3.1.3.1.1 Table of Security Providers
Table of Security Providers: A server implementation MUST maintain an abstraction of a Table of Security Providers indexed by Security Provider value as defined in section 2.2.1.1.7. The table MUST have fields for security provider and principal name.
Higher-level protocols indicate to the RPC runtime when to add rows to the Table of Security Providers using implementation-specific APIs. Once a row has been added to the Table of Security Providers it cannot be removed or modified.
Many PDUs that arrive at a server have a field that selects a Security Provider (also called an authentication type). These extensions MUST use the Security Provider in the PDU as a selector in the Table of Security Providers to route the PDU for processing to the correct security provider.