Hi! We are trying to implement a NTP installation over a redundant network, connecting the stratum 2 servers to the stratum 3 clients. The precise situation is the following (compare with http://1stein.org/download/network.png):
3 networks, 192.168.3.0, 192.168.4.0, 192.168.5.0 ATOM1, ATOM2 - stratum 1 servers in network 3 GW1, GW2 - stratum 2 servers in all networks, i.e. 3, 4, 5 CLIENT1...CLIENTn - stratum 3 clients in network 4 and 5 Our goal is that GW1 and GW2 are always synchronized, even - if network 3 goes down, - or if one of networks 4 or 5 goes down, - or if the worst case happens that network 3 and 4 (or 5) go down and only one link is left between GW1, GW2 and the clients. We have configured the hosts in the following way: GW1 - with two IPs GW1_4, GW1_5 server 127.127.1.0 fudge stratum 5 server ATOM1 server ATOM2 peer GW2_4 peer GW2_5 GW2 - with two IPs GW2_4, GW2_5 server 127.127.1.0 fudge stratum 10 server ATOM1 server ATOM2 peer GW1_4 peer GW1_5 CLIENT1 ... CLIENTn server GW1 server GW2 The problem: If network 3 goes down, GW1 and GW2 select each other as their reference clock, one over network 4, one over network 5. The loop detection does not work here. The stratum of both references goes up poll by poll, until it reaches 16. Then one of GW1/GW2, say GW1, switches to the LOCAL(0) source. After the new stratum of GW1 propages to GW2 and back to GW1 (as stratum 7), GW1 switches back to GW2, even though the local clock's stratum is smaller. Then the game starts again that the stratum goes up by propagation. Solution 1: By removing one peer connection, we are able to remove the possible loop and it starts working, obviously by loosing some of the redundancy in network 4 and 5 which we do not want. Solution 2: We can also remove all peer statements and put "server GW1_4" and "server GW1_5" in GW2's config. But then we are lost if ATOM1 and ATOM2 are out of sync, because then it can happen that GW1 syncs to ATOM1 and GW2 to ATOM2, such that GW1 and GW2 are out of sync. But the latter _must not_ happen. Is there a way to tell xntpd to identify the IPs GW1_4, GW1_5 and GW2_4, GW2_5 such that the loop detection works? Can one force to use a common refid instead of the IP? Regards Stefan Schimanski _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
