This sectiondescribes the introduction to the Cloud Dedicated Access (CDA) product. CDA provides the connection service between users' local data centers and eSurfing Cloud Virtual Private Cloud (VPC). While making full use of the cloud-network integration advantages of eSurfing Cloud, the CDA product flexibly builds high-speed, low-latency, stable, and secure exclusive connection channels on and off the cloud relying on existing IT infrastructure.

Product Architecture

One end of the CDA dedicated physical line is connected to the local gateway equipment of the local data center, and the other end is connected to the CDA gateway, which connects the internal local area network (LAN) of the client's local data center to the access point of eSurfing Cloud and links the virtual private network (VPN) on eSurfing Cloud VPC to achieve safe, reliable, and high-speed intranet-level communication quality. The product architecture of CDA is shown in the following chart:

Differences between CDA and VPN Connections

Both CDA and VPN connections can connect the network between the user's local network and the eSurfing Cloud platform. However, they differ in some aspects. The table below shows the comparisons between CDA and VPN:

Comparison Item	CDA	VPN
Network Quality	CDA connects the user's local data center to the eSurfing Cloud data center using a dedicated physical line, thus ensuring a more reliable and low-latency connection.	VPN creates a secure encrypted channel through a public network (such as the Internet), allowing users to establish private connections between different locations.
Transmission Bandwidth	CDA is compatible with various underlying line types, such as IPRAN, MSTP, MPLS VPN, and OTN. It supports diverse port bandwidth specifications including 1 GB, 10 GB, 100 GB, etc. Furthermore, CDA provides port aggregation and link capabilities that enable on demand and elastic scaling of dedicated line bandwidth.	Limited by the bandwidth of the public network, that is, how much the Internet bandwidth is, the maximum transmission bandwidth of the VPN connection depends on the Internet bandwidth.
Security	CDA is physically isolated from the Internet. Users can select exclusive dedicated physical lines by exclusively occupying a physical port, thus ensuring high security and mitigating the risk of data leakage.	Encrypted communication based on the Internet can meet the security requirements of network transmission of general users.
Applicable Scenarios	CDA is suitable for connections that require a large amount of bandwidth with demanding stability and scalability, such as large-scale data migration and continuous data transmission.	VPN is suitable for temporary, small-scale connection needs.