On Mon, 10 Jan 2011 11:06:32 EST, Kelly Olsen said:
That would only happen with an outrageously over-subscribed provider.
OK - I'll feed the troll. What's the proper amount of unused and therefor non-revenue-generating capacity the operator is supposed to reserve in order to *guarantee* that bandwidth will be available? (Hint - the provider doesn't have to be "outrageously" oversubscribed - by definition, if you're oversubscribed *at all*, it's possible for somebody to lose out. It's easy for the provider to be 98% sure that they'll be able to satisfy all the requests. But guaranteeing 100% is a whole nother story...)
----- Original Message -----
From: "Valdis Kletnieks" <Valdis.Kletnieks@vt.edu>
On Mon, 10 Jan 2011 11:06:32 EST, Kelly Olsen said:
That would only happen with an outrageously over-subscribed provider.
OK - I'll feed the troll. What's the proper amount of unused and therefor non-revenue-generating capacity the operator is supposed to reserve in order to *guarantee* that bandwidth will be available?
(Hint - the provider doesn't have to be "outrageously" oversubscribed - by definition, if you're oversubscribed *at all*, it's possible for somebody to lose out. It's easy for the provider to be 98% sure that they'll be able to satisfy all the requests. But guaranteeing 100% is a whole nother story...)
Ok, I'll feed the troll. :-) Those who want to *guarantee* that they will never lose out -- people like network news organizations -- *lease entire transponders by the year, or for the projected lifetime of the satellite*, after which those 36MHz are yours to do with as you like; here's a list of the current *dedicated* ABC transponder avails: http://www.abcnewsabsat.com/files/frequencies_nac_041510%5B2%5D.pdf There's really a *lot* of space-segment available, Valdis. A lot. And if you buy a transponder for the entire projected 15-year lifetime of the bird, I hear you get a pretty hefty discount over the hourly rack rate. ;-) Now, in my particular case, the secondary usage I was talking about wasn't so much first-line municipal support per se, but backup to that, in the way that hams have always provided that sort of support, just fancier; in that case, it's practical for me to utilize contended, and therefore substantially cheaper, occasional time (LBiSat, for example, has quoted me $179/hr for 3MHz, and $250/hr for 4.5MHz as a rack rate, which is acceptable for my primary use, as long as the uncontended-service packet-loss and jitter numbers are low enough; contended time should be much cheaper than that), and in either use case, since there are at least 3 providers, with a total of something like 12 full transponders, who provide occasional iDirect connectivity, I shouldbe able to book the time *somewhere*, just as "traditional" DSNG operators (using DVB-S MPEG2, mostly) always have. Thanks to Kelly, I'd seen Skycasters, but didn't get the impression from the website that they did anything other than monthly service; to James, I'll check out Trustcomm; and to Ryan: yeah, there are Video-to-MPEG-to- IP-Ethernet encoders off the rack; for that use-case, I mostly need to find a matched pair that's efficient; the primary use of the truck will *not* be sports. :-) And I'll be leaving in the DVB-S modulator that's there, so if the truck is suitable to someone for rental, they'll be able to use it in the traditional fashion as well. My motivation for asking the question *here* was of course to get the operator perspective on the actual transport, if anyone had any. Cheers, -- jra
On Monday, January 10, 2011 01:28:07 pm Jay Ashworth wrote:
My motivation for asking the question *here* was of course to get the operator perspective on the actual transport, if anyone had any.
I helped a radio station put together a remote trailer using a mobile satellite system back in 2004; SDN was the provider. Bandwidth we had available was I believe 1.5MB down and 384K up, burstable to 512K IIRC. Mobile satellite operations is a trip, especially with the 4 watt uplink transmitter required at the time for the wide uplink bandwidth. For the target use, UDP video and audio streaming, it worked very well once the system linked up; satellite acquisition and clearance for uplink transmitter RF turnon was typically a half an hour or so. When using TCP, however, the latency was noticeable. Once the stream started and slow-start finished the bandwidth was what you'd expect from a terrestrial circuit, but slow-start was really slow, thanks to the propagation time to and from geosync orbit. These systems had great use for VoIP PBX trunks for setting up a field phone system; the IP phone 'extensions' connected with WiFi, and the PBX itself was in the trailer, with the PBX to outside trunks handled by the satellite link. The system was decommissioned just this past year due to the uplink bandwidth cost, the intermittent system use, and the penetration of G3 data services in the area.
participants (3)
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Jay Ashworth -
Lamar Owen -
Valdis.Kletnieks＠vt.edu