The blog of Ross Armer

Some guys have fast cars others fast computers, me… I have fast internet. Lately I had the oppertunity to add a second modem to my network to try and increase my speed beyond what my ISP offers on a single connection. Here is what I’ve learned over the past couple of days of dual-wan action.

My setup is a DOCSIS 3.0 modem capped at ~ 36 Mbps down / 2 Mbps up, a DOCSIS 2.0 modem at ~ 16 Mbps down / 1.5 Mbps up, and a fancy Cisco router to do the dual-wan load balancing.

Pros:

• You can get close to the combined total bandwidth with load balancing.  For me this is 52 Mbps down / 3.15 Mbps up confirmed sustained.
• Failover if one of the connections goes down.
• More bandwidth for downloading multiple things on multiple devices at once.
• Great for BitTorrent as it is not limited by the speed of the single connection back to you from a server.

Cons:

• You’re using two different WAN IPs and the websites / services you’re using have to be able to handle sending information back to you on these two different IPs.
• You need to bind YouTube’s video IPs to a single WAN as you will get “Sorry, this video is no longer available” errors on embedded videos half the time.  (74.125.0.0/16)
• Some browsers (Google Chrome) do not seem to take advantage of both streams.  This must be a limitation at the Application Layer as Safari, Firefox, and IE 8 all take advantage and use the combined bandwidth.
• At these speeds you’re connection is faster than most servers are able to give the information to you.  Just because you can download at 50 Mbps don’t expect to actually transfer at that speed even half the time.

I will update as I spend more time with this setup…