50 Efficiency

I have a small network setup for one client and we’re having troubles with it. We have one 2450AP with Omni antenna, and two 2400SM’s. The AP is located between the two buildings and each building has an SM connecting to the AP.

Site A gets 7/7 mbps and near 100% link tests but site B gets 3.5/3.5 mbps and near 50% link tests.

Here’s the details from site a:

Session Status - REGISTERED VC 19 Rate 2X/2X
Registered AP - 0a-00-3e-23-XX-XX
RSSI - 1232
Jitter - 7
Air Delay - 36 (approximately 0.33 miles (1764 feet))
Radio Slicing Value - 592 (decimal)
Radio Transmit Gain Setting - 18 (decimal)
Radio Power Level - -51 dBm
LUID - 3
IP Address - 192.168.101.3
Registration Grant Status - Normal
Sustained Uplink Data Rate - 3500 (kbps)
Uplink Burst Allocation - 500000 (kbits)
Sustained Downlink Data Rate - 3500 (kbps)
Downlink Burst Allocation - 500000 (kbits)

Link Test:

Stats for LUID: 3 Test Duration: 5 Pkt Length: 1522
Downlink RATE: 7291699 bps
Uplink RATE: 6345523 bps
Downlink Efficiency: 98 Percent
Max Downlink Index: 100
Actual Downlink Index: 98
Expected Frag Count: 71208
Actual Frag Count: 72046
Uplink Efficiency: 99 Percent
Max Uplink Index: 100
Actual Uplink Index: 99
Expected Frag Count: 61968
Actual Frag Count: 62122

Here’s the details from site B:

Session Status - REGISTERED VC 18 Rate 2X/2X
Registered AP - 0a-00-3e-23-XX-XX
RSSI - 1451
Jitter - 3
Air Delay - 18 (approximately 0.17 miles (882 feet))
Radio Slicing Value - 694 (decimal)
Radio Transmit Gain Setting - 20 (decimal)
Radio Power Level - -48 dBm
LUID - 2
IP Address - 192.168.101.2
Registration Grant Status - Normal
Sustained Uplink Data Rate - 3500 (kbps)
Uplink Burst Allocation - 500000 (kbits)
Sustained Downlink Data Rate - 3500 (kbps)
Downlink Burst Allocation - 500000 (kbits)

Link Test:

Stats for LUID: 2 Test Duration: 5 Pkt Length: 1522
Downlink RATE: 3661824 bps
Uplink RATE: 3307929 bps
Downlink Efficiency: 49 Percent
Max Downlink Index: 100
Actual Downlink Index: 49
Expected Frag Count: 35760
Actual Frag Count: 72052
Uplink Efficiency: 50 Percent
Max Uplink Index: 100
Actual Uplink Index: 50
Expected Frag Count: 32304
Actual Frag Count: 63549

Anyone have any ideas as to why this is happening?

Site B is running 10 mbps modulation?

50% on the up and on the down…Do you LOS to the OMNI from Site B?

Both sites have 2x enabled and both sites have LOS to the AP.

What happens if you disconnect the RF connection from Site A to the AP, then test Site B?

Have you tried power cycling everything? I have seen backhauls report 50% link efficiency tests, then after rebooting everything went back to 100%.

Can you be a bit more explicit in describing “between 2 buildings”? Where I am headed with my question has to do with reflections. If the 2 buildings are “close enough” (especially if the building WITHOUT the problems is really close to the AP), then you MIGHT be fighting reflections of the RF signal ‘off’ of the closer building reflecting into the antenna of the SM that is giving you problems.

If the problem SM is getting a reflection that is timed “just right” (or “just wrong”), then the reflected signal can be received out-of-phase which can corrupt the original signal.

Long description (my apologies).

So, is the AP located between the two buildings - is the non-problem building closer - are the buildings facing a ‘flat face’ towards each other?

If the line directly between the two buildings is the hypotenuse of a right triangle, the AP would be at the right angle.

The one that is having trouble is the one that is closer to the AP.