ZOB RADAR CTLR ISSUES DSCNT CLRNC TO A320 AND XFERS COM TO THE NEXT SECTOR; THEN DSNDS A DC8 TO THE EXPECTED VACATED ALT. THE A320 DOES NOT DSND INITIALLY AND WHEN IT DOES; INITIATES A TCASII CLB BACK TO PREVIOUS ALT; CONFLICTING WITH DSNDING DC8.

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2 ACFT IN THE SECTOR ABOVE OURS WERE BEING VECTORED AND DSNDED. ACFT X CAME ON OUR FREQ RPTING LEVEL AT FL270. I DID NOT HEAR THIS DUE TO BEING BUSY WITH MY D-SIDE DUTIES. WHEN I LOOKED AT THE RADAR; I NOTICED THE DATA BLOCK SHOWED FL270 DSNDING TO FL240. THE RADAR CTLR DID NOT ASK ME TO COORDINATE FOR LOWER WITH THE PREVIOUS CTLR; SO I DID NOT KNOW THAT HE WAS LEVEL AT FL270 AND NOT IN A DSCNT. I THEN OVERHEARD THE PREVIOUS RADAR CTLR CALL THE RADAR CTLR AT MY SECTOR AND ASK HIM TO PUSH ACFT #1 DOWN. THE RADAR CTLR ATTEMPTED TO DO SO; CALLING THE ACFT SEVERAL TIMES WITH A DSCNT CLRNC; BUT ACFT #1 WOULD NOT ANSWER. WHEN THE ACFT DID ANSWER; HE STATED HE WAS RESPONDING TO A TCASII RA AND WAS CLBING. AT VIRTUALLY THE SAME TIME THE CONFLICT ALERT ACTIVATED SHOWING ANOTHER ACFT AT FL270. I IMMEDIATELY NOTIFIED THE PREVIOUS RADAR CTLR OF THE TCASII RA RESPONSE AND THAT THE ACFT WAS CLBING. SUPPLEMENTAL INFO FROM ACN 422864: ACFT #1 HAD BEEN VECTORED FOR IN TRAIL SPACING. HE HAD ALSO BEEN STEPPED DOWN ON ALT BECAUSE OF OTHER TFC. ACFT #1 WAS GIVEN A HDG FOR THE DXO 147 DEG RADIAL AND DSNDED FROM FL270 TO FL240; ASSIGNED AN AIRSPD AND COMS XFER TO FREQ 127.9. ACFT #2 AT FL280 WAS GIVEN DSCNT TO FL270 TO START DSCNT INTO DAY. ACFT #1 CHKED IN AND THE CALL SIGN HAD TO BE VERIFIED. I NOTICED ACFT #1 HAD NOT DSNDED TO FL240. CALLED CRL CTL POS TO GET ACFT #1 'PUSHED' DOWN. CRL D-SIDE CALLED TO SAY ACFT #1 HAD AN RA AND WAS CLBING. ACFT #2 WAS ASSIGNED FL280; HDG; THEN DSNDED TO FL260. SEVERAL ACFT HAD TO BE REISSUED CLRNCS. SUPPLEMENTAL INFO FROM ACN 422865: ACFT #1 WAS GIVEN A DSCNT CLRNC AND A TURN. ACFT #1 READ BACK THE TURN BUT NOT THE DSCNT. ACFT #1 CONTINUED TO FLY AT THAT ALT FOR 20 MI. WITH ONLY 15 MI TO THE INTXN THAT THE ACFT HAD TO CROSS AT 12000 FT (ON APCH PLATE); I WOULD HAVE THOUGHT THE PLT WOULD HAVE ASKED FOR LOWER.