Packets
Four main types of packet are used in the transmission and synchronization of CobraNet:
- Beat packets – the conductor outputs a beat packet to all other CobraNet devices on the network at a rate of 750 packets per second. All other CobraNet devices on the network synchronize their audio clock and their data transmissions to the beat packet. The beat packet contains network operating parameters, clock data and transmission permissions for multicast and unicast bundles.
- Audio packets – also known as isochronous data packets, these packets are sent out by all CobraNet devices after they receive a beat packet. At standard latency settings, one audio packet is sent for each beat packet received, and each audio packet includes 64 samples of audio data per channel. At lower latency settings, audio packets may be sent twice or four times for each beat packet received. Bundles do not share packets; separate packets are sent in sequence for each bundle transmitted from the same device.
- Reservation packets – these packets are transmitted as needed or typically once per second at minimum. Their function is to control bandwidth allocation, initiate connections between CobraNet devices, and monitor the status of CobraNet devices.
- Serial bridge packets – asynchronous serial data may be sent between CobraNet devices on the same network. Many standard asynchronous serial formats are supported, including RS-232, RS-422, RS-485 and MIDI.
Read more about this topic: Cobranet, Transmission