AppleTalk update-based routing protocol (AURP)

The functions of the AURP protocol(AppleTalkUpdate-basedRouting Protocol) are similar to those of the RTMP protocol(Routing Table Maintenance Protocol), whereby the AURP protocol only sends updates when changes occur. The AURP protocol is located at the transport layer.

The AURP protocol allows traffic in AppleTalk to be encapsulated in the header of another protocol. This allows two or more AppleTalk networks that are not directly contiguous to be connected to each other viatunneling over a foreign network. This connection is referred to as an AURP tunnel. In addition to encapsulation, the AURP protocol creates routing tables for the entire AppleTalk WAN by exchanging routing information.

An AURP tunnel operates as a virtual data link between two AppleTalk networks that are physically separated by another network, such as an IP network.