Kurt, I have some comments inline.
From: Af [mailto:af-boun...@afmug.com] On Behalf Of Kurt Fankhauser via Af Sent: Saturday, October 18, 2014 2:20 AM To: af@afmug.com Subject: Re: [AFMUG] Pmp450 vs epmp pros vs cons I started the spring deploying 450 in 2.4ghz, 5ghz, and 3.65ghz and then middle of the summer deciding i had to"try" some ePMP because the cost was so low I couldn't resist.... I can say now that I am fairly certain I will probably stick with the 450. There are many small reasons that when I considered them all i came to this conclusion. Here are my reasons: 1. ePMP latency starts to go up quickly once you have more than 10 clients on an AP. Once you get over 20 clients the latency is pretty much 25-30 ms. Cambium was honest about this at the road tour and they noted if you want the best latency to stick with the 450. The BIGGEST factor on ePMP (or any 802.11) is quality installs EVERY time. You cannot have borderline customers (lots of retransmissions in the stats) or you will really hurt the APs ability to do its thing. This is not new to 802.11, but very different from regular Canopy gear. You have to raise your standards of what is acceptable from a SNR and link test capability. Our standard is evolving on this, but if we have a radio performing at less than 50% of maximum capacity, we don’t accept it. We do whatever it takes to get better LOS (or NLOS). 2. Sync between the two platforms is not there yet. If you have adjacent towers on the different platforms that can see each other you won't have sync. Sync is coming Cambium has promised. 3. No remote spectrum analyzer for clients. This is HUGE for when the clients fire up their wireless camera and baby monitors and trash the whole spectrum. Agreed. Remote SA is needed. eDedect does a pretty good job and picking things up and we use Mikrotik routers inside the home to help diagnose Scan/Snoop whats going on inside the home. This has been HUGE for us. 4.No burst bucket on CPE's. Agreed. Though we manage burst / sustained at the head-end 5.EPMP Interface is SLOWWW. Cambium explained at the tour they were offloading alot of processing power to the PC you are viewing the interface with and i can't be taking a quad core machine up a tower to work on these radios and do site surveys. I am working with a Panasonic Toughbook and takes FOREVER to log into the EPMP radios. Agreed. If the PCs would cache the Java libraries that come down to the PC, I think they would solve the problem. I have suggested that o Cambium. 6. Fore some reason site surveys are a PITA with ePMP. Think its a combination of many factors here... slow interface one of them... hmmm… not had an issue… our installers say they are easy. The LEDs’ get you very close, then someone else tweaks them (another tech onsite or remotely from the office. But, yes, the interface could be quicker. 7. EPMP in 5ghz DFS band has really low power output. Something like 13-14db. This has fixed in later firmware versions. When using an omni antenna you can't get maximum legal EIRP out of the ePMP. 8. 450 link tests and SM modulation is pretty stable and predictable. EPMP seems like its all over the place. I don't think I have yet seen EPMP linktest get full up or down outside of a lab environment. We have customers getting 110Mbit aggregate on their link test in the field (UDP of course). There might be other reasons but I'm pretty tired and was heading for bed. Kurt Fankhauser Wavelinc Communications P.O. Box 126 Bucyrus, OH 44820 http://www.wavelinc.com<http://www.wavelinc.com/> tel. 419-562-6405 fax. 419-617-0110 On Fri, Oct 17, 2014 at 5:05 PM, TJ Trout via Af <af@afmug.com<mailto:af@afmug.com>> wrote: I haven't been keeping real up to date on current generation ptmp offerings but we have a new site going up and I need to decide pretty quickly on some equipment. For the guys who have been using both 450 and epmp do you have any pros and cons ? Any reason to spend the extra money when epmp seems to have the same if not better performance , sync, etc? My gut says 450 is going to be my best long term solution but with all of the positive epmp feedback it's hard to justify the extra money?
