Wireless Ping Times vs Distance
Last Post: August 3, 2006:
I have a question.
Is there some reference point where I can get some basic theory about how wireless ping time would/could/should vary over distance.
For example: If I ping a bridge radio in my network that is .9 miles away and I get some min, max and avg ping numbers. Then if I were to ping a bridge radio in my network that is 8.5 miles away and I get some min, max and avg ping numbers.
What I am curious about is the impact of distance on the performance of the network when I start to add clients to this leg of the network?
Any thoughts or discussion would be more than welcomed.
I have not seen the same benchmarking for this as exist on bounded networks. There are too many things in the mix, (interference, weather, multipath, RSSI, etc.) What I have seen is baselines and comparrisons to the baselines combined with a throughput test. In a perfect world RF travels at a given speed which could be used with the distance and frequency to come up with a rough idea. However, the media we use, the air, is not as easily controled and measured as the bounded networks cables. A basic answer would be that you should observe longer PING response times at greater distances much like on a bounded network. An exact measurement could be taken but may vary from location to location based on environmental factors.
You won't see much of a distance in ping times. If you do the math you can come up with how long it would take for the signal to get there. Here is the math:
Your 8.5 mile link is 13685 meters. RF travels at 300,000,000 meters per second. The calculator says that is 4.56166667 ???¡ª 10-5. Um, that is really, really fast. I can say from experience that you will not see latency at any distance that is normally seen in an outdoor 802.11 network.
Ping times are an inconsistent way to analyze network speeds (in any network) because ping packets are always given the lowest priority.
You should use the connection analysis tools that should be included with the bridges. That will give you a much more consistent view of what's going on between the bridges than anything else.