aggregate connection “server and switch”

We are wondering, we want to take use 2 gig links from an x-
server, and hook them up to the 4006 core switch, to the gig
connections. .right now, we are using only 1 of these
connections with an ip of 172.17.200.12.. but we would like to
make 2 gig connection one FAT link to the switch.. now apple os
x has the ?link aggregate? to enable this, but im guessing its not
working because we have to enable something on the ?switch
side? if you have any info on how to do this, correctly, that
would be great, because we can afford some down time, because
it?s the summer, and students are not in, but soon enough, we
will have a school full of kids.

Thanks

Jeremy