This object indicates whether a given IPsec VPN tunnel on the Juniper device was established using policy-based routing (traffic matched against security policies) or route-based routing (traffic sent through a dedicated virtual tunnel interface). Administrators check this to understand how traffic is being steered into the tunnel, since the two approaches are configured and troubleshot differently. For example, seeing this object report 'routeBased' would tell an admin the tunnel behaves like a virtual point-to-point link with its own interface, rather than being triggered by matching policy rules.