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5GHz Roaming experiments with AP903/AP802

  • hornbyp
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09 Dec 2020 00:55 #1 by hornbyp
Test Rig was as per Mesh overhead tests.

AP903 2nd floor, at one end of house.
AP802 5m diagonally below on 1st floor (disabled for Test 1 & 2).

All tests 5GHz only. 80MHz channel width (except as enforced by Mesh mode).

Test #1

AP903 in AP mode. All Roaming assistance OFF.

Neither Samsung TAB-S nor Huawei Mate 20 Pro would disconnect till signal reached -87dBm or. They appeared to cling on as long as possible!

In bottom corner of house - two floors down and some 14m diagonal distance from AP903, Mate 20 was on brink of disconnecting.
Before it did, 'FAST' Speedtest still said 16Mbps (to Internet). Continuous pings to 8.8.8.8 were erratic. Once it finally disconnected, it did not want to reconnect without manual intervention.
The TAB-S didn't disconnect and 'FAST' said 31Mbps (fast enough for 4K netflix!). It reported -75dBm in same location, but AP903 measured it as -85dBm.

Test #2

AP903 (still in AP mode) now set to "Strictly Minimum RSSI" = -62dBm. AP appeared to implement this well - ejecting station and adding to a
a block list for 15 Secs. (After 15S, with no other alternative, the client simply reconnected. Rinse and Repeat!)

(The TAB-S 'knew about' a distant SSID for my IOT LAN and connected to that - it was then kicked off there and just oscillated between the two APs! :roll: )

Test #3

AP903 Mesh Root with AP802 Mesh Node. Fully Wireless Mesh between nodes

AP903 <
5M--->AP802<---- ?
> user.

No evidence of coordination between APs with Roaming Assist OFF. Clients just showed random 'personal' preferences, as per Test #1. So there appears to be nothing 'intrinsic' within Mesh Mode that handles Roaming.

However, with "Minimum RSSI" Roaming Assist ON, normal wired-type Syslog messages started to appear and full-blown coordinated roaming occurred!!

This contradicts Draytek's documentation that says it applies to Wired-mode only. I can only assume their documentation is out of date - and they mean that it doesn't apply to WDS and Repeater modes?

One thing worth saying, is that any hope of repeatable signal strength measurements, or locations in the house where roaming was triggered, was abandoned very early on in the tests. This is definitely an Art, not a Science!

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09 Dec 2020 08:54 #2 by piste basher
Replied by piste basher on topic Re: 5GHz Roaming experiments with AP903/AP802
I salute your indefatigability, as someone once said :lol:

A quick question - did you have either or both of the "Fast Roaming" options turned on at any time? i.e "Fast Transition Roaming" and/or "Fast Roaming(WPA2 Enterprise)"

second quick question - by "full blown roaming" do you mean that if you switched off the node (or indeed the root, if that's possible with only two devices) that your clients immediately switched to the other device - the "seamless" experience reported by PC Pro ?

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  • hornbyp
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10 Dec 2020 03:34 #3 by hornbyp
Replied by hornbyp on topic Re: 5GHz Roaming experiments with AP903/AP802

Piste Basher wrote:
A quick question - did you have either or both of the "Fast Roaming" options turned on at any time? i.e "Fast Transition Roaming" and/or "Fast Roaming(WPA2 Enterprise)"


"No" to the first one (I can't for the life of me remember why I've decided that it's not applicable to my setup :cry: ) and "Yes" to the 2nd. I intended to do some specific tests of options like those, but the results were so "woolly", I decided I couldn't measure their effects.


second quick question - by "full blown roaming" do you mean that if you switched off the node (or indeed the root, if that's possible with only two devices) that your clients immediately switched to the other device - the "seamless" experience reported by PC Pro ?


Well it's not a very common scenario, is it? :D
So "no", it's not something I actually tried.

Thinking about it, if the AP that a client is connected to dies, then there's nothing it can do about what happens next. I think you've just invented the concept of the "Access Point Will". "This is the last will and testament of Access Point 'A'. In the event of my untimely death, I'd like all my clients to be adopted by Access Point 'B'"

Blimey, this is starting to get to me :lol: :lol: :lol:

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10 Dec 2020 10:19 #4 by piste basher
Replied by piste basher on topic Re: 5GHz Roaming experiments with AP903/AP802
You're enjoying it really :lol:

As you know, with several AP nodes in my system I tried to achieve the "seamless" experience and failed miserably :roll:

But my main concern at the mo is why my iPhone frequently picks up a "black hole" IP address when I roam around the house. Of course it is showing a strong wifi signal but there is no internet access - until I switch wifi off and on again and it picks up its assigned IP address :roll:

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