nanog mailing list archives

Re: Ghosts in our 6 New Ubiquity Pros - provision issues.


From: Mike Hammett <nanog () ics-il net>
Date: Fri, 19 Jun 2015 11:30:08 -0500 (CDT)

The UBNT controller is only required when setting up the APs or for certain guest portal functions. I'd just leave it 
connected all of the time. 




----- 
Mike Hammett 
Intelligent Computing Solutions 
http://www.ics-il.com 



Midwest Internet Exchange 
http://www.midwest-ix.com 


----- Original Message -----

From: "Bob Evans" <bob () FiberInternetCenter com> 
To: "Steve Naslund" <SNaslund () medline com> 
Cc: nanog () nanog org 
Sent: Friday, June 19, 2015 11:26:42 AM 
Subject: RE: Ghosts in our 6 New Ubiquity Pros - provision issues. 


That's possible but I if they are re-provisioning on a regular schedule I 
kind of doubt it. It would be easy to test though. Plug an AP directly 
into your switch with a quality pre-manufactured patch cord and see how it 
acts. If it exhibits the same symptom it is probably not cabling. Also, 
have you checked your interface counters for any packet errors? 

Yes, no packet errors crcs or frags. 

Don't 
forget to look at your controller because if the controller became 
unreachable for any length of time that could easily cause your APs to 
re-provision as they reconnect with the controller. 

This is did not know - thought the controller was just to provision and 
monitor. After all why would a manufacturer make one point of failure for 
a campus setup that uses thier own edgerouter for the dhcp etc. Doesnt 
seem correct. But will will investigate it. 

I might set up a ping 
every second from the site of the access points to the controller and make 
sure the availability of the controller is 100%. 

Yes that and what the ciscos report on the port link. 

If you are on Cisco 
switches you should have log messages regarding PoE be granted on 
particular ports as well as up down messages on the interfaces. 

Yep and we get them. 

Do you 
see the ports going up and down? It is important to have NTP on the APs 
and switches so that you can correlate events in time (i.e. did the AP 
reboot causing the Ethernet link to drop or did the link drop causing the 
reboot?) 

I am sure its the APs dropping - as non of the other devices VOIP phones 
etc drop in the logs. 


Thanks Steven 
Bob 

Steven Naslund 
Chicago IL 


Bob, I've deployed tons of Ubiquiti gear, and have seen this problem 
before. It always turns out to be poor quality cable installation. POE 
does not tolerate low quality connectors, especially in outdoor 
environments. There are >many aspects to a quality cabling job, so the 
best thing you can do is seek out a qualified installer with outdoor POE 
experience. 

The most common problem I see is people using crimp-on RJ45 connectors 
directly on the ends of their cable runs. This is not how structured 
cabling is designed to work, in particular because most crimp-on 
connectors are intended for >stranded copper wire (such as that used in 
very flexible patch cords, designed to run horizontally over only a few 
dozens of feet), whereas the "riser" and "plenum" cable used for 
long-distance runs has solid core wires. The tiny >teeth in standard 
crimp connectors are designed to penetrate stranded wire, to make a solid 
electrical contact. With solid core wire, they just bend to the side of 
the copper core, making tenuous contact, which will conduct POE >current 
poorly (resulting in the resets you see) and eventually fail altogether 
as the improper connection corrodes over time. 

The correct installation process is to use "punch-down" RJ45 jacks at 
each end of the cable run, and connect from those jacks to your equipment 
(radio at one end, POE switch at the other). On the outdoor side, the 
jack/plug junction >needs to be in a NEMA weatherproof enclosure, with 
weathertight fittings. And, for human and equipment safety, you must use 
shielded Cat5e/6 cable anytime you go outdoors, grounding only one end 
(usually the radio end), and >protecting the cable with an inline 
lightning protector between the RJ45 jack and the radio. 

If you haven't done that, then that's the first thing to fix. 

BTW, avoid homemade patch cables whenever possible. Quality factory 
cables are hydraulically pressed and the plug is hermetically fused for a 
vastly superior connection compared to anything you can do with simple 
hand crimpers. And >all outdoor cables must be UV-grade cabling with 
weatherproof sheathing and water repellant inside (so-called "flooded" 
cable). 

-mel beckman 






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