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Verizon Wireless' network optimization
Feb. 13th, 2011 11:43 amSome of you may of heard of Verizon Wireless doing some network optimization techniques that are... questionable. They've detailed the efforts at http://support.vzw.com/terms/network_optimization.html.
In essence, they're transparently proxying web traffic on their wireless IP network, and trying to squeeze more stuff over the air with how they've tuned their network. They'll compress or re-compress the content.
Of course, I have objections.
Plain text and HTML formats I have no objections with. It's basically doing an in-line HTTP-supported GZIP compression which most browsers support.
Image and video re-compression I have objections.
The idea is that most people won't watch all of a video when browsing. So Verizon sucks down all the video, and buffers it into a progressive download at a speed that's slightly better than what is being decoded and viewed. If you stop and switch out, Verizon times out and stops sending video mid-stream. This means you get Just-In-Time video delivery... or in essence, you're watching Youtube like it was Justin.TV, UStream or Livestream.
Of course, there's three ways around it. First is to use HTTPS. Second is to use a different port. Third... is to stay on AT&T Wireless for iPhone usage.
In essence, they're transparently proxying web traffic on their wireless IP network, and trying to squeeze more stuff over the air with how they've tuned their network. They'll compress or re-compress the content.
Of course, I have objections.
Plain text and HTML formats I have no objections with. It's basically doing an in-line HTTP-supported GZIP compression which most browsers support.
Image and video re-compression I have objections.
- Lossless GIF/PNG/TIFF re-encoding sounds like it'll get converted to JPEG. That doesn't work, when you want a high-resolution PNG/TIFF and want it to be perfect. What if you're pulling a file from a public source to edit on, and have ARTIFACTS?!? "But it won't be noticable" they say. I'll notice them when I'm editing a PNG that's really a JPEG!
Now, if they run the GIF/PNG/TIFF though a lossless optimization, shrinking the file from 24-bit to indexed, or even using Optipng/pngcrush, I'd see no problems with it. - Lossy JPEG re-encoding will only make it worse, and noticable. JPEG already tosses out information, and most are set to be fairly good. Recompressing it makes it worse.
- Video gets transcoded to H.264 when the server sends a different-coded file and the client can accept H.264. They'll try to keep things the same, but with transcoding, it'll get worse. I've re-encoded MPEG4 and DivX to H.264. I've had to push the bitrate up to 4Mbit/s to get an acceptible picture.
For an iPhone over the cell network, think of the 240p videos you get from Youtube, but with worse quality.
The idea is that most people won't watch all of a video when browsing. So Verizon sucks down all the video, and buffers it into a progressive download at a speed that's slightly better than what is being decoded and viewed. If you stop and switch out, Verizon times out and stops sending video mid-stream. This means you get Just-In-Time video delivery... or in essence, you're watching Youtube like it was Justin.TV, UStream or Livestream.
Of course, there's three ways around it. First is to use HTTPS. Second is to use a different port. Third... is to stay on AT&T Wireless for iPhone usage.
