This read-write INTEGER (src(1), all(2)) sets whether a port's QoS treatment for the voice VLAN applies only to traffic whose source MAC matches an OUI prefix, or to all traffic through that port. An admin chooses src(1) when a phone and a PC share the same port (via a pass-through switch on the phone) and only the phone's traffic should get voice QoS, or all(2) when every packet on a dedicated phone port should get that treatment. For example, setting src(1) on a port with a daisy-chained PC ensures the attached PC's traffic doesn't unfairly receive the phone's high-priority QoS.