Hi RK,
A very simple test is do ping on your ecc system and note for latency or timeout during GUI termination.
If latency is high or timeout occurs and sesdion gets disconnected, then you know it's a network issue between host. This can be because of incorrect packet sizes or your network capacity. Also, try to put on a network trace and monitor for any network fluctuations.
As a member of SCN please close your answered and open threads.
Regards