Hi Ian,
there is a known issue with VCS X6.0 where if a remote client (Such as TMS) attempts to connect to the VCS using a source port in the range 4369-4380, the VCS will not respond the way it should, which causes the connection attempt to fail.
For TMS, which runs on Windows, this will result in an intermittent connection loss towards the VCS, since TMS (Windows) in the case of a failed connection attempt will increment the source port and make a new attempt, which means that TMS will make 12 unsuccessful attempts in connecting to the VCS before it can successfully establish a connection again. TMS will use approximately two minutes to increment through this port range, and connectivity should be re-established again once it has incremented past the affected source port range.
A fix for this issue will most likely be included in the upcoming X6.1 software which is due for release soon.
It is of course possible that the problem you are experiencing could be caused by something else rather than this purticular issue, but the symptoms of this known bug are quite distinct and can easily be identified by performing a network capture (Using Wireshark for example) on TMS itself.
Hope this helps!
Andreas
