Before you configure inter-PSD forwarding, remember that each PSD that uses inter-PSD forwarding must have a tunnel PIC available to it. To configure the cross connection between PSDs, a new interface type, xt, is implemented in JUNOS Release 9.5. All PSDs configured for inter-PSD forwarding must be running JUNOS Release 9.5 or later. Currently, only frame-relay encapsulation is supported for inter-PSD forwarding.