Re: [Linuxptp-users] Issue in 802.1AS

[Richard C. <ric...@gm...>]

On Tue, Jul 16, 2013 at 11:17:02AM +0530, Aman Sharma wrote:
> Hi All,
> 
> We are running gPTP between two linux machines having Broadcom switch as a
> intermidate device.In this Broadcom switch also support gPTP i.e 802.1AS
> .So in this case Broadcom switch act as a P2P transparent clock with Port 1
> and Port 2.Port 1 is connected to Laptop_1 and Port 2 is connected to
> Laptop_2.
> 
> When running* Laptop_1 :- Master mode* and  *Laptop_2 :- Slave mode*
> and *Broadcom
> switch :- P2P transparent clock*.
> 
> And Correction field is updated to the residence delay at the Laptop_2.

Um, you have Laptop_2 as an end station, and so it does not have any
residence delay at all.

> In this,My question is this : In The transparent clock, Port 1 act as
> Master mode and Port 2 act as slave mode.
> But I read that It will just send the Peer 2 peer delays packets and update
> the correction field according to the residence time.Means No master or
> slave mode are there in the Transparent clock.
> 
> *I want to know, whether gPTP supports boundary clock mode or not?*

There are no boundary clocks in gPTP, just bridges and end stations.

But ptp4l does work as an end station together with bridges. I have
tested it with the Titanium 411 AVB Ethernet Bridge. I don't have a
Broadcom bridge to test, but ptp4l should work with it.

HTH,
Richard