虛擬專網VPN 技術是近年來興起的一種新興技術，有很大的潛在市場價值。基于多協議標記交換（MPLS）網絡實現VPN 的技術方案大大改善了傳統IP 網絡的缺陷，同時又能提供和幀中繼/ATM 網絡一樣的安全性保證，很好地適應了VPN 業務的需求。本文介紹了MPLS VPN 網絡模型和工作原理，分析了兩種基于MPLS 網絡的二層VPN 技術實施方案，并比較優缺點。
關鍵詞： VPN；MPLS；網絡

Abstract： .The VPN technology is one of the development technology in recently, which is more valuable on business。MPLS network is greatly improved in tradition IP network’s disadvantage on realizing VPN technology plan，and can provide the safety guarantee same as Frame Relay/ATM network，so can fit for the VPN business demand 。This article introduces the MPLS VPN network model and principle ,analyzes two kind of the second layer VPN technology business plan basing on MPLS network ,and compare their advantage and disadvantage。
Key words： VPN；MPLS；Network