This Uber Network1 shows a network involving two AV sources, a Cable Set Top box and a PC with a cable modem. This network segments the “External Network” from the “Internal Network”. You may want this type of network because you want to keep costs down, because it may be easy to run separate cable lines to the Modem and Set Top Box, or because you don’t want to block any incoming channels with the filter so that all channels are available for broadcast.