Friday, December 14, 2018

Short distance wireless bridge

Two buildings ~60 feet apart. Would like to get usable bandwidth of over 500Mbits.

I tried to use some existing equipment first...doesn't seem to get me what I need but I'll give some details in case I'm missing something....

I have two Cisco 2702i's hanging around to test with (will get access to some 2702e's but that is a week or two away) and I wanted to make sure the 2702's would be sufficient. I configured them with a root bridge/non-root bridge setup so no not a WGB setup.

I could never get them to pass traffic at anything over 450Mbits (reported via iperf anyway) and I need something just a bit higher. I know I'll never get the "advertised" rate in the spec sheets of 1.3Gbit because that includes both radios which don't get aggregated on a point to point link but the 5Ghz *SHOULD* be able to reach 867 (I think that's the number).

We tweaked about everything I can think of in the configuration. Would a patch antenna on 2702e's behave differently or is this the best this thing can do? Having the two i's sitting in the lab 10 feet from each other even with the transmit power turned down still didn't behave correctly (channel bouncing) - it wasn't until I moved it across the building that I was able to run it up to 450.

Here is what the non-root side shows:

Key Mgmt type : WPAv2 PSK Encryption : AES-CCMP

Current Rate : a9.3b8 Capability : WMM ShortHdr 11h

Supported Rates : 6.0 9.0 12.0 18.0 24.0 36.0 48.0 54.0 m0-4 m1-4 m2-4 m3-4 m4-4 m5-4 m6-4 m7-4 m8-4 m9-4 m10-4 m11-4 m12-4 m13-4 m14-4 m15-4 m16-4 m17-4 m18-4 m19-4 m20-4 m21-4 m22-4 m23-4 a0.1-8 a1.1-8 a2.1-8 a3.1-8 a4.1-8 a5.1-8 a6.1-8 a7.1-8 a8.1-8 a9.1-8 a0.2-8 a1.2-8 a2.2-8 a3.2-8 a4.2-8 a5.2-8 a6.2-8 a7.2-8 a8.2-8 a0.3-8 a1.3-8 a2.3-8 a3.3-8 a4.3-8 a5.3-8 a6.3-4 a7.3-8 a8.3-8 a9.3-8

Voice Rates : disabled Bandwidth : 80 MHz

Signal Strength : -47 dBm Connected for : 16783 seconds

Signal to Noise : 48 dB Activity Timeout : 15 seconds

The root side says this:

Key Mgmt type : WPAv2 PSK Encryption : AES-CCMP

Current Rate : a9.3b8 Capability : WMM ShortHdr 11h

Supported Rates : 6.0 9.0 12.0 18.0 24.0 36.0 48.0 54.0 m0-4 m1-4 m2-4 m3-4 m4-4 m5-4 m6-4 m7-4 m8-4 m9-4 m10-4 m11-4 m12-4 m13-4 m14-4 m15-4 m16-4 m17-4 m18-4 m19-4 m20-4 m21-4 m22-4 m23-4 a0.1-8 a1.1-8 a2.1-8 a3.1-8 a4.1-8 a5.1-8 a6.1-8 a7.1-8 a8.1-8 a9.1-8 a0.2-8 a1.2-8 a2.2-8 a3.2-8 a4.2-8 a5.2-8 a6.2-8 a7.2-8 a8.2-8 a0.3-8 a1.3-8 a2.3-8 a3.3-8 a4.3-8 a5.3-8 a6.3-4 a7.3-8 a8.3-8 a9.3-8

Voice Rates : disabled Bandwidth : 80 MHz

Signal Strength : -49 dBm Connected for : 16830 seconds

Signal to Noise : 47 dB Activity Timeout : 30 seconds

The existing gear approach was an interesting science experiment...but mostly a waste of time.

Suggestions on what to use? Looks like autonomous is no longer an option with the 1800/2800 devices but I'm guessing that you can do a bridge+pass VLANs with the mobility express? I need to be able to trunk VLANs over this. I have an aging controller (2504) but I've always preferred autonomous on wireless shots like this.

I'm concerned that the purpose-built ones won't work right since the distance is so short - suggestions, comments, words of wisdom? Of course running fiber would be ideal but this is something I have to get this going in the next few weeks and I haven't been able to find any ducts that cross the "road" (private complex).



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