So far I am aware of, after connecting to VPN I get new IP from its service; assuming no DNS leaks etc. all network goes trough encrypted channel.
Can my ISP see my new IP when I am connected to VPN?
If so, then it's security flaw which can be easily tracked back to me, which defeat purpose of using VPN.
The entire idea of gateway tunneling (over VPN in your case) is that any traffic flowing through the VPN is only visible to you. Hereby I'd assume the 'new IP' is nothing more than a temporary ip to exit the remote site towards the internet.
On the other hand you're ISP can always see where the VPN connection is going to, since there needs to be some sort of connection in order to tunnel traffic.
The VPN is an established connection between your router and the destination router that has its information packaged in an extra layer of TCP/IP protocol. The ISP provides your public interface ip address on the router, which all traffic flows through. All internal traffic which uses the private IP range of addresses gets its addresses changed by your router to the public address with a unique port number, so when responses come back the router knows what device to send it to. So no the ISP sees nothing that is setup on your router, therefore knows nothing about lower levels in the TCP/IP protocol that involve the VPN packaging
