Re: [Linuxptp-users] Issue when partner machine reboots

[Keller, J. E <jac...@in...>]

> -----Original Message-----
> From: Richard Cochran [mailto:ric...@gm...]
> Sent: Friday, May 04, 2012 11:29 PM
> To: Keller, Jacob E
> Cc: lin...@li...
> Subject: Re: [Linuxptp-users] Issue when partner machine reboots
> 
> On Fri, May 04, 2012 at 08:39:36PM +0000, Keller, Jacob E wrote:
> >
> > Ok. For now I had validation try using the l2 ethernet packets. Reset
> > doesn't make these invalid. I believe the reason why UDP sockets go
> > down is because the IP address becomes invalid when the socket loses
> > link. (Even if the same IP address came back!) I like the idea of a
> > netlink socket that could trigger a proper port reset. Right now the
> > default port reset doesn't appear to reset the socket. (It does get a
> > fault because it is unable to transmit,but the socket isn't
> 
> ^^^^^^^^^^^^^^^^^^^^
> > reset when it clears the fault.)
>  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> /
> This surprises me.
> 
> After a port fault, the clock waits 15 seconds and then clears the fault. This
> causes the port to open the transport (ie socket) again.
> So if the program faults after a failed transmission, then it should recover.
> Could it be that your network setup loses the default gateway after linkdown?
> (Without a default route, the UDP multicast does not
> work.)
> 
> In any case, if your UDP socket does recover after a failed transmission, then
> there is a bug somewhere. I expect that ptp4l should reset (close, and then
> open) the UDP socket for that port every fifteen seconds, until the link
> recovers. If this isn't working, then I want to know why.
> 
> There is _one_ case where I know that the port gets stuck, and that is when
> you have slave only mode. If the link does down when the port is in the
> listening state, the port never sends and thus never sees and error. For this
> case the netlink socket is needed.
> 
> Thanks,
> Richard

We were seeing faults. It is possible the default gateway goes down, but it should
Come back after the link returns, right? There was no slave only mode. So the reset
Process does close and open the socket again? I will see if I can narrow this down.

- Jake