This read-write INTEGER (1-255) determines the data link layer protocol configured on a given port of the CX device, with the source listing enumerated options such as ethernet(6), token_ring(9), frame_relay(32), and voice(100), and the setting takes effect immediately once written. An administrator would set this value when provisioning or repurposing a port, for instance converting a port from one interface type to another as physical modules or requirements change. For example, writing the value 6 to this object on a given port would configure that port for Ethernet, while writing 32 would configure it for Frame Relay instead.