Ok, I am listening. Thanks for the info ( also thanks to Ben and Erik). We will simply have to find an alternative for remote file access (or the people that do not believe me will have to beat their heads). This does confirm what I thought. Thanks.
Gene Giannamore Abide International Inc. Technical Support 561 1st Street West Sonoma,Ca.95476 (707) 935-1577 Office (707) 935-9387 Fax (707) 766-4185 Cell gene.giannam...@abideinternational.com -----Original Message----- From: Steven M. Caesare [mailto:scaes...@caesare.com] Sent: Friday, May 29, 2009 8:30 PM To: NT System Admin Issues Subject: RE: Mobile Satellite for Internet access The deal with sat service is, as mentioned, the unavoidable ~700ms delay associated with the bounce to the bird and back... Typically, mechanisms to mask that latency fall in to two categories: -TCP ack suppression: waiting for an ack after each transmit window grinds connections to a halt, even if the overall bandwidth is more than sufficient. A 8Mb sat link would be lucky to see more than a few hundred Kb actual throughput. By using the underlying satellite carrier mechanisms to determine successful transmit the system can spoof acks at the endpoints, and avoid that hit. -Intelligent proxying: Intelligently dealing with well-known protocols can also mask some of the delay. A web page load can encompass dozens, or sometimes upwards of a hundred object loads, often requiring a large number of TCP connections to various servers, with an initial TCP handshake(which typically is NOT suppressible), thus incurring significant initial delay. That sat system will proxy that request locally, batch up all the object requests, and marshal them across the link in a single connection to a back-end proxy, which will pull the objects from the interweb and then push them back in a single connection back to the client. Despite such good efforts, two things you want to do make that hard: - VPN: The TCP syn/ack sequence is now inside an encrypted tunnel the sat system cannot see, so it cannot spoof the acks. Data inside the tunnel becomes SLOOOOW.... Typical ways around this are to terminate the VPN tunnel at terrestrial each end of the sat link, and depend on the sat provider to guarantee privacy over the shot to the bird and back.... with varying degrees of success. I dunno if Mobilsat is doing that or something spiffier. - RDP: Despite the ack suppression at the packet layer, if the application layer is highly chatty/interactive then the delay still kills you. Waiting a second or more to see you terminal keystroke is painful, although local echo can make it tolerable for occasional/light use. Waiting for your mouse pointer/window drag to catch up in your RDP session is similarly ugly. If your only alternative is a 14 hour plane trip, it's workable, otherwise sat is great for multicast/specialized traffic, but tends to suck as a broadband ISP alternative. -sc -----Original Message----- From: Gene Giannamore [mailto:gene.giannam...@abideinternational.com] Sent: Friday, May 29, 2009 7:58 PM To: NT System Admin Issues Subject: RE: Mobile Satellite for Internet access What about the VOIP offerings that some sat isps offer? One company offers "CIR is $5/per Kbps", so an extra $150 per month for 30Kbps? I wonder if that would work for RDP. Or maybe something like this http://www.mobilsat.com/satellite-VPNVirtualprivatenetworking/ could be used? I need to call them and find out. Or maybe we need to move away from Terminal Server and go with something else. I am liking the idea of peersync for data files, and a web based application for our main app. Gene Giannamore Abide International Inc. Technical Support 561 1st Street West Sonoma,Ca.95476 (707) 935-1577 Office (707) 935-9387 Fax (707) 766-4185 Cell gene.giannam...@abideinternational.com www.abideinternational.com -----Original Message----- From: Steven M. Caesare [mailto:scaes...@caesare.com] Sent: Friday, May 29, 2009 4:34 PM To: NT System Admin Issues Subject: RE: Mobile Satellite for Internet access +1. Sat is evil for chatty protocols... which RDP is the epitome of. -sc <-- former sat ISP tech weenie as well -----Original Message----- From: Erik Goldoff [mailto:egold...@gmail.com] Sent: Friday, May 29, 2009 6:22 PM To: NT System Admin Issues Subject: RE: Mobile Satellite for Internet access You could use a portable sat like truckers have for internet access, BUT ... You're NOT gonna like RDP over VSAT. VSAT is high latency, minimum 600ms or more as you have to roundtrip 100,000 miles to see the result of a keypress ( sync satellites are 23,000 to 26,000 miles up in orbit ) I used to work for a retail operation with VSAT, and we ended up putting in DSL also for Terminal Server access to payroll applications as they were simply painful to use over satellite. Do you have any cell coverage at all at the site ? Better off with EVDO or even connection to cellphone as a modem Erik Goldoff IT Consultant Systems, Networks, & Security -----Original Message----- From: Gene Giannamore [mailto:gene.giannam...@abideinternational.com] Sent: Friday, May 29, 2009 6:01 PM To: NT System Admin Issues Subject: Mobile Satellite for Internet access We have a need for a semi-mobile satellite setup at a remote construction site. Basically because of theft, we need to lock up the equipment at night (even then it might get stolen). So we hope we can find some equipment we can setup each day for internet access, mainly to access our terminal server via RDP. Maybe put it on a cart along with a wireless router, or plug the Ethernet cable into the trailer (if we can wire the trailer). I have found several companies that provide this service. Wondering about people's experience with this. Thx. Gene Giannamore Abide International Inc. 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