Author Topic: Configuration Optimisation  (Read 3904 times)

G4IRN

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Configuration Optimisation
« on: 2014-01-03, 11:09:17 »

Apologies if this has already appeared on the forum but I couldn't find anything relating to it.

My question:  For a set of given network characteristics, can the optimum RRC configuration settings be determined?

Over recent days I've been playing with a pair of RRC-1258 MkII units connected to my home-based K3. I've connected in remotely via internet and 3G mobile phone, in both cases playing with the jitter buffer, jitter delay, audio packet size and audio quality parameters to ascertain the best settings that work for me. Whilst many combinations of settings work OK, I'm left wondering if I have the optimum values set at any particular time.

Maybe I'm completely wrong here, but it strikes me that for any given values of connection parameters (speed, latency, bandwidth and their deviations - any more?) there should be a set of optimum RRC settings. Am I correct in this assumption? If so, then there should surely be an algorithm to work out the optimum settings? Maybe I'm being too simplistic.

Another point I note is that there is no definition of  'jitter' - I am not sure if this is a description of the cause, or of the effect, however my assumption is that the cause is the variation of values that can occur in speed, latency and band-with.  Correct? In setting the configuration values, do we need to address the 'average value' of these parameters, or the 'worst case'.

That then brings me to the question of how these connection parameters can be easily measured. From my limited knowledge of these things, I (again) assume the following:

* Connection speed (up/down) can be measured using an internet speed check, e.g. http://www.speedtest.net/.
* Latency can be measured using a PING instruction to measure the delay on a given connection.
* Band-width - I'm guessing that this is related to speed.
* For all the above, tests over time will show any variations in these values (which I assume to be/cause 'jitter').

Hopefully someone can set my mind at rest here!

Thanks.
John G4IRN.

oz1rh

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Re: Configuration Optimisation
« Reply #1 on: 2014-01-09, 00:33:59 »
In the context of computer networks, jitter is the variation in latency as measured in the variability over time of the packet latency across a network, see http://en.wikipedia.org/wiki/Jitter

Tools to check your connection:
http://www.pingplotter.com/
http://www.pingtest.net/
http://www.ringcentral.com/support/qos.html
http://www.internetfrog.com/myinternet/voip/
http://www.speedtest.net
There are many more, Google is your friend. Search for "VOIP Quality" or just "jitter".

I mostly use pingplotter and www.pingtest.net Pingtime/latency and jitter are more important than speed, a few hundred kbit/sec should do. The RemoteRig manual describes how much (or how little) speed is needed. I have no algorithm to work out the optimum settings other than reading the manual and this forum.

73, Palle, OZ1RH.
« Last Edit: 2014-01-09, 12:15:06 by oz1rh »

sm3ccm

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Re: Configuration Optimisation
« Reply #2 on: 2014-01-12, 11:40:56 »
Palle.
Thanks for the tool list.
I would like to add:  http://www.host-tracker.com  to the list.
73 de Lars SM0CCM

oz1rh

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Re: Configuration Optimisation
« Reply #3 on: 2014-01-14, 23:07:31 »
Tnx Lars,

When everything works it is a good idea to use www.host-tracker.com to monitor connection to the remote site. At work I used Xymon http://xymon.sourceforge.net/ for more detailed monitoring of servers and websites.

I use my Android phone with Overlook Whiz from Google Play/Android Market for monitoring access to the webpage of my radio RR. See https://play.google.com/store/apps/details?id=com.overlook.android.whiz&hl=en

73, Palle, OZ1RH.