Anritsu FAQs

Unicast: In Unicast mode, the MT8860B transmits data packets that contain the MAC address of the DUT. For each correctly received data packet, the DUT responds by transmitting an ACK packet. The 802.11 standard states that the ACK must be transmitted within a short inter-frame space (SIFS). Consequently, after transmitting a data packet, the MT8860B waits for up to an "ACKtimeout" period for the ACK from the DUT. The length of the ACK timeout period equates to a SIFS period plus the length of an ACK packet. If an ACK is not detected then the MT8860B reference radio assumes that the packet has not been received correctly. The MT8860B then proceeds to transmit the next packet in the sequence. Unicast has the advantage to the user that the Packet Error Rate (PER) calculation is made entirely within the MT8860B and it is not necessary to use the DUT client software. The PER is calculated using the equation: PER (%) = [ (Packets transmitted by MT8860B - ACKs received by MT8860B) / Packets transmitted by MT8860B] x 100 Broadcast: In Broadcast mode, the MT8860B transmits a data packet with the address FF-FF-FF-FF-FF-FF. All devices (that are actively connected) must be capable of recognizing and receiving a data packet that contains the broadcast address. However, the device does not generate an ACK frame in response. Consequently, the PER is calculated by using the DUT client software to confirm that the received packet counter has been incremented. Although the user must use the client software, broadcast mode is suitable when connecting to and sequentially testing multiple units in a line. Broadcast also allows the user to check the receiver capabilities of the DUT without relying on the transmitter capabilities. Table and trace PER information is not displayed in broadcast mode and the user is notified of this when [Run] is clicked.