On Mon, 18 Feb 2002, Paul Lussier wrote: > Does anyone have satellite access out there? If so, what do you think > about it?
We have a client who signed up with StarBand's two-way satellite Internet service. It generally works, with one major problem: The latency is HORRID. Time to ping the next hop is around 700 or 800 ms. RTT to arbitrary hosts on the Internet is measured in seconds -- I've seen RTTs as high as seven seconds! The problem is one of distance. Say you want to ping your next door neighbor. On landline, your packet might go to your ISP, to their ISP, to a PoP in Boston, maybe to a peering point in New York City, and back down another route to your neighbor's ISP. All in all, between 500 and 2000 miles of copper, worst-case. Geosynchronous orbit is roughly 22,000 miles straight up. Your request has to go 22,000 miles into space, turn around and go 22,000 miles to the ISP's ground-station, travel on the Internet, get processed, return to the ground-station, travel 22,000 miles up, and then 22,000 miles back down to you, for a grand total of almost 100,000 miles. Just to ping. We don't normally think of TCP as an interactive application. Believe me, when you've got latency like that, it is. Web browsing is agonizing. Forget anything like Telnet, SSH, IRC, VoIP, etc. Our client hates it. Unfortunately, they locked themselves into a one-year contract. (They did all this without asking us, of course.) Also, the service is very heavily centered around MS-Windows, and they do some goofy things with routing (like hand out default routes which are unreachable without manual routing table updates). -- Ben Scott <[EMAIL PROTECTED]> | The opinions expressed in this message are those of the author and do not | | necessarily represent the views or policy of any other person, entity or | | organization. All information is provided without warranty of any kind. | ***************************************************************** To unsubscribe from this list, send mail to [EMAIL PROTECTED] with the text 'unsubscribe gnhlug' in the message body. *****************************************************************
