This read-write field tells the switch whether the attached CPE device supports the DXI heartbeat polling mechanism, letting the switch know whether to expect and send heartbeat exchanges on this SMDS/DXI interface. An admin sets this based on the actual CPE's capability; setting it to poll for a device that does not support heartbeats would cause the switch to expect responses that never arrive, potentially triggering unnecessary link-down declarations. For example, older or simpler CPE routers lacking heartbeat support would require lportSmdsCpePoll set to nopoll(1) to avoid the switch flagging a healthy but non-heartbeat-capable device as failed.