A question about 802.16( Wireless MAN)

Hello everyone here.I am doing some researches about IEEE 802.16
Wireless MAN now. I'd like to share ideas with anyone who is also
interested in it.
I am focus on the MAC layer.After reading some materials about it, I
still not so confirmative with the following idea:
What's the relationship between CID and MAC PDU?
In my opnion, one particular CID can be assigned to several MAC PDUs in
an SS,and these PDUs with same CID are transmitted in bursts from this
SS.But in one burst there are many PDUs with different CIDs from the
same SS.
And I think it is just those PDUs transmitted in consecutive bursts and
owning a same CID who consist the concept of Service Flow.
Am I right?