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Message started by Kiran on Jul 16th, 2016 at 11:25am

Title: Satellite Network latency chart for a WAN Emulator
Post by Kiran on Jul 16th, 2016 at 11:25am
Hi Guys,

I am working on an open-source WAN Emulator called TOFFEE-Mocha. Along with other WAN Emulation features you can configure packet latency in milliseconds and microseconds in the same.

But to emulate satellite networks I need a chart consisting Satellite Network technologies (standards/specs) and the corresponding latency in some form of chart.

If case if you guys have the satellite networks latency chart can you please forward me the same?

Besides if you are looking for any new features specific to satellite networks can you suggest me the same. Here is my project URL: http://www.the-toffee-project.org/

Title: Re: Satellite Network latency chart for a WAN Emulator
Post by Admin1 on Jul 16th, 2016 at 7:00pm
Not sure what a latency chart would look like?

Transmission delay occurs in satellite communications simply due to the distances involved.

Geostationary satellites have a single hop, up + down delay of 240 - 280 mS, depending on the locations of the earth stations.  On the equator and looking straight up you get the shortest distance and minimum latency.

Best regards, Eric.

Title: Re: Satellite Network latency chart for a WAN Emulator
Post by Oasis Networks on Jul 16th, 2016 at 8:24pm
Hi,

Please dont forget other factors contributing to the latency, such as buffer size and FEC block size (which varies as well according to the data rate). Also spoofing and other packet related processing should contribute to the latency.

Nimrod

Title: Re: Satellite Network latency chart for a WAN Emulator
Post by Kiran on Jul 18th, 2016 at 8:11am
Thanks a lot guys. Let me work out with those values provided.

Title: Re: Satellite Network latency: O3b MEO network
Post by Admin1 on Jul 18th, 2016 at 10:39am
A novel medium height satellite network has become operational in the last few years, called O3b. 

O3b is an operating constellation of 12 satellites, spaced at 40 deg intervals along a single medium height orbit directly above the equator. The height is 8062km and this results in lower latency compared with geostationary.  This is a key selling point. If a typical single hop path involves two sloping path lengths of 11000km the single hop distance is 22000km with a latency of  73 mS. O3b claim a "round trip" latency of better then 150mS. Their 150 mS "round trip" definition refers to a double hop distance of 11250 + 11250 + 11250 + 11250 km.

Speculative future low earth orbit (LEO) satellite networks with constellations of hundreds of satellite may operate with lower orbit heights like 1200 km.

The speed of radio waves is 300,000 km per second.

Read more about satellite latency and O3b orbit

Title: Re: Satellite Network latency chart for a WAN Emulator
Post by Admin1 on Jul 21st, 2016 at 9:29am
Another cause for latency is network firewalls. You need to make sure they have enough RAM for the traffic flow. If the firewall runs out of memory and starts caching to disk it delays packets.

Best regards, Eric.

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