ExtremeSwitching (EXOS)

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Is there a way to know why some gPTP packets are discarded?

  • 1.  Is there a way to know why some gPTP packets are discarded?

    Posted 06-15-2016 17:18
    I have a Summit X670 switch with the AVB package installed. When I look at the counters for a specific port with the command : show network-clock gptp counters, the stats indicate some discarded packets. Is there a command or a log that I can use to know the reason why these packets have been discarded? Thanks


  • 2.  RE: Is there a way to know why some gPTP packets are discarded?

    Posted 06-16-2016 10:52
    Sebastien,

    As far as I know there isn't a show command or log message that will indicate exactly why the packet was discarded. In the "show network-clock gptp port PORT_NUMBER counters" output there are three counters at the bottom "Announce Receipt Timeout Count", "Sync Receipt Timeout Count", and "Peer Delay Allowed Lost Response Exceeded Count". I believe each of these errors will also result in a gPTP packet discard. However, I am not certain if those are the only reasons. Commonly it is because of an issue with the peer delay measurement. The example below is from a port that has gPTP enabled, but is connected to a non gPTP capable device:

    L3L_K2_U32(65.24).6 # show network-clock gptp port 2 counters
    Port number : 2
    gPTP port status : Enabled
    ------------------------------------------------------------
    Parameter Receive Transmit
    ------------------------------------------------------------
    Announce 0 0
    Sync 0 0
    Follow Up 0 0
    Peer Delay Request 0 172
    Peer Delay Response 0 0
    Peer Delay Response Follow Up 0 0
    gPTP packet discards 172 -
    ------------------------------------------------------------
    Announce Receipt Timeout Count : 0
    Sync Receipt Timeout Count : 0
    Peer Delay Allowed Lost Response Exceeded Count : 172 [/code]
    As you can see, the discard counter directly matches the Peer Delay Allowed Response Exceeded Count.


  • 3.  RE: Is there a way to know why some gPTP packets are discarded?

    Posted 06-16-2016 13:08
    Thanks for the answer