Tag Archives: Point to Point

A Little Point-to-Point Bridge Saves The Day

Last weekend I was trying to finish up an IP CCTV project at one of my favorite customer sites. Here, an electrician was supposed to run the UTP and I would terminate and test it before I connected cameras. It should have been a straight-forward endeavor, but it got weird. I blame my own lack of attention to detail in telling the electrician EXACTLY where one wire needed to go. Because I didn’t, he put it someplace that was easy for him, but impractical for the application. The camera would somehow have to see around a substantial corner if I mounted it where the wire landed.

Allow me to leverage my Enormous iPad Pro and $700 pencil to make a simple site drawing:

Do you see the problem? There was really no practical way to get the UTP extended to where it needed to be, which would be right about where the outlet is drawn (about 10 meters away). Hmm. I had a good station cable that happened to be in the wrong place, and I had an electrical outlet under an overhang where I needed the camera to go. My wheels started to turn…

Are you starting to smell what’s cooking here? Let’s add a couple of things to that world-class drawing.image

By golly- that just might work.

Being a well-connected Man of Action, I happened to have a couple of 5 GHz Cambium ePMP 1000 in my bag of tricks. Sure, some might say the bridge link I was about to build– spanning all of around 30 feet– borders on overkill for this application. But you do what you gotta do, and I don’t really like wireless cameras. But I do like good point-to-point links for wired cameras.

The Cambiums are an elegant, cost-effective way to do links this short as well as miles longer if things line up right for you.  I updated the firmware on the bridges, gave them the simple config they needed to take their place on my network, and made sure the channel in use wouldn’t conflict with the business WLAN in place.

After a quick trip to Lowes, I was fairly pleased with my solution.



That 8″ square electrical box houses the power injectors for both the camera and the bridge, It will probably get painted along with the box the camera is mounted on to better blend in with the white of the overhang, and the owner blessed this unconventional setup as the camera is really important to them.

So how does it work? Though there is still a bit of camera alignment to be done, it’s a pretty good view from the camera.  This particular view is from a remote viewing app, but at the DVR the image is crystal clear and never stutters or drops. After a few days of testing, this link performs as well as a patch cable.


Like I said… sometimes you do what you have to do.

A Different Kind of Wireless Bridge, From AOptix

Just as the world of wireless client access has evolved over the last decade, so has the point-to-point bridging space. Though I don’t do a tremendous amount of bridging, I have done a couple of dozen production links using a variety of licensed and unlicensed technologies. And through the last several of years, I’ve absolutely marveled at the advances in point-to-point bridge hardware as pricing in this interesting space have come way down versus what you get for your dollar.

For me, bridging is really fun in that it reminds me a lot of amateur radio- with the rooftop/tower work, the need to select the right band for the application, and the importance of proper installation if you want communications with a far-off station to work right.

Before I get into the real point of the blog (a new bridge product), let’s take a quick detour. At both of this year’s Interop sessions in the US (Vegas and NYC), Kieth Parsons did an awesome presentation on extending the LAN with point to point bridging. If you missed it, you can find Keith’s slides, and almost all of the Interop NYC sessions, here. Don’t feel lonely if you don’t have point to point bridging experience; a recent survey I did of well over 300 WLAN professionals showed than more than half don’t do anything with bridging.


If you want to start learning about bridging, Kieth’s slides will likely kindle an interest and provide value.

Warning: Cool Technology Ahead

Back to why we’re here: the AOptix Intellimax product set, and in particular the MB2000. There are a number of impressive points related to this bridge:

  • 2 Gbps of throughput to 8 km (just about 5 miles) even in the worst weather. There is NO autorating, you always get 2 Gbps
  • Need more than 8 km? Daisy-chain ’em
  • Free-space optics are coupled with RF for dual-tech signalling that AOptix calls Composite Optical RF (COR)
  • When conditions are bad for one technology, the other picks up the slack automatically. AOptix calls this Advanced Wavelength Diversity, or AWD
  • The units are made to mount easily, and align in around 20 minutes, compliments of a feature called PAT (Point, Acquire, Track)
  • Beam-steering allows for up to 6 degrees total of tower/mast twist and flex (+/- 3 degrees)

There’s a lot to digest here, and it’s impressive. The free-space optics side of the MB2000 has a 120 mW license-free (worldwide) transceiver, while the RF side’s 80 mW works in 71-76 and 81-88 GHz spectrum. This means in countries like the US and UK, it’s “lightly licensed” in that you fill out paperwork, pay the fee, and you’re good for 10 years.

I was approached by AOptix’ PR folks wanting me to cover a deployment done in Mexico where the Intellimax supposedly did very well. I’m not a huge fan of case studies unless I can write about something I’ve been involved with first-hand, yet I find the AOptix story to be compelling enough to share here. I wasn’t provided with pricing information, but given that we’re talking “carrier grade” gear, expect it not to be priced like lower-capability bridges.

You can picture this sort of bridge being suitable in 4GE backhaul, military and public safety networks, large campuses, and a range of other applications.

Please have a listen to a quick podcast I put together on the topic as well.

I’d love to hear from any readers on whether they have experience with AOptix, or have found any other bridging solutions (low or high-end) that they like- or hate.

A New Point-to-Point Bridge, Some Impressive Numbers

Point-to-Point bridges are a fascinating part of wireless networking. As I’ve written about before, both in this blog and for Network Computing Magazine, I have designed and installed a number of links through the years. The rooftop work isn’t my primary gig, but I frequently design, align, troubleshoot, and occasionally install this incredibly enabling technology.

Even if you don’t work on wireless bridge links, it’ easy to appreciate the notion of making network where there is none, and pushing respectable bandwidth through the air thousands of feet, or dozens of miles.

I recently got wind of Cambium Networks, a company that specializes in the bridging side of wireless. Cambium is worth getting to know if you are looking around for bridging alternatives for point-to-point, point-to-multipoint, and other topologies.

Cambium has recently released their latest PTP model, the PTP 650. So what? New bridges get released fairly frequently from lots of companies, right? I found myself hooked by the range claims associated with the PTP 650.

From the release:

 PTP 650 shines in harsh environments: It is able to transmit up to 120 miles (193 kilometers) over water and desert and from ship to shore, and platform to ship. It is the most reliable NLOS (non-line-of-sight) wireless broadband solution on the market for well field automation.

There was quite a more to the PR, and it’s all impressive enough.  The PTP 650 works between 4.9 and 6 GHz, at a variety of channel widths and with different modulation types that can deliver up to 450 Mbps throughput for under $5K. That’s the condensed version. But if you know anything about bridging, anything that claims to go 120 miles wirelessly bares investigation. Lets look at that rate-versus-range thing.

Lot’s of wireless bridge makers provide “link calculators” which help designers know what to expect as they plan new installations. How far can you go with a given hardware set and still get the throughput you’re after? Here’s Cambium’s Link Planner. To cut to it- here’s what Cambium told me when I asked what the 650 could do at different lengths (without external antennas, using the built-ins)-

Example: Line of Sight; 5.8GHz spectrum; integrated 23dBi antenna; 45MHz channel bandwidth
Range (miles)
Maximum Aggregate Capacity
370 Mbps
220 Mbps
150 Mbps
45 Mbps

To me, this is impressive, as 45 Mbps is still a fairly beefy connection depending on what’s on the other end. At the same time, I can’t imagine trying to align a 100 mile link!

Having never used Cambium products or software, I’m not endorsing the PTP 650 here, but can appreciate what it’s out to solve (even a couple miles can be difficult at alignment time).