GPTP change of dest address

Sub forums for various specialist XMOS applications. e.g. USB audio, motor control and robotics.
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lokesh327
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Posts: 29
Joined: Wed Feb 06, 2013 2:24 pm

GPTP change of dest address

Post by lokesh327 »

Hello,

I am working with AVB_LC_BRD where I use two boards for streaming audio over ethernet.

I use one as Grandmaster and the other as slave which synchronizes the time using grandmaster.

I am also working on ptp time synchronisation. During my research, i came to know that I can also change the "dest_mac_addr" (from 0x01, 0x80, 0xc2, 0x0, 0x0, 0xe to grand master device mac address), so that all my ptp req messages directly goes to the grandmaster device and receives response message.

So far the system is working fine, I just want to know whether the use of this functionality is illegal or does this have any side effects.

Please let me know.


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Andy
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Posts: 279
Joined: Fri Dec 11, 2009 1:34 pm

Post by Andy »

Hi,

I would not recommend changing the PTP destination MAC address. It is a reserved multicast MAC address that is handled in a special way by AVB switches.

Perhaps your problem is that you are not using an AVB switch? The PTP packets may be broadcast on a non-AVB switch because it does not know how to handle them.
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