I am also having TNSPING response time issues.
We have intermittent times when it goes from 0-20 msecs to 10000+ msecs and back to 0-20 range. I checked the DNS lookup portion, and it is consistently under 1 second. So what is making the TNS listener take more than 10 seconds to respond?
The database is a single node, so there isn't a clustering issue, and the server itself isn't that busy (or resource bound).
I notice the same behavior on many different databases, all are 11gr2. Some are clustered, some are not. We've done extensive packet analysis, and determined that the latency is with the TNS listener or DB. Any ideas?