based on Internet Protocol which has disadvantages in speed
expansibility and quality of service etc.Accordingly
we bring forward a solution of VPN on Multiprotocol Iabel Switching (MPIS) backbone network. We introduce Certificate Authority (CA) in this solution because both MPLS and IPSec haven't made a clear definition of authorizing identity. Taking advantages of MPLS in transporting efficiency
authorizing identity by CA
exchanging keys by Internet Key Exchange Protocol (IKE) and encrypting data by IPSec protocol
we construct a secure and efficient VPN on MPLS backbone network. Fmthemnore
we describe the realization of every component of MPIS VPN in detail.