Frequently asked questions

What is Auxiliary data?

SuperMAC and HyperMAC also have the in-built capability to relay control data, including TCP/IP and similar IP-based data packets, at data rates of 5 Mbit/s and 200 Mbit/s respectively. In both cases, part of the transmission system is specifically allocated to carry control data, but is transparent in operation at the external Ethernet interfaces. As a fixed capacity is allocated to the control data, there is no risk of the audio streams being swamped by control data messages. The control data packet contents are irrelevant to the operation of the SuperMAC and HyperMAC audio streams, so any format of control message received can be relayed.

SuperMAC and HyperMAC employ different methods for transmitting the auxiliary data. SuperMAC embeds the auxiliary data in the same frame as the audio data. HyperMAC implements separate control frames for the auxiliary data, distinct from the audio data frames. These separate control frames allow full Ethernet packets to be transmitted, allowing connection to a conventional Ethernet switch or router for the transmission of auxiliary data in TCP/IP format.

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