware that you need for some phone types a minimum license(table 2).
You could install the subscriber on the same server as the publisher.But yeah, that is only a software redundancy. So for a real physical redundancy you will need a second server, but there is no additional license necessary.
you have copied the URL of an outdated version of the BE6000. We are at v. 10.5 now, and starting from 10.0 device licenses have been dismissed. The only necessary licenses are the 5 types of UCL or UWL, namely: UCL Essential, UCL Basic, UCL Enhanced or Enhanced Plus, UWL Standard, UWL Professional. They include different levels of rights and entitle each user to use 1 only device (UCL ess. and basic), 2 devices (UCL Enhanced Plus) or up to 10 devices (UWL licenses). Also, the type of device allowed by each license type is different: for instance, video-phones are only allowed by UWL licenses. UWL also include Voicemail (you can add VMs to UCL licenses by dedicated licenses).
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