nanog mailing list archives

Re: Satellite IP


From: Lamar Owen <lowen () pari edu>
Date: Mon, 10 Jan 2011 14:37:53 -0500

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.


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