Time Warner Cable: 2.8Mbit Upstream

Hey- Apparently Time Warner Cable doesn’t rate-limit UDP packets (as far as I can tell).

 

Here is the scenario:

Time Warner Turbo (15Mbit down / 1Mbit up) connected to OpenVPN (10mbit limit) at a local data center.

 

Here is what the connection path looks like:

Time Warner Cable –> OpenVPN –> Squid Proxy –> Website

 

At first I didn’t know what to think – I can normally achieve around 1Mbps up but I was getting over 2.8Mbit/sec upstream! I thought to myself “This has to be Squid caching the upload test data” so I altered the Squid configuration to explicitly NOT cache the data from SpeakEasy’s test site.

 

Here’s what I found:

 

Before
image
After (10Mbit limited by OpenVPN)
image

 

How can this be? Well it might have to do with the fact that Time Warner doesn’t monitor UDP traffic (at least to OpenVPN UDP 1194). After reading many documents, it’s evident that traffic shaping TCP is easy and TCP comes with traffic shaping mechanisms and UDP does not. My speculation is that Time Warner simply drops packets when rates are too high, causing TCP to (inherently) re-send data that is lost.

 

Quick HowTo

The first thing you should do is grab a copy of Untangle. It’s quick and easy to set up OpenVPN out of the box.

  1. Obtain OpenVPN
  2. Bring OpenVPN online at a Data Center or as a VM on your leased server at a Data Center.
  3. Connect to OpenVPN from your Time Warner connection.
  4. Start a VM with Squid caching proxy running. Make sure that you have access to this VM from your VPN client (configured in Untangle)
  5. Start Squid
  6. Open your favorite browser and point it to the squid proxy (private IP address via OpenVPN)
  7. Access speed test sites (all OpenVPN traffic is UDP so you should be able to achieve speeds without using Squid)

Comments

  1. Awesome article, can’t wait to try it out!

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