Wireless bridge

Peter Boone NANOG at Aquillar.com
Mon Apr 5 17:41:40 CDT 2010


Hi Mike,

Sorry for the misunderstanding, allow me to paraphrase: the link does not
drop, actual throughput is now faster than our internet connection, and
transfers have not been interrupted, so we are happy. As I mentioned, our
previous setup could only work reliably when locked at 6 Mbps, and even then
there were interruptions and mysterious downtime, so a 54 Mbps theoretical
max rate has been a godsend. Also, there were no "shiny sales brochures"
involved in the decision, the Bullet2's were the most cost-effective
solution to get the job done, and at minimal loss if the odd problems were
not actually solved (see the archive of this thread from June 2009 for
details).

Bret,
You are correct, the Bullets are on max output power right now so they are
loud, and I just found that Ubiquiti recommends aiming for -50 to -70 dBm
"for stable links". I always looked at the hot signal issue like a bad
quality speaker turned up too loud; where in this case the speaker is the
wireless radio. Since there have been no wireless errors and (aside from a
small number of expected Invalid Network ID errors) and the dBm is high I
figure the signal is loud and clear on each end, but I'll be sure to tweak
the power output. There have actually been more error packets on the wire
than in the air (0.000001% of LAN packets). 

Regards,

Peter

-----Original Message-----
From: Mike [mailto:mike-nanog at tiedyenetworks.com] 
Sent: April-05-10 4:02 PM
To: Bret Clark
Cc: nanog at nanog.org
Subject: Re: Wireless bridge


No, you are not pushing a stable '54mbps over the link without issue'. 
More likely, if you cared to look, you are getting somewhere around 
30-35mbps, HALF DUPLEX. The '54mbps' advertised on the shiny sales 
brochure, is a signaling rate and not a measure of thruput.

Mike-

Bret Clark wrote:
>    Peter Boone wrote:
>
>
> I purchased 2x Ubiquity Bullet2's (2.4 GHz) and utilized our existing
> antennas. It has been working extremely well, pushing a stable 54 Mbps
over
> the link without issue. Signal strength is consistently -40 dBm +/- 2 dBm,
> from about -80 dBm before! Total cost included 2x Bullets, 2x PoE
adaptors,
> and approx 40 ft of STP cat5: $120. I have yet to see what happens in a
big
> thunderstorm, but I extrapolate that they will be able to handle the EMP
> without going haywire like before. They have worked very well through
> conditions that our last setup would not.
>
> Thanks again for the input everyone!
>
> Peter
>
>    More an FYI as I'm not overly familiar with Ubiquity's, but I believe
>    -40dBm is kind of a hot signal which means they are screaming at each
>    other, are you seeing any physical errors, specifically CRC's?. Won't
>    necessarily affect overall throughput, but -60dBm is the sweet
>    spot...too much of a signal is just as bad as not enough...sort of like
>    that Sienfield episode of the the close talker :).
>    Bret
>   






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