A method for implementing a virtual leased line (VLL) is provided. The
method includes the steps of: configuring a virtual local area network
(VLAN) label stack on the basis of VLAN QinQ technique; configuring a
VLAN QinQ switching device and a multi-protocol label switching device to
communicate with each other; extending a label distribution protocol
(LDP) to support encapsulation of VLAN labels, so as to carry out VLAN
label assignment and take the extended LDP as a topology discovery
protocol for an L2 virtual private network; setting the range of VLAN
labels; implementing a VLL by constructing a VLAN switching path.