[Jack-Devel] AVB Backend

Chris Caudle chris at chriscaudle.org
Wed Jun 19 22:31:21 CEST 2019

On Wed, June 19, 2019 3:12 pm, Ethan Funk wrote:
> I was under the impression...that the AVB's
> precision network time management allows all devices to share a sample
> clock.

That is correct for AVB as well as for the other RTP/IP (layer 3) based
transports such as Dante, Livewire, Ravenna, etc.

> No asynchronous re-sampling would be required


> I am not clear how one goes about setting up which
> device on the network is the clock master

If you have access to IEEE specs see IEEE 1588-2008 and IEEE 802.1AS.
802.1AS is a profile of 1588-2008, there is what is known as "best master
clock algorithm" to select the best clock.  If multiple devices are
advertising equivalent quality ranking there is a tie breaker, I think
based on MAC address, but don't  quote that, I am going from memory and
have not looked at the details in quite a while.

Chris Caudle

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