Service Advertising Protocol

The Service Advertising Protocol, or SAP short, is a term used in computer science and is a protocol used on IPX networks for service discovery. It was originally, as well as IPX, Novell Inc. developed for NetWare.

Operation

The SAP works on the broadcast principle. Each server or host that offers a network service periodically sends an IPX broadcast onto the network. The SAP packet contains is the information which service is offered, such as the route to the host is and what MAC address the host has to offer this service. The clients cache this information locally so that they immediately know the appropriate network address, if necessary by one of the services offered. Alternatively, there is also the possibility of using an SAP request, also a broadcast across the network to inquire whether a particular service is delivered to the client.

The special feature of SAP broadcasts is that they are routed, and are not, as is usual, restricted to the respective local network segment.

Criticism

At its launch, the SAP was a good invention that represented a certain type of plug and play, because you had to worry about the configuration of the clients on an IPX network no thoughts. Some time later, but was also the problem that lay behind the principle of network-wide broadcasts. The default time period for a SAP broadcast had been set from Novell to 60 seconds. So in the ever-expanding networks, it soon came into regular broadcast storms, as each network printer, each server, each router and sometimes some clients on the network services offered. In later TCP / IP-based versions of NetWare, the SAP, through the Service Location Protocol (SLP) has been replaced.

• Network protocol
• NetWare