Titles purchased through Serials may be found in Voyager Acquisitions by searching au+1st initial of each word, while titles purchsed through Acquistions (the more "book-like" serials) may be found by entering au+space+first word+space+second word, etc.
AU Library checks in serials and claims missing issues. Detailed workflows may be found in I:\AU Technical Services Department\Acquisitions Unit\Serials\Serials Check-In Specialist Files.
While we use EBSCO for most print serials subscriptions, it is best to supplement EBSCO claiming information with outside research -Ulrichs, publisher websites, etc. - for best results. (see links below)
We are members of USBE and offer them our unwanted issues. (see links below)
Always a good question...
An IBU is a bindable unit (i.e., 1 volume) that is missing one or more issues. We pursue various options for replacement, including verifying AU's access to a safe-house electronic option. We also maintain a cart of duplicate issues for our few multiple-copy orders in case the stacks copy vanishes.
Information may be found in "Finding replacement back issues" in I:\AU Technical Services Department\Acquisitions Unit\Serials
...and also in I:\AU Technical Services Department\Acquisitions Unit\Bindery\IBU - Incomplete Bindable Units
That is a CMT question and should be determined when the subscrption is requested, although the specifics of the binding unit (i.e., one volume, or one year, etc.) is at the discretion of the Processing and Serials Specialist and occurs once the title begins to arrive in-house.