Wildblue, general satellite latency, errors in previous post

Posts: 1 · New Forum Member Joined: Jun 19, 2007 Posts: 1

Hello. I just joined after reading several Wildblue (and other) satellite related posts. I noted several erros and mis-information, so I'm going to offer some corrections and observations:

1. The slowest WB account averages out to a download of 250mb per day, NOT 333.

2. Latency and 'spot'beams' ARE NOT related. A spot-beam merely concentrates a signal to a specific area. It doesn't change the laws of physics.

3. WB tends to exhibit less latency than other satellite systems because of newer technology, NOT because WB runs on Ka band. Again, the laws of physics apply - miles are miles - no way around it at present.

In general, WB exhibits less latency than other satellite providers. Why? Because of newer technology and a better method of processing TCP/IP data on the satellite as well as at the ground stations. DirectWay, Hughes, etc., all use TCP/IP encapsulation. Placing a packet into a 'capsule' equals CPU time to do it, and CPU time to un-do it. WB doesn't encapsulate.

Roundtrip latency isn't just mileage to/from the satellite. It is just as much about the computers at each ground station, as well as the speed of the computer on-board the satellite. Everytime a packet has to pass through a computer, there's processing time. If the packet is encapsulated, that processing time increases.

The older systems, like Hughes, DirectWay, DirectPC, etc., use a fixed transmit and receive power. WB uses a dynamic approach: There are basically 3 power levels avaiilable. Depending on weather, dish alignment, etc., the system will step to whatever power is needed to maintain performance. The user never sees this happen.

While power has absolutely nothing to do with latency, is is a MAJOR factor where packet loss is concerned. In pure TCP/IP, lost packets are re-sent. Then the receiving end must take that 'late' packet and insert it into the proper slot in order to complete a download - a received "message" if you will... That takes time. And if you have a slow PC, you WILL notice it.

If we can adjust power to minimize packet loss and retransmission, our overall performance improves. Even though the assigned data rate is unchanged, the end-to-end packet throughput is improved. That is the basic strategy employed by WB.

It isn't unusual to see the older systems have a latency of greater than one second. As per above, much of this IS NOT mileage. It is processing, retransmitting, etc.

The older systems are marginal, at best, for Vonage (or ANY VOIP). WB does somewhat better, but it is still far less 'transparent' than what you would experience via landline.

Another item is how VOIP behaves compared to standard TCP/IP. VOIP, in general, doesn't retransmit lost packets. It just discards them. That's where you hear the choppiness, etc., in voice calls. So, again, if you can minimize packet loss, you minimize "chop"...

I've been installing sat. systems for 28 years now. I've installed DirectWay, Hugues, DirectPC, StarBand and Wildblue. Got a pretty good idea of how all this stuff works!!!

Licensed ham, hold an FCC Commercial license with RADAR, and graduated U. of Md. (BSEE) in 1980. Active WISP as well.

Will be happy to try to answer specific questions that are addressed to "wb7cjq@4wbi.com"

Dave.

Posts: 19 · Vonage Forum Associate Joined: Aug 10, 2005 Posts: 19

The problem with WildBlue is if they notice VoIP activity they can and will cancel your account. They may not go that far anymore, but they will block the VoIP ports. They do not allow VoIP at all. We have fought long and hard with them regarding this. They just do not allow it.

Posts: 1 · New Forum Member Joined: Oct 28, 2007 Posts: 1

That is odd I have had wildblue for over a year and use netzerovoice with no trouble. The problem is they just informed me they will no longer be providing service and I need to find another voip that supports satellite. I do a live internet radio show with it and WB has never shut anything down.

Sounds like vonage is not for me for many reasons.