This read-only value reports the negotiated UMTS Quality of Service SDU error ratio actually agreed with the mobile network for this connection. Since SDU error ratio reflects how many data units are allowed to be delivered corrupted or lost, an admin cares because a looser negotiated ratio than requested signals the carrier only guaranteed reduced data integrity for that session. For instance, if voice or telemetry traffic depends on a tight error tolerance and this object shows a coarser negotiated ratio, the admin should expect more retransmissions or degraded quality on that 3G backhaul link.