@ GuyStandley
Yes it is. However, it has to be activated on each subsite you which to use it on. It does not support network wide activation.
Something else … Connections can be run in one of two modes on multisite. The first, by default, is multisite mode. This mode will have make it so each subsite that Connections is installed on will have its own directory. The second is, which has to be enabled, single-site mode on multisite. This mode will make it so all subsites in which Connections is activated will share the same directory. If you decide to enable the latter you should do so before entering data. Doing after would limit the data to the master site.
I hope that helps!
