@bleger wrote:
On another note, we're using 3.65 ubnt gear also and I'm seeing a lot of self interference. In your in your opinion, should I scrap 365 ubnt and go with 2.4 cambium synced gear? Your throughput story is amazing and if I can get that type of thoughput with a better propagation than 365, we'd probably double our customers in no time.
Hi. Well, in my experience - self-interference is THE biggest problem, and it's also (fortunately) a problem that we as WISPs have the best abililty to control. Competitive interference and 'environmental' interference typically isn't actually as large a problem usually (since the noise levels are usually lower than your self-interference signals) and in most cases, you can't really do to much about it anyway. So - Cambium's GPS sync technology has very wisely targetted A) the most important source of interference (which is self-interference) and targetted B) the interference that we can most effectively control (which is self-interference). However - this post is about how well Cambium ePMP does deal with a noisy 2.4Ghz environment, and how effective it is performing in that noisy enviroment.
I should also say, we do use some non-Cambium 3.x Ghz gear for backhauls, and when they have solid directional dishes, we've been OK with their results. However, in MultiPoint AP's, we're 2.4ghz and 5Ghz and 900Mhz (Canopy FSK) only. And now that we've experienced what ePMP can accomplish, we are changing all our 2.4Ghz stuff over to Cambium ePMP (~2,000 CPEs).
Personally - I can't say enough about Cambium's 2.4Ghz performance in a noisy enviromment. As I related earlier, the first place we deployed it was on the AP that I am connected to - since that is right in town and in about the harshest RF environment we expected to find. Our ''non-Cambium'' gear used to work OKish (we thought) a few years ago in this situation, but as the number of routers increased everywhere & as competitors deployed their 2.4gzh gear - the performance dropped so that at peak times, we would be lucky to get ~ 1 Mbit through it.
So, when we got Cambium gear in, I thought - this would be the perfect environment to test. I frankly expected it to fall flat on it's face too. In this case, I could connect the AP to the existing sector, and I could connect the SM to my existing DualPol grid antenna. It was the PERFECT environment to test the difference because nothing would change - same antennas, same mounts, same aiming, same channel - everything.
So, we got our sample gear in and I think it even took me a few weeks to get around to changing it out. I really throught it was a waste of time - 2.4Ghz is dead dead dead, right? But I went and changed the AP and my SM out - 'just to see'... and to my shock and amazement... throughput went DRAMATICALLY UP. I have my SM's ''QOS'' set to 10 Mbit download and 1Mbit upload - and the following screen shot shows the AP's perspective, and what I'm getting right now at the moment.
I've also included a ping sample on this image too. That's another HUGE difference - way more stable ping times. This is pinging from my laptop, through my router, through my ePMP SM, ~4KM to the ePMP AP, and through our backhaul to our Internet Gateway. With our previous non-Cambium gear, which was non-GPS-Synced of course - the ping times "could" in theory potentially be lower. BUT in practicality, they were all over the place because that gear had such a difficult time dealing with the noisy environment. The 'non-Cambium' gear was 1-2ms at 3:30 AM if I wasn't using it for anything except testing my ping times, but it could be anywhere from 2ms to 200 ms during peak times, and certainly if I was trying to download something - the ping times would be 200-600ms when the connection was saturated (with 1 or 2 mBit of data). Now I can put my full 10 Mbit QOS through it and the ping times are about the same as when it's sitting idle.
NOW - even Cambium is not magic and obviously there are going to be situations where it still struggles. Frankly, even at my place here, when I look at the packet % distribution, I can see it's having to do quite a bit of re-transmit and that there are dropped packets - so it's not like ePMP is immune to interference. But Cambium's GPS Sync, it's Air Fairness TDMA, it's highly organized scheduler - they all add up to ePMP working where other's fear to tread.