Re: [Linuxptp-users] neither machine acknowledges the other

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

Hi,

On Wed, 2015-02-11 at 19:34 +0000, Bryan Yeung wrote:
> Hello,
> 
> I'm trying to setup PTP with software timestamping between two machines on 
> my local network.
> 
> When running ptp4l, both machines end up assuming the grand master role 
> (i.e. I see this on both machines):
> ptp4l[1747.050]: PI servo: sync interval 1.000 kp 0.100 ki 0.001000
> ptp4l[1747.051]: eth0: SO_SELECT_ERR_QUEUE: Protocol not available
> ptp4l[1747.051]: port 1: INITIALIZING to LISTENING on INITIALIZE
> ptp4l[1747.051]: port 0: INITIALIZING to LISTENING on INITIALIZE
> ptp4l[1754.276]: port 1: announce timeout
> ptp4l[1754.276]: port 1: LISTENING to MASTER on 
> ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES
> ptp4l[1754.276]: selected best master clock 089e01.fffe.e6e911
> ptp4l[1754.276]: assuming the grand master role
> ptp4l[1754.277]: port 1: master tx announce timeout
> ptp4l[1754.277]: port 1: setting asCapable
> ptp4l[1755.277]: port 1: master sync timeout
> ptp4l[1756.277]: port 1: master sync timeout
> ptp4l[1756.278]: port 1: master tx announce timeout
> ptp4l[1757.277]: port 1: master sync timeout
> ptp4l[1758.277]: port 1: master sync timeout
> ptp4l[1758.278]: port 1: master tx announce timeout
> ...
> 
> 
> If I run tcpdump on either machine, I can see the messages from both 
> machines to the multicast address:
> 11:12:04.114210 IP 172.23.188.135.320 > ptp-primary.mcast.net.320: UDP, 
> length 64
> 11:12:04.235244 IP 172.23.188.213.319 > ptp-primary.mcast.net.319: UDP, 
> length 44
> 11:12:04.235294 IP 172.23.188.213.320 > ptp-primary.mcast.net.320: UDP, 
> length 44
> 11:12:04.450571 IP 172.23.188.213.319 > ptp-primary.mcast.net.319: UDP, 
> length 44
> 11:12:04.450620 IP 172.23.188.213.320 > ptp-primary.mcast.net.320: UDP, 
> length 44
> 11:12:04.451046 IP 172.23.188.213.320 > ptp-primary.mcast.net.320: UDP, 
> length 64
> 11:12:05.113616 IP 172.23.188.135.319 > ptp-primary.mcast.net.319: UDP, 
> length 44
> 11:12:05.113677 IP 172.23.188.135.320 > ptp-primary.mcast.net.320: UDP, 
> length 44
> 11:12:05.234128 IP 172.23.188.213.320 > ptp-primary.mcast.net.320: UDP, 
> length 64
> 
> 
> Any debugging tips or suggestions would be greatly appreciated.
> 
> 
> Thanks!
> 
> Bryan
> 
> 

Try ensuring any firewall (iptables, firewalld, etc) has allowed
multicast traffic. That's usually the symptom I see when the packets
arrive in tcpdump but not the application.

Regards,
Jake