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08/10/2017
A modest entry into PtP links
Description

IMG_8430.JPG

 

I've always wanted to do a point-to-point link.

 

I've simply never been given the opportunity to until very recently - in fact this link was just commissioned today. Although I did consider doing a PtP at home to connect my free-standing office to the house, but 15m just didn't seem worth the cost and effort so I went with Ethernet over Power for my home office instead.

 

Recently a customer, who I have already sold and installed UniFi switching and access points into, contacted me and said that they were being kicked out of their warehouse space. They had secured a temporary warehouse space for the next 12-18 months and they needed to be able to access their line of business application from that location - including laptops on forklifts with scanners so, wireless.

 

Problem is, they didn't rent the whole warehouse. Only half of it. And not the half that included the comms room. Also, they essentially had only one week to get everything up and running.

 

Floor Plan.png

 

But after some back and forth with potential carriers and their warehouse team, someone mentioned in a teleconference that "it's a shame the Wi-Fi doesnt reach, since it's just around the corner".

 

This is the part where I point out that my customer is in a different state to my office, and if at all possible we should avoid air travel expenses and a whole day of time just to eyeball a site. So to this day I have never seen the new warehouse in the flesh.

 

So when I heard "around the corner" my ears pricked up and I said "oh yeah, how close?" and "what's the address?". So they told me and I jumped onto AirLink.

 

Ubiquiti Airlink for Sky Warehouse.png

 

Less than 550 metres.

 

It may be "around the corner", but both premises back onto a paddock. There is extremely clear line of sight between the back of the factory / head office and the new temporary warehouse location.

 

Huzzah! My first Point-to-Point project!

 

The customer already had some left over / spare Unifi AP AC Pros in the cupboard in their head office so all I needed for this project were two IsoStation 5ACs and a Unifi US-8-150W switch.

 

So I ordered the equipment from my favourite Australian distributor (shout out to Leader Systems) who are also extremely fast with their shipping. Trouble was, they only had stock in Melbourne. Now, that's where the customer is but I am in Sydney and I wanted to pre-configure the devices before sending them to site since they have an engineering team on-site, but nobody technical.

 

My excellent account manager, Andrew, put them on the next scheduled flight to Sydney and I had them around 12 business hours later - for less than $20 freight - which is amazing considering I submitted the purchase order at 5pm.

 

Once they arrived I configured them up and whipped up a quick connectivity diagram for the customer's engineering team to follow in addition to the quick start guide..

 

image.png

 

Now, the head office has 5 Unifi Switches, 8 AP AC Pros and 1 AP Outdoor+ but I simplified the head office diagram for the purposes of this exercise because I mostly needed the engineering team to understand that they could only plug the IsoStations into certain ports. This is because IsoStations use 24v passive PoE so I had to preconfigure the UniFi switches to deliver the correct power.

 

There is no server at the warehouse and there is no way I am using a wireless link in true layer-2 bridge mode and extending the failure domain so I set them up as an Access Point Router at the head office and a Station Router with DHCP Server, but no NAT. I created a dedicated link network between the two IS-5APs and put a static route on the Access Point side so that it knew about the downstream network. A pair of static routes and a NAT on the main firewall in head office and I have just safely extended the LAN zone into a nearby building.

 

My follow up task will be to swap from using the on-board DHCP Server to using a DHCP Proxy pointed at the domain controller so that I can issue a default domain name - only problem with the built-in services - and have a central location to manage leases and reservations.

 

Upgraded the firmware for giggles, packed them back up and put them on the next plane back to Melbourne to the attention of their head of engineering.

 

The next day the customer went to work installing the radios to my specifications, having already discussed possible mounting locations with their engineers. Now, the customer is actually on airport land, so you need a development approval to erect even a small pole on your roof, but luckily for us there was a catwalk on the roof of head office.

 

IMG_8430.JPG

 

See that building just left of the centre? That's the target.

 

I also understand that, near an airport you also need to avoid the DFS channels and generally limit radio signals to a minimum so the isolation antennas of the IsoStations were very appealing as I am guessing that with beam-forming you can run at lower power. The next step will be to dial down the radio power bit by bit to see how low we can get away with at such close range.

 

Over on the other end, because we had a wall with direct line of site, adding a mounting pole that did not exceed the height of the original building was simple for mechatronic engineers.

 

image.png

 

So that's me dipping my toes into the world of point-to-point. But never one to be completely boring, I did the whole thing without leaving my desk in a different state thanks to the simplicity of AirOS and UniFi, along with an RMM to give me remote access to their systems.

 

Right now I can jump on to their file server and connect to the management interface on either radio.

 

image.png

 

Meanwhile, go back and compare the real-world speed test below to the estimate from AirLink above. Pretty decent estimate, i'd say - which is what you want from a planning tool.

 

image.png

 

All in all by using Ubiquiti the whole process of remotely deploying a wireless link was cost effective and extremely painless.

 

Yeah, I'm a fan :-)

Comments
by
on ‎08-10-2017 06:12 AM

Wow, that sh*tty indoor utp cable won't last long Smiley Sad

by
on ‎08-10-2017 06:18 AM

Nice project and an excellent write up. We do the same thing time to time with larger customers that are spread out accross the US.  Here's to more PTP's in your future!!

by
on ‎08-10-2017 08:00 AM

Nice write up! I'd suggest decreasing your channel size to something like 20 MHz. You ought to have a better, more stable link, that is less susceptible to noise that crops up within your current 80 MHz view. Just do the far end first, and you could even use the Test feature. Capacity may be a little less, but probably more than sufficient. What's the speed of the internet connection? If it's 100 Mbps, you might still be able to get that with a 20 MHz channel.

by
on ‎08-10-2017 08:52 AM

 

Very well written and detailed story - thanks for sharing!

 

Regards,

Ross.

by
on ‎08-10-2017 10:55 AM

nice job!  I've used similar wider-angle shots for over-the-phone setup since people can't aim a focused dish to save their lives.

 

That indoor cable will be an issue in ~2years, that's about what I've seen them last.  Maybe less if it's in harsh sunlight most of the day.

by
‎08-10-2017 04:50 PM - edited ‎08-10-2017 04:57 PM

Thanks for the encouragement guys!

 

@rebelwireless@vicent_nb1,

 

The cable was the first thing I noticed when they sent the photos (that and the missing bolt on the warehouse pole - and the missing gasket/grommet ). The guys just used some of a left over spool they had laying around from an indoor UniFi project.

 

Since the setup only needs to last 18 months at the most, I didn't make a big song and dance about the cable but I am getting them to see if they can find the missing gasket and pop it in.

 

If they move to a permanent warehouse space that is also a viable wireless case I'll be looking at getting them to replace the cabling at that point.

 

@elmorekevin,

 

I do understand that narrower bandwidths are more stable, but at 550m i'm receiving full signal on both units so I thought i'd just leave it like that.

 

The Internet is currently being upgraded to 100 Mbps but the fact is that the warehouse is blocked from using the Internet anyway. They only have LoB application access which is IBM i (AS400) green screen which uses a miniscule amount of bandwidth.

 

Once some computers are in I will do some experiments to see if reducing the bandwidth helps with latency at all (from reduction in packet loss and retransmission for example).

 

Cheers,

 

Michael

by
on ‎08-10-2017 06:29 PM

if you dont find a gasket put a drip loop in the cable and some butle.

 

by
on ‎08-10-2017 09:12 PM

Great story, excellent write up, always like to see more Australian stories here.