We get a lot of these alerts. The actual tns ping time ranges from oh 500 to 5000 msec. Now in practice we don't experience this. I can do tnsping from my PC (or from the Grid Control host) to these target databases and get the nice snappy 10ms or 20ms I would expect. I think our network is performing well. But, these alerts keep showing up.
Any thoughts on the cause? If I'm fairly confident that the network layer is OK, should I be looking at performance problems at the target? Or, could it be the Grid Control host itself that's having trouble?
Did you once "reload" your listener or some similar administration task? If you do for example a "lsnrctl reload" on the server, it is quite acceptable to have 5000 msec on the client at that time. Remember this is a maximum value, not an average.