VPN with QoS Support in Mobile Environment

• Main Authors: Chao-Tung Liu, 柳晁棟
• Other Authors: Li-Der Chou
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/85446188661953709146

碩士 === 國立中央大學 === 資訊工程研究所 === 90 === Virtual Private Networks (VPN) support enterprises a secure and low-priced network environment. And as the wireless networks become more and more popular, more and more enterprise users can access the Internet anywhere, anytime using wireless technology. What comes after is the combination of VPN and the mobile environments. To achieve the mobile VPN environments, besides secure and on demand accessing the enterprise’s network, quality of service (QoS) is also an important issue. In IP VPN networks nowadays, differentiated service (DiffServ) is adopted to provide QoS network to network. But such scheme can’t guarantee end-to-end QoS of VPN services. The thesis proposes a two-level VPN bandwidth allocation strategy. VPN services are classified into VPN level and Call level. Bandwidth allocation of VPN level guarantee services of a group of VPN users, and the bandwidth allocation of call level let the users share the bandwidth allocated to the VPN. Besides, the proposed strategy also reserves the bandwidth of wired links or wireless channels before a user handoffs to ensure that VPN users can receive seamless services while roaming in the networks with consistent QoS. In the simulation results, we found that the proposed two-level VPN bandwidth allocation strategy can lower down the call blocking rate of call level services effectively, and the pre-reservation scheme can lower down the packet loss rate while users handoff.