How Port Forwarding Differs from Port Triggering
The following points summarize the differences between port forwarding and port triggering:
Port triggering can be used by any computer on your network, although only one computer can use it at a time.
Port forwarding is configured for a single computer on your network.
Port triggering does not need to know the computer's IP address in advance. The IP address is captured automatically.
Port forwarding requires that you specify the computer's IP address during configuration, and the IP address must never change.
Port triggering requires specific outbound traffic to open the inbound ports, and the triggered ports are closed after a period of no activity.
Port forwarding is always active and does not need to be triggered.
Fuente:
http://documentation.netgear.com/wgr614v9/enu/202-10308-01/WGR614v9-07-06.html