The helpful informations:
With CO services the signaling point code of the receiver is determined by means of the DPC in the Routing Label, and the receiver distributes messages internally according to the local reference. No further addresses occur in the DT1, RLSD, and RLC….just the CR contains a receiver adress. Therefore, CO services can be used only if the MTP is able to determine the message destination from the DPC.
With GSM, CO SCCP services occur at A-interface (BSS-SSS).