Tuesday, December 01, 2009

Comcast Cranks Up DOCSIS 3.0

A month ago Comcast upgraded my head-end for DOCSIS 3.0.  I had some backwards compatibility problems so Comcast gave me a new DOCSIS 3.0 cable modem.  My problems went away and my bandwidth increased dramatically.

I must say that I am getting quite use to the extra bandwidth.  Windows 7 download in only a few minutes, and I enjoy the quicker upload speeds for posting pictures and blog posts.  The 3 Mbit/s upload is pretty consistent in my neighborhood.  The only time I wish I had more upstream bandwidth is when I am moving large PowerPoint files or synchronizing to the cloud. 

Having this much bandwidth exposes two deficiencies.  The first deficiency is that my home network can now be a bottleneck.  I have one 10 Mbit/s device, 2-100 Mbit/s device, a 1 GigE device with a 802.11g/n network.  My machine-to-machine transfer rate tops out at 20 Mbit/s.  The second deficiency is latency. It takes 27 ms to go round-trip to local Comcast servers.  The latency to some of the SBC approaches 100 ms which introduces echo into my VoIP calls. 

I can fix the first problem by buying a new Ethernet swtich and more GigE devices.  After all it is only money.  The second problem is not something that I can fix because after all this is a best-effort service. 

I am delighted that all of the computers and game consoles in the house has enough bandwidth to do what they want, but our phone calls still suffer from echo.  I would really like to see Comcast offer different classes of service for their High Speed Internet.