Setting and Modifying the Routing Preference Protocol

When an SNA application initiates a session, Personal Communications must first determine which transport to use, either SNA, IP, or a combination of the two.

Personal Communications uses the default routing preference for the session unless there is a specific routing preference set for the partner LU. Personal Communications then sets up a session for the partner LU using the preferred transport.

If the partner is not available through the preferred transport, Personal Communications can reroute the session request over the other available transport, depending on the setting in the routing preference table. For example, if the setting in the routing preference table for the destination LU is nonnative first, Personal Communications will attempt to set up the session over TCP/IP. If the partner is not available through TCP/IP, Personal Communications will route the session over SNA. However, if the setting in the routing preference table for the destination LU is nonnative only, Personal Communications will attempt to set up the session over TCP/IP. If TCP/IP is not available, Personal Communications will not route the session over SNA, because the setting allows only Personal Communications to use nonnative transport.

The routing preference table is used only for new sessions. Previously existing sessions use the same transport; they are not brought down and rerouted if the routing preference table is changed.