This read-write enumerated value determines whether the card treats this standard-ABR connection transparently, passing through RM cells that it assumes are generated by a TM4.0-compliant CPE (switchBehaviour), or as a terminating connection where the card itself generates the RM cells (srcDestBehaviour). Admins choose this based on whether the connected CPE itself implements ABR flow control or expects the switch to originate the ABR rate-management signaling on its behalf. For example, if the attached CPE is known not to be ABR/TM4.0-compliant, an admin would select srcDestBehaviour so the switch itself generates the necessary RM cells rather than assuming the CPE will.