[Linuxptp-users] neither machine acknowledges the other

[Bryan Y. <br...@gm...>]

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