In large-scale networking with branch chains or branch offices, branch networks need to access the Internet, HQ, DCs, or other branches. In addition, branch networks may require private lines or VPNs for connecting to the HQ network. In this scenario where interconnection between branches and between branches and the HQ/DC is required, egress interconnection needs to be deployed for multi-campus/branch interconnection.

On a traditional campus network, branch networks connect to the HQ network through private lines, incurring high costs and low deployment efficiency. The coverage scope and network performance of the rapidly developing Internet improve continuously. This makes more and more enterprise branches access the HQ network by using the low-cost Internet. To ensure network security and reliability, IPsec VPN or SD-WAN needs to be deployed to enhance the security and efficiency of network transmission and increase reliability and flexibility of branch interconnection.

The CloudCampus Solution supports various types of devices and networking modes for interconnection between multiple campuses or branches. For ease of understanding, each campus or branch is called a site in the multi-campus/branch interconnection networking scenario. The internal networking solution of a site is the same as that of a single campus network. For details, see Single-Campus Networking Solution Design Guide. This section describes only the egress interconnection solution (that is, the site interconnection solution) design for multiple campuses or branches.