iChat In Pictures >> You are in Folder 8 Modem:Router and it's Sub Folder Linksys Router >> Page: Linksys UPnP
||5 Router UPnP
Essentially this pic is just to show you that UPnP can be anywhere in the menus that the manufaturers have set up on your device. On this device it is on the same page where you can change the Password for the device. When you compare this with the Thomson Alcatel's position of it's UPnP setting you will see it can be anywhere.
UPnP stands for Universal Plug and Play. It allows the Application to control the ports that are open in the modem or router. It also allows multiple computers to use the same ports at the same time. As DCHP can mean your computer gets new IP from the routing device, using UPnP means you do not have to turn off DHCP.
There are concerns with UPnP in that the routing device advertises that it is doing this. It tells other devices around it to a certain amount of "Hops" away from it. A Modem doing UPnP to Computer would be one hop. A modem doing UPnP through a router to a computer would be two hops. The Modem to the ISP's server is one hop. Some people feel that as the default is often 4 hops that the UPNP device can be "seen" over the Internet as It is one hop to the ISP and another to another end user using that same server. See this at WiKi It is worth reading the whole thing though.
A Final Word
With all of these different settings described in the last few pictures it is worth remembering that that there are faults or shortcomings and Risks with each one. In the end it is a question of balancing your Needs with the applications you use, on the computers you have, against the Risks that one method over another poses.
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