Rules for cross-network session request routing

The rules for routing cross-network session requests are as follows:

The request is not routed if its visit count (SSCP rerouting count) has reached 0.
The request is never routed back to the SSCP from which it was received.
The request is never routed back to its originating SSCP.
The request is never routed in this network if it was received from an SSCP in this network.
An SSCP receiving a session request from another network can route the request to a different SSCP in that network through a different gateway NCP. It cannot route the request back using the same gateway NCP.
The request received by a nongateway SSCP cannot be rerouted by that SSCP.
The cross-network request received by a gateway-capable SSCP can be rerouted by that SSCP.
A nongateway SSCP can perform trial-and-error routing for a session that it initiated.
If the real NETID of the DLU is known, routing is not attempted to a nongateway SSCP with a different NETID, unless the adjacent SSCP supports the nonnative network connection function.
A request is not routed to an SSCP that does not support the required function. (For example, automatic logon sessions are not routed to SSCPs that do not support automatic logon sessions.)