AVB – Traffic Classes

AVB – Traffic Classes

The traffic in an AVB Network is classified into Class-A, Class-B, Control Traffic, and the rest as Best-Effort. These streams are identified by, unique (application generated) Stream-ID, destination Multicast MAC address, and classified based on VLAN ID and priority. Each stream defines the worst-case packet-size, frequency of such packets so that the intermediate nodes know the amount of bandwidth to be reserved to deliver them to the listener(s).

Needless to say, the Audio/Video streams are mapped to the highest priority traffic classes A/B, which are:

  • Class-A streams: Produce frame(s) at 8 KHz (or 125 micro-seconds) and support an end-to-end latency of 2 milliseconds.
  • Class-B streams: Produce frame(s) at 4 KHz (or 250 micro-seconds) and support an end-to-end latency of 50 milliseconds.

This is followed (in priority) by Control Traffic. The control-plane traffic is important for all the state-machines and signaling, however, are not as much latency-bounded as the AV streams. The control traffic is also mostly event-based, majorly non-periodic and much smaller in volume when compared to the AV and other data-traffic. This includes PTP control frames, MSRP BPDUs and other protocol exchange like IGMP and multicast etc.


...that's not all folks!

To continue reading the article, please Login/Register

(c) AVChrono 2021, All Rights Reserved

AV Chrono

Back to top
You cannot copy content of this page
%d bloggers like this: