Hi Anoop
There actually isn't an upper limit on how many tunnels you can create on a MSR router.
But you have to keep in mind that there are limits imposed by the hardware of the router (CPU, Memory, Encryption capacity) and they have a great impact on the tunnels you create.
With special testing equipment HP got more than 2000 VPN tunnels up on a MSR 920 router (which is one of the smallest of the entire MSR series).
The only upper limitation that exists is on the HP DVPN (Dynamic VPN) architecture. A VAM server (the DVPN central hub) can accept connections from up to 30.000 VAM clients (spokes).
But this number is also dependent on CPU and Memory of the router and, frankly, I have yet to see a VPN network with one single entry point and more than 5000 users.
Regards,
Alex