What is the main purpose of a captive portal in network access?

The main purpose of a captive portal in network access is to force clients to undergo a specific access process. A captive portal typically presents a webpage that users must interact with before they can gain access to the internet or a specific network. This technique is often used in public Wi-Fi hotspots, where users may need to accept terms and conditions, log in, or provide personal information to authenticate their access.

This process ensures that access controls and security measures are in place, which can include stipulations regarding acceptable use or even payment models for internet access. By requiring users to go through this specific access process, network administrators can manage who accesses the network and under what conditions, thus maintaining a level of security and compliance.

The other options involve aspects of network performance or data management but do not accurately represent the primary function of a captive portal. For instance, while speeding up user authentication or optimizing data transfer speeds could be beneficial outcomes in some scenarios, they are not the core purpose of implementing a captive portal. Similarly, monitoring network usage statistics is important for network management but occurs after access is granted, rather than being an integral part of the initial access process facilitated by a captive portal.