VPN issue

We have found that our employees that have Xfinity home internet cannot stay connected to our VPN, all other employees that have other internet service providers work fine.  After running ping and tracert tests on the Xfinity home internet we have found that it runs a steady 25 pings and then goes into expired on transit for about 25 pings.  This explains why the users can only stay connected to the VPN for about 30 seconds.  If you are having problems with your VPN intermittently disconnecting try running a ping -t test or a tracert to see if there is an internet connection problem.  We have reported this problem to Xfinity support and are awaiting a response.