posting data and latency issue
Posted: Fri Feb 29, 2008 2:49 am
by SmokyBarnable
Ever since I started accessing the internet via a Starband satellite system I have been having problems with the administration portion of my oscommerce site. I encounter problems when I try to add a new product, for example, and fill in a bunch of forms. After filling in the forms and clicking update or insert it works only about 20% of the time. When it doesn't work it immediately goes to a "Internet Explorer cannot display the webpage" page and the database query is not performed. I'm wondering if the inherent latency issue with satellite internet technology is causing the problem. Is there anything I can do to solve this problem?
It just did it again when I tried to post this question....about 20 times.
Re: posting data and latency issue
Posted: Fri Feb 29, 2008 10:03 am
by Christopher
Sounds like the browser think it has lost the connection to the Internet. Is there a setting for your browser to increase the timeout?
Re: posting data and latency issue
Posted: Mon Apr 14, 2008 4:03 pm
by supermike
I have the answer for you, as a former network sysop at a company that knows a good bit about how these satellite Internet connections work.
You see, with the Internet, there is TCP and IP, as you may have heard. However, they don't really call it IP at the socket communication layer, but UDP. TCP, you see, works like a phonecall -- you pick up the phone, dial a number, and your wire is switched over to that call for as long as you both stay on the line. It's called a connection-oriented connection. Now UDP, however, is like an email -- you write the email, and it goes off and the guy might get the answer in a few minutes or so. This is a connection-less connection, as they say.
Okay, so when you do HTTP in your browser, you are using the TCP protocol. But guess what? Satellites can't talk TCP purely. So, your router, the router in the satellite, and the router back down on Earth at network control -- they all do a busy thing where they take your TCP, wrap it up into UDP, and send it up and back on to its destination again. TCP works fairly well doing this most of the time if your satellite is tuned properly and it's a clear day, or sometimes even in unclear days. The trouble, however, is when you start doing HTTPS or VPN connections. This is because instead of TCP being a normal size, it's like mega big. This means that the UDP is going to be stretched to about its limit in what it can handle. It will work for a few minutes, but as soon as you start doing something heavy-duty, it will timeout on you. Part of the problem is also that the NOC (Network Operations Center) has all these HTTPS connections coming in where people are doing the same thing you're doing, and the routers there get overwhelmed with all these ginormous packets that have to be reassembled in the right order, then the TCP pulled out, and then TCP is sent on the wire.
In the fine print of all satellite providers and their rules, they will tell you that VPN is supported on a best-effort basis. And if you call up their tech support, they will finally admit on the phone that HTTPS will timeout in some very large transactions.
To make matters worse, there's something else you should know. If a bird lands on your satellite dish and knocks your tracking off, it's fairly easy with DISH Network to listen to that tone thing in you TV in the menus and re-establish the strong signal. However, the bad news is that you can't do this for the feed horn for the Internet connection on that dish -- not without specialized expensive equipment. So, you call your provider out, and if you're lucky he has this equipment. In my case, he merely used the TV thing to judge and that turned out to not be good enough. When I called Starband up, they said they would send a tech out with the proper equipment, but it would cost me $200 and I would have a two-month waiting list.
In a nutshell, satellite Internet blows when you need to rely on it, and especially if you're a developer.
So that of course leaves you with DSL and cable modems, which probably aren't an option for you. One option is WiMAX, but few people have that yet. Another option is to horn in on your neighbor's wireless using a cantenna and some boosting equipment, but in some states you can get busted for that if caught. So that leaves a couple options still available to you.
For one, I used a device called a Maxstream Express Ethernet Bridge. The kit costs $700. This kit is amazing. I have a sister-in-law that can't get high-speed Internet. So, she bought this kit with my advice. We plugged one wireless end up in my house, and another in hers, and there's like 1.5 mile between us and dense woods. In my house, I put my unit up high (upper floor) in order to increase the range. Within about 2 minutes, the signal is established, is very strong, and she gets on my Internet just as if she was here in my house. The signal goes right through walls and woods just like cutting butter. In fact, I did a test with it and I could get a weak signal at 3 miles, and a fairly strong signal at 2 miles, without clear line of sight.
Another approach is to get some radio hobby guys in town to help you build a satellite dish that points at the closest McDonald's restaurant in town. Most McDonald's come with free wireless Internet. However, there are other wireless businesses in town. You could be like 10 miles away and with a tower and a dish and some radio hobby guys, you just might be able to eek out a 900K signal, which is all you really need, minimum, in order to be reasonable. And although this takes TCP and encodes it in a UDP-like wireless protocol, it does work more reliably than a satellite dish.