~2MB/sec performance OK for WG103?

[georgep54]

Hello-

I have 3 prosafe WG103 switches, and the FTP file transfer rate I get when copying a file between two connected nodes in the network, is 2MB

Is this acceptable or should I be seeing better performance?

Thank you very much!
George

##

FTP between two nodes, both over wifi WG103

[R] 226 Transfer complete
Transfer queue completed
Transferred 1 File (1.34 GB) in 12 minutes 16 seconds (1.86 MB/s)


FTP over switch gigabit uplink (both nodes on gigabit uplink ports of FS726TP)

[R] 226 Transfer complete
Transfer queue completed
Transferred 1 File (879.99 MB) in 24.48 seconds (36.05 MB/s)

[fordem]

As you have discovered WiFi is not the greatest medium for bulk data transfers, and a lot will depend on the environment...

First - you're using 802.11g so you are limited to a theoretical maximum of 54 mbps, which translates to somewhere in the region of 20~30 mbps throughput - or 2~3 MB/sec - and yes, I do know it's 8 bits to a byte, your data transfer will also include addressing, check sums, etc, so there is some "overhead" that needs to be accounted for.

Next - Wifi is half duplex - the radios can not transmit & receive at the same time, and there is a certain degree of "switching latency", which causes a further degradation of potential throughput.

Last - transferring data between two WiFi nodes associated with the same access point (whch may or may not be the case in your particular scenario) requires special consideration - the sequence of events goes like this ...

- Node A transmits to the access point
- Access point switches RX/TX modes.
- Access points transmits to Node B.
- Access point switches RX/TX modes.

The above sequence ignores (for simplicity) the acknowldegements and so on required by the protocols, which would actually further reduce throughput, but from it, you can see that the 2~3MB/sec projected throughput is actually reduced to under 50% - and this is not even a worst case scenario - it's a "single access point scenario"

Best case scenario - your WiFi nodes are associated with different access points in which case the 50% degradation MAY be eliminated, depending on what's actually happening with the other network traffic.

Worst case scenario - you have interference between your multiple access points and CA (collision avoidance) kicks in, further degrading throughput.

I'd say your 1.86 MB/sec is not bad, it could be better, but it could also be worse.

[georgep54]

Many thanks for the detailed response, it was very helpful!

Only one more question please:

Most of the clients in this wifi network will be iPads, and i have seen iPads are known to be "sticky" with the wifi access points they first pick up.. even though they may be closer to a stronger wifi signal.

In my setup i have the 3 WG103's configured like this:

wifi_01 -> point to multi point (located in center of the house)
wifi_02 -> point to point (located 10m west of wifi_01)
wifi_03 -> point to point (located 10m east of wifi_01)

I thought with this setup I would only have 1 SSID and wifi_02/03 would act as repeaters. Was this wrong? I still see 3 SSID's when I try to connect..

Would you please suggest a way to configure these 3 AP's so that the iPad's can roam freely in the three zones, and only show as one wifi ssid?

the logical positioning is this:
wifi_02 >> (10m distance) wifi_01 (10m distance) << wifi_03

Thanks again for your kind help!

[fordem]

First - I'm not familiar with the iPad, however on Windows systems there is a setting for what can be described as "roaming aggression" this is what determines how aggressively the device will search for stronger signals.

Second - if you are using different SSIDs the iPad (or any other wireless device) will consider your access points to be different wireless networks and will not roam, but will do their best to stay connected to the chosen network.

[Marto73]

George,
You are far better doing File transfers wired, full duplex, rather than
using wireless.
Can wifi_01, 02 & 03 be set on different channels, ie 1,6,11.

I think 10metres apart is too close. That is giving each a 5metre radius.!!
Can you take one out, and use 2, at 20m apart, for comparison.


Regards,
Marto,
Netgear