Comment Several different ways to skin this cat (Score 1) 383
One college I have gone to uses a separate domain for students from faculty and administration, @stu.college.edu versus college.edu. They use firstname.lastname, and then firstname.lastname#. They use Microsoft Exchange. Another college I attend now uses a unique ID created partly out of the firstname and a seemingly random 7-digit number, so John9999876@college.edu. This unique ID is also used to login to the student center to access registration, email, etc. It is different from the actual student ID number. As they use Google Mail, it may be generated by Google. My daughter's university also uses Google Mail, but she was allowed to create her own ID, firstinitialmiddleinitiallastname#.college.edu.
In business, I like to use firstname.lastname@business.com or firstinitialmiddleinitiallastname@business.com, with dupes using full first name or full middle name or both; sometimes using nicknames or fullnames, like bob vs. robert. I try to respect the preferences of the user if possible.
You could use any combination of these. You could use child domains based on named colleges within the university, such as wpcarey.asu.edu or engineering.stanford.edu. Or you could come up with an automatic random email ID generator or use mainframe login ID's, etc.