NE870 pinging redundant controller
I`m running an upgrade where we are installing NE870 RNRP Router between Client/Server network and Control Network. RNRP seems to work fine, but the time on Connectivity Server(CNCP Slave) is not received from a Controller (CNCP Master) and it`s not possible to ping secondary controller ports(A.B.C+2.D IP Address).
From system 5.0 with a regular connectivity server configuration it`s possible to ping redundant controller IP Address and receive time sync from CNCP Master controller.
Does anyone have experience with NE870?
CNCP is a multicasted protocol, so the CNCP pulses sent by the AC 800M acting CNCP master will only reach to the NE870's control network interfaces, not any further.
Clock synchronization between HMI and AC 800M when using NE870 need to use SNTP (which uses unicast that can travel over a router).
About the ping problem:
1. Verify the backup address by pulling the controller log (default is backup interface disabled).
2. Verify that primary controller does not report "Primary: no communication with backup". Such warning will be raised if primary cannot "ping" secondary.
3. Verify that NE870 can ping backup controller (use web interface or SSH/CLI)
4. Verify that ICMP is not blocked in the firewall
5. Backup address, using default rule (0.0.+2.0) require a /22 network mask.
For the advanced user, a tcpdump can be attempted in NE870 to see where the ping fail.
# show iface
# tcpdump vlan1000 expr icmp
# tcpdump vlan1010 expr icmp
Replace vlanxxxx with the VLAN IDs used in your router (client/server/primary/secondary)
A ping can get stuck if "max no of hops" is exceeded, the default is 3 in AC 800M and max is 5, while a PC computer allow a maximum of 8. With only one router, 3 should be "more than enough".