Groups mobile devices based on the network protocols (GPRS, CSD, EDGE, HSCSD, and so on) that they support. The report also includes an Unknown group for unidentified network protocols.
When a visitor uses a mobile device to access your site, the Net Protocols report increments by at least one. If the phone supports multiple network protocols then each of those groups in the report increments. Because of this, the sum of the groups might be greater than the total shown at the bottom of the report.