I have a Linksys WRT150N router running DD-WRT (Linux based router OS, original Linksys OS was crap). Because my ISP uses separate networks for IPTV and Internet, I had to connect IPTV network cable to a LAN port on my router for IPTV to work. But that created a major problem. My wireless and LAN was constantly being flooded with IPTV multicast data (at ~4.5Mbits), regardless if the IPTV player program on my PC was running or not.
This flood of IPTV data rendered my Wireless network useless because it could not serve the Internet properly due to being constantly flooded with data (it was nearly impossible to connect and the speed was < 10KB/s).
I’ve found a solution on Google. It suggested creating separate VLANs (Virtual LANs) for IPTV and the rest of the network, thus separating IPTV port from the rest of the network, and redirecting data from IPTV port to the rest of the network through HTTP.

I thought I would create a separate VLAN for IPTV . But on DD-WRT site, they say that my router does not support VLAN.
But when searching the forums I’ve found out that my router does indeed support VLAN (I have a newer hardware revision), but I need to update to the latest SVN (subversion) build of DD-WRT and I need to enable VLAN function from the shell.
I’ve successfully created two separate VLANs, one for IPTV port and one for all other ports and blocked multicast data from going outside IPTV VLAN.
I’ve loaded udpxy to my router to forward IPTV data from IPTV VLAN to main VLAN through http.
Now when I watch TV on my PC, IPTV data only goes to the PC on which I’m watching TV.
Now my wireless and LAN is no longer being flooded with IPTV data. I guess wireless should now work fine too, but I have no laptop or a working wireless card to test it.