"跨地域企业网络设计与实现：VPN安全保障与高可靠性探究"

Abstract: The implementation of cross-regional enterprise network can be achieved through two main approaches, namely dedicated lines and the Internet. However, the high cost of dedicated lines has made many companies hesitant to adopt this solution, thus making Internet-based connectivity the most popular networking option. Due to the open nature of the Internet, it is essential to employ secure networking technologies to ensure the confidentiality and integrity of data transmission. This has led to the emergence of VPN technologies such as IPSEC OVER GRE and MPLS VPN, which combine various security protocols to enable secure data transmission while facilitating cross-regional network communication. Moreover, while ensuring the secure transmission of data across different regions, it is also crucial to maintain high reliability within the internal enterprise network. This paper leverages popular technologies such as Cisco's proprietary HSRP and PVST, as well as open MSTP and VRRP technologies to provide high redundancy. The design and configuration were achieved using the Cisco IOU simulator, and the test results validated that the network planning and design met the requirements of a large enterprise. Keywords: enterprise network, VPN, redundancy, load balancing.