JSI Tip 7963. Certificate requirements when you use EAP-TLS and PEAP with EAP-TLS.

Microsoft Knowledge Base Article 814394 contains the following INTRODUCTION:

This article describes the requirements that your client certificates and your server certificates must meet when you use Extensible Authentication Protocol-Transport Layer Security (EAP-TLS) and Protected Extensible Authentication Protocol (PEAP) with EAP-TLS.