honorific/humble forms of "desu"

Hi. I'd like to ask about the difference between "degozaimasu" and "deirasshaimasu". To my best knowledge, "degozaimasu" is the humble form, and "deirasshaimasu" is the honorific form. But I maybe wrong. (which is why I'm asking this. ^^) Thank you.

That's right.

If you are a waiter a very expensive restaurant and serving a dish to the guests (humble form):
- Kochira wa (XXX) de gozaimasu. (This dish is XXX.)

If you are introducing yourself (humble form), this would be the more natural expression:
- Zyzzyva to moushimasu.

If you are introducing your teacher/senior to someone else (honorific):
- XXX sensei de irasshaimasu. ABC daigaku no kyouju de irasshaimasu. (This is Prof. XXX. He is a professor at ABC univ.)