SSL client certification LDAP authorization

The capability exists in LTM because of the inclusion of a legacy component called the Advanced Client Authentication (ACA) module. ACA is a feature module, the predecessor of APM, and is generally rolled into enterprise (and some other) licensing options. It is, first and foremost, a legacy product that will fade from existence in future BIG-IP releases. So while you can perform the required LDAP authorization with ACA now, it shouldn't be a long-term solution.