[strongSwan] Keeping VPN tunnel active

[Fred]

Is there a way in Strongswan to tell it to keep a tunnel active?

I'm thinking here of devices, such as those running iOS, that do NOT 
have Always-On VPN easily available but where this behavour is desired. 
I'm not sure how Always On Vpn works anyway (is it proprietary?).Is 
there some standards compliant way of achieving this that will work 
across all devices (i.e. Windows clients, Android clients, iOS clients, 
Mac OS X)?

I see there is an auto=route option to install a trap policy 
responder-side but if the initiator is a road-warrior with dynamic IP 
and the traffic is always going out from road-warrior to strongswan 
responder would this work anyway?

Thanks.