The Service Advertising Protocol (SAP) is included in the Internetwork Packet Exchange (IPX) protocol.
SAP makes the process of adding and removing services on an IPX internetwork dynamic.
IPX network servers may use SAP to identify themselves by name and service type.
All entities that use SAP must broadcast a name and Service Type that (together) are unique throughout the entire IPX internetwork.
This policy is enforced by system administrators and application developers.