Clear WiMax: Bandwidth Throttling Now In-Place?

A few months ago, I decided to try out Clear Wireless WiMax as they offer ‘unlimited’ 6Mbs down over WiMax (refer to Clear WiMax in Atlanta, Clear WiMax Intial Review, and Clear WiMax Follow-up). However, after a few weeks, I started receiving notices that I was using too much bandwidth (see Clear ‘Unlimited’ Plans and Clear Usage Addendum).

More recently these warning letters have ceased with no explanation.

A few notes about WiMax; it is a very moody connection: often I can get speeds of up to 8Mbps, but other times I am stuck at around 2Mbps (rotating the router an inch or so left/right usually resolves this). During a rainstorm, my speed tops out at about 3Mbps, but with a wide range of variance (4Mbs down to 500kbps). The result of this bandwidth ‘feature’ it is very often hard to figure out what the heck is going on.

Today I tweaked with my bandwidth monitor (NetLimiter) to try to see if there are any traffic shaping/throttling patterns.

  • One obvious pattern is that if I use my full bandwidth for 10 minutes, by speed drops to 1Mbps (about 125kB/sec). If I disconnect for about 15 minutes and reconnect, the bandwidth returns to full speed.
  • If I run full speed for 9 minutes, cap my downloads to 1Mbps for 9 minutes and then go back to full speed, I will top out at about 1.9Mbps and 10 minutes later it drops to 1Mbps.
  • When I set my download limit to about 3.6Mbps (450kB/sec), I do not see any throttling after 25 minutes at this speed.
  • After about 9pm at night, there does not appear to be any bandwidth throttling

It could be my imagination or it could be an incredible coincidence, but I believe that Clear Wireless is doing bandwidth throttling in the Atlanta, GA area. While I am not overly concerned as I am using WiMax as a secondary connection, it would be very nice to know the stipulations of this traffic shaping if this actually being enforced!

Update: It also appears that this is only being used during peak hours- and the 'peak hours' are not always the same. Yesterday (Sunday), there did not appear to be a cap in place until around 5pm. This limited me to 1Mbps if I used any amount of bandwidth for over 10 minutes. It ended around 11:00pm. Perhaps this is an automated system that starts limiting connections when a WiMax tower is being saturated?

Update 2: Pretty much the same as before; bandwidth caps occur between 5pm to 11pm and not on Sunday- but I noticed that the caps are at different levels on different occasions; sometimes 1Mbps, others 2Mbps, etc. This does appear to be some sort of 'auto throtting' that kicks in- perhaps when the WiMax tower is saturated?

Another interesting note is that rebooting the modem usually clears the limit (until the 10 minute timeout expires); so I would guess the cap is per session and not per device (and rebooting establishes a new session)?


  1. I have clear out here in LV, and it is kinda iffy...however, I think right before Christmas, they fixed something, now I'm getting the fullpotential of clear......so hmm..

  2. With both the modem at home and USB modem, download speed will run around 2 Mbps. I call support and they tell me to reboot/restart everything (which I did before checking the speed), then magically my speed is around 6 Mbps. No one will tell me what they did. No one asks about web activity or possible heavy bandwidth usage.

    If the speed is high and I watch TV episodes from hulu or abc/nbc/cbs/fox, the speed will drop after an hour-and-a-half and stay low until I call support *again*. Time of day makes no difference.

    The kiosk workers don't have any information, either.

  3. About a month ago, Clear brought in a third party company to update all of the "post launch" markets. The grapevine says, "Clear invested a couple million into local tech teams to update towers." The nice thing about Clear's equipment, is the fact that it's ready for upgrades at any time. However, I still think the updates took way too long, and customers deserve higher speeds. I have still to find out an exact answer of why the speeds are not consistent. Gaming is definately out until more servers are up.