Complex sentence: The N-class servers were marketed as "Itanium-ready", although when the Itanium shipped, no Itanium upgrade was made avaliable for the N class.
Split into simpler sentences: The N-class servers were marketed as being "Itanium-ready". Although they were ready for Itanium, when it shipped Itanium wasn't ready for them, and no Itanium upgrade was ever issued for the N class.