This read-write INTEGER (src/all) controls whether Voice VLAN QoS treatment applies only to traffic whose source MAC matches a recognized phone OUI (src) or to all traffic passing through that port (all). An admin chooses src to give QoS priority only to genuine phone traffic sharing a port with a PC, or all when the entire port is dedicated to voice. For example, setting vlanVoicePortQosMode to src(1) on a port shared by a phone and a daisy-chained PC ensures only the phone's traffic gets the Voice VLAN's priority treatment.