How to easily set up a redundant internet connection
When our DLS connection failed a couple of weeks ago, it became clear to me that we needed a backup of some sort. I looked into business DSL subscriptions, but if you need a fast guaranteed repair time, the monthly rates start to look like mortgage payments. That’s why I decided to get a second consumer broadband line and hook try to somehow tie them together into one, easy to use local network. Thanks to a great router by Draytek and some clever tips from various forums, this turned out not to be very difficult at all. Here’s what I did.
Dual WAN setup
First, get a second line
coax connectorMy primary connection is a DSL line, so I decided to get cable as a backup. A single telephone line can only be used by one provider at the same time, so I wouldn’t be able to get another DSL connection. But a more important reason is that even if you have two telephone lines, any failure in your local telephony network will probably still knock out both. By going for a completely separate infrastructure, I hope to avoid this.
Another option is to get a 3G USB modem. The Draytek router can use most of those as the backup connection, but since portability is not an issue for my home network I decided to go for a speedier cable backup.
You’ll need a Dual WAN router
Draytek 2910G Dual WAN routerDual WAN (or multi-WAN) is tech speak for a router that can juggle more than one ‘incoming’ internet connection. Most routers have a single WAN port, which you hook up to your modem. These have two or more. It may sound complicated, but it really isn’t. There are other brands that offer Dual WAN routers, but here in The Netherlands, Draytek seems to be the only consumer brand that offers this type of product.
Dual-WAN router do not come cheap (mine was around 200 euro), but since they let you use the second connection instead of paying for a line you’ll only use in cases of emergencies it seemed like a good investment to me. To cut costs a little, I went for the wireless-g model, but there’s a wireless-n one as well.
Connection 1 -- Tele2 DSL
Davolink DSL modem/routerI’m naming my ISPs in this post because there are some specific issues with some of them. Tele2’s Davolink modem/router for instance needs a little work in order to get it working with the Draytek.
Because Tele2 offers VoIP services as well, you can’t bypass the router and have it function as a modem only. In fact, they’ve disabled most of the router’s user interface, so there’s very little you can change at all. Luckily, you can set up a DMZ. Here’s how to set it up. Because both the Davolink and the Draytek offer wifi, you can simply switch wireless networks to get from on to the other. The manuals for both devices contain info on how to accomplish these steps.
1. Hook up one of the Davolink’s LAN ports to the Draytek’s WAN1 port.
2. Log into the Draytek’s web interface and set up static IP internet access for WAN1.
3. Specifiy a fixed IP address in the Davolink’s IP range (192.168.1.x by default).
4. Log into the Davolink’s web interface and set that IP as the ‘DMZ host’.
5. Set up the Draytek’s DHCP server to use a different IP range (such as 192.168.2.x).
That’s it. This will route all traffic to the Draytek, while still keeping the router active to handle VoIP.
Connection 2 -- Ziggo cable
Motorola SB5120 cable modemMy Motorola cable modem doesn’t function as a router at all. Simply connect it to the Draytek’s second WAN port, and set up internet access for WAN2 using ‘DHCP Client’ mode. Very easy indeed, although you might need to unplug your modem for a few seconds before it accepts the router. Cable modems usually assign themselves exclusively to the first network adapter they come across. Once you plug it back in, that will be the router’s WAN port.
Optional: Create load balancing rules
Dual WAN routers usually offer lots of settings for balancing your traffic over the two connections, and the Draytek is no different. I love that the default settings are to simply balance automatically based on how fast both lines are. But you can also set up rules to specify what kind of traffic goes where. I’ve created only one. It assigns torrent traffic to one WAN connection, so I still have the other one available for other stuff.