In recent years

along with the MPLS VPN technology matures

its application is more and more widely.Most of the MPLS VPN technology is mainly applied in an AS domain

with the wide application of MPLS VPN in the same domain of AS

across MPLS VPN communication requirements of inter domain gradually increase. This article will through the implementation of the case of a cross domain MPLS VPN customer to carry on research

and propose a cross domain MPLS VPN implementation scheme in general.