Different JAAS Ldap login module implementations?

Question

I have been implementing an out of the box JAAS LdapLoginModule for a Java 1.6 application. The implementation has gone smoothly except for a deployment to an IBM AIX platform. It would appear that the IBM Java runtime uses a different class path for LdapLoginModule.

The Sun class path is:

com.sun.security.auth.module.LdapLoginModule

The class path for an IBM Java runtime is:

com.ibm.security.auth.module.LdapLoginModule

So why is there a difference? I wouldn't expect there to be any platform specific implementation details for an LDAP protocol implementation.

Are there likely to be other platforms with different implemenations or class paths?