ePMP 3000: How to test MU-MIMO

http://community.cambiumnetworks.com/t5/ePMP-3000-MU-MIMO/ePMP-3000-How-to-test-MU-MIMO/m-p/102882

Intial MU-MIMO testing after deployment can be performed through the built-in Wireless Link Test Tool.On Wirless link Test page new option has been added for ePMP3000 – Mode. Wireless Link Test can be started to Single SM or to Dual SMs simultaneously.

ePMP tip of the day

http://community.cambiumnetworks.com/t5/ePMP-FAQ/How-does-the-GPS-Sync-Radio-utilize-the-Active-and-Inactive/m-p/82855#M143

ePMP GPS Sync Radio devices that have an onboard GPS contain two banks of flash memory which each contain a version of software.

The version of software last installed onto the device flash memory (using software upgrade procedures) is configured in the Active Bank. This software will be used by the device when the device is rebooted.

ePMP eDetect

One of the biggest tasks on a wireless AP is finding clean channels.  Once you find those clean channels, making sure you stay on a clean channel is the next task. ePMP has a feature under tools called eDetect. One of the things this can do is give you an idea of how many devices are on a given frequency.

The ePMP AP you see above is on a 20mhz channel, which is why many home routers and other devices are showing up.  If this was on a cleaner frequency it would look like the following.

While eDetect is not a replacement for spectrum analysis, it can give you a pretty good idea of what’s using a particular frequency.  Please note, you see the most things on 20MHZ channels because that is what most home routers are set to. If you would like to read up on eDetect in more detail go here: https://community.cambiumnetworks.com/t5/ePMP-Configuration-Management/ePMP-Tools-eDetect-Explained/td-p/42997

BGP Monitoring RFC 7854

https://tools.ietf.org/html/rfc7854

   This document defines the BGP Monitoring Protocol (BMP), which can be
   used to monitor BGP sessions.  BMP is intended to provide a
   convenient interface for obtaining route views.  Prior to the
   introduction of BMP, screen scraping was the most commonly used
   approach to obtaining such views.  The design goals are to keep BMP
   simple, useful, easily implemented, and minimally service affecting.
   BMP is not suitable for use as a routing protocol.

BGP Confederations

In network routing, BGP confederation is a method to use Border Gateway Protocol (BGP) to subdivide a single autonomous system (AS) into multiple internal sub-AS’s, yet still advertise as a single AS to external peers. This is done to reduce the number of entries in the iBGP routing table.  If you are familiar with breaking OSPF domains up into areas, BGP confederations are not that much different, at least from a conceptual view.

And, much like OSPF areas, confederations were born when routers had less CPU and less ram than they do in today’s modern networks. MPLS has superseded the need for confederations in many cases. I have seen organizations, who have different policies and different admins break up their larger networks into confederations.  This allows each group to go their own directions with routing policies and such.

if you want to read the RFC:https://tools.ietf.org/html/rfc5065

Journey into Ham radio and DMR

This was originally published at http://www.mtin.net/blog/journey-into-ham-radio-and-dmr/ .A little has changed, including my call sign since it was published. However, it alot is still relevant.

-n2jsw

For years I have hung out with “Hams” and been somewhat interested in the technology.  Guys like ka8jil, w9sn, w9smj, w9cjo, w9abh have all interested in me in ham radio. I remember many years ago, before cell signals were digital, being able to pull up to a car and watching my buddy Tom tune his radio in and listen on the cell conversation going on in the car next to us.  For educational purposes only of course.  It reminded me of the blue and Red box days of telephone phreaking.  The days of the 300 baud modems and making init strings to make the best possible connection.  For me, and I think I am like many other folks, it wasn’t the draw to the hobby, but rather all of the moving pieces of it which kept me from taking the step into it.  Traditionally Hams have tuned and tuned their radio setups, with many building their own antennas.  I can see where tuning a “shack” to get the best you can get out of it can be a challenging and rewarding thing for many.  Picking the right hardline, connectors, and other pieces takes alot of research, and some trial and error to make it function cohesively.  Tracking down noise, little hums in your transmissions, and other things is a problem solving logic that can stimulate the brain.

repeater

Motorola DMR Repeater wb9arc

But, I am not a true hardware guy.  I am more of a wizard at making it do what I want within the bounds of the software.  If I can make an add on to interface with something existing then thats as far as my interest goes.  This is what we were doing “back in the day” with blue boxes then moving on to the commodore 64. Being able to bypass copy protection, spinning up hardware keys to bypass restrictions, and stretching the limits of what the software could do with hardware add ons.  Then along came the Internet and dial-up modem banks, ISDN, T1s, etc.  All these were technology which could be pushed with “add ons” and “hacks” to something existing.  This is where my attention is really stimulated.  To me, Ham Radio has always been about taking all these different pieces and trying to make something work.  Kind of like getting a total random box of Legos and having to make a replica of the USS Ronald Regan aircraft carrier.  Sure, you can do it, but it’s going to take alot of effort.  Oh and BTW, you have to make it float when you are done. I think there is a large group like me who just wish to put something together from a kit, and then customize from there.

IMG_1196

300 foot tower with ham antennas installed by the author

So now, fast-forward to 2015.  A technology called DMR is really taking off.  Several of my HAM friends are enlisting my help to bring these repeaters live on IP networks and putting them on towers.  After awhile it really clocks with me.  This is kind of like the days of the USR Total Control modem banks.  You have a piece of hardware that does radio to IP conversion along with a few other functions. It communicates with a server over the IP network and an antenna on a tower. DMR is a standard and has set guidelines on how it is supposed to function.  You aren’t inventing the wheel, but optimizing a setup within the bounds of what the repeater is supposed to do.  To me this is a big draw. You have a baseline of how it’s supposed to work, which takes much of the frustration away which can be a very demotivating factor in any endeavor.

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Tower works on a WISP/Repeater tower

There are guys out there who are intrigued and love the RF side of stuff.  It is a science, but you can get so bogged down in it.  If you are making your own antennas you have to make sure all your wire lengths are just right, you use the correct solder, and all these 1000 other factors.  To me, that is not fun.  I admire these folks. It’s not that I want to put in the effort, I am missing the gene that experiences great joy in seeing an antenna I worked 2 months on finally go up in the air and kinda work.  I say kinda work, because I see time and time again having to adjust this or that or replacing this filter, or that connector.  To me that is frustrating. I like spending my time starting with a baseline setup and making that perform the best it can. Some say thats taking what someone else has already put together.  Heck yeah it is.  That is why I admire the tinkerer folks.  They give the folks like me a solid product i can go out and put to use because I didn’t spend those two months doing that piece of it.

IMG_0139

Tytera DMR radio

I know many folks are seeing DMR as the hot and sexy new technology.  I am looking at it as something that is able to be duplicated over and over with minor tweaks.  This keeps things interesting, without having to start from scratch each time.  Instead of focusing on soldering, and programming PLC boards, you can now focus on site installation, and tuning new and existing installations.   On the radio side you have the draw of programming radios to work with repeaters, and talk groups, and the like.  Repeaters have their own software to learn.  Again, you aren’t re-inventing the wheel, rather learning a system.  Within this system you can find ways to do things better, push the boundaries, and be involved in finding bugs and software suggestions.

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Installing antennas for w9smj repeaters

Many other HAMS tell me since I am a network guy I should love packet radio and technologies similar to that.  Not really, I have that in the interconnected networks called the Internet.  More and more effort is being focused on making connections hardened and resilient that packet radio is more nostalgia to me than anything.  We were doing such things with 300 baud modems in 1987.  Maybe, at one point I will dip my toe into such things.  But, it will have to be in a way that is an add on to existing systems, not starting from scratch.  I would have to have a “packet radio kit” that I assemble and hook into something. the CBRIDGE software that DMR uses really started my wheels turning.  It was not radio related, but it was a piece that I could wrap my head around.  For those of you who don’t know, CBRIDGE is what allows the DMR repeaters to talk over the IP network.  So by learning that piece, it motivated me to learn about DMR in general.  One day my mind said “hey you can use this and not be frustrated because sunspots knock it out for a week at a time.”

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w9smj antenna on a water tower install

So, my advice for anyone looking at HAM radio who is not a tinkering type of person take a look at some of the other aspects of the hobby.  Things like DMR are “easy” to get into in relative terms.  You aren’t going out and buying a base unit, amplifiers, hardline, and spending hours tuning it all.  After you pass your test you can be up and running very quickly without soldering a single connection.  As technology evolves and is incorporated into the hobby, it opens up a new way to get folks like myself interested.

73
kd9emp