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robert_wrenn_7675097's profile
robert_wrenn_7675097
100 Points

6 Messages

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140 Points

Sun, Dec 18, 2016 11:39 PM

P300 SpeedFlex test , is it accurate?

Using a P300 bridge about a quarter of a mile apart to connect a ZoneDirector 1106 to six 7782 APs. We were expecting at least 500Mbps up to 900Mbps throughput from the P300 bridge but are only getting about 200Mbps or less using Speed Flex.
Any ideas why so slow?

Question

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Updated 

3 years ago

27

6

Responses

john_dong

Champion

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556 Messages

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10.5K Points

4 years ago

SpeedFlex unfortunately is a pretty accurate and even optimistic estimate of the maximum TCP (and UDP respectively) throughputs you can expect to see across the link.

I'm not sure that 900mbits of throughput is what I would expect.... The P300 is 2x2:2 802.11ac, so even with 80MHz channels, the max PHY rate is 867mbit/s, but actual data rate will be lower due to wifi signaling overhead as well as IP overhead, noise, and signal degradation.

But that's not to say that 200 or less is what you should expect, though. Just pointing out, the intrinsic physical limits of 802.11ac 2-stream wifi makes 900mbit not reasonable. I would say around 500-600mbit is the highest rate you would expect to see in Speedflex with a pair of P300's in the most ideal of signal conditions.

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robert_lowe_7229256

222 Messages

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3.6K Points

4 years ago

I would be surprised to see a 2nd spacial stream hit on a P-P bridge even at 1/4 mile. What channel width are you using? Presuming you have a properly aligned link and have adequate clearance of obstacles through the link?

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robert_wrenn_7675097

6 Messages

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140 Points

4 years ago

Channel with is 40. Signal is RSSl 48 and pure line of sight with no obstacles.

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robert_wrenn_7675097

6 Messages

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140 Points

4 years ago

I see you mention 80 MHZ width Channel. We were told to use 40. Is that our problem?

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john_dong

Champion

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556 Messages

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10.5K Points

80MHz channels will nearly double the max throughout and I find in practice it does close to double observed throughout. With point to point bridges I would not expect much co channel interference concerns around operating 80MHz.

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4 years ago

0

robert_wrenn_7675097

6 Messages

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140 Points

I am going to suggest we try the 80Mhz channel width. Will let you know what happens.

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4 years ago

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alan_rothenstreich

62 Messages

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936 Points

4 years ago

I am having a similar issue with a pair of P300's and currently have an open case to troubleshoot why I am not seeing the expected speeds with an 80Mhz channel.  Duplicated on my bench so shall reply if we find a root cause.

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jim_laus

1 Message

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60 Points

3 years ago

Found this thread while researching the same issue.  I know this is a year old but, wanted to comment incase anyone else came across it.  After a bit more research found this in the release notes from version 100.1.0.9.57 under "Resolved Issues":

Added a warning message informing the user that the SpeedFlex tool built into the P300 UI is unable to accurately measure the maximum throughput speed due to CPU limitations, and therefore users should use SpeedFlex to verify connectivity only, or to use an external platform to run speed testing. [FR-2706]

Hope it helps

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