Thursday, October 22, 2015

Google Fiber - EdgeRouter IGMP Proxy for TV Service

In my first blog post about switching to the Uqituiti EdgeRouter I noted that users with TV service would have issues running Atlantisman's TV script as is after running the modified script I posted.

I've modified the TV script he created so it will work with the IPv6 script I posted before.
Disclaimer: I don't have TV service, so I have no way to verify that this script actually works.

Modified TV Script

If you have the first gen Google Fiber equipment, attach your Storage Box (GFMS100) to your LAN and your TV boxes should work again.

If you have the second gen Google Fiber equipment things are more complicated because you have a combined Network and Storage Box in the Network+ box (GFRG200, GFRG210).

There are two options to get TV working with the second gen Network+ boxes:

First Option - 

  • Plug a switch into the Fiber Jack and connect both the EdgeRouter and Network+ box to the switch. 

There are a couple problems with this option though:
First problem, by connecting two routers to the Fiber Jack you'll be assigned two public IPv4 addresses. While Google Fiber currently allows this, in the future it will probably be restricted to only one IPv4 address and this option will no longer work.

Second problem, Google Fiber already restricts IPv6 address assignment and prefix delegation to one MAC address or DUID (DHCP Unique Identifier) per Fiber Jack. What this means is the Network+ Box will almost always win the race to get an IPv6 address and prefix before the EdgeRouter and the EdgeRouter will be stuck with only IPv4 connectivity and the CPU at 100% as the DHCPv6-PD process tries in vain to get an IPv6 address and prefix. By powering on the EdgeRouter first waiting a few minutes then powering on the Network+ box you can get around this issue.

Second Option - 

  • Login to and in the Advanced drop down for your network box change the "Router LAN IPv4 address", "DHCP start address", and "DHCP end address" to be on a different network than the LAN side of your EdgeRouter. (e.g. Change to, etc)
  • Plug the Network+ box into the LAN side of the EdgeRouter
Advantages of this option:
With this option you won't have to rely on a second IPv4 address that may go away or need another switch or vlan connected to the Fiber Jack. 
You can continue to use the wireless from the Network+ until your real access point arrives. :)

Current issues with this option:
Devices plugged into the Network+ won't receive an IPv6 address.
Devices plugged into the Network+ box will be going through a double IPv4 NAT.

Other Important Notes:
If you have a switch connected to the LAN side of the EdgeRouter and plan to connect your own wireless access point later, make sure your switch supports IGMP snooping and that you have it enabled/configured. The TV channels are multicast to the Network+ box/Storage Box and a switch without IGMP snooping will flood the traffic out all ports on the same vlan. (All ports if it's an unmanaged switch.) You can also put your WAP on the third EdgeRouter port and leave IGMP proxy disabled on it to get around this issue.

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