Learning, certifications and the xISP

One of the most asked questions which comes up in the xISP world is “How do I learn this stuff?”.   Depending on who you ask this could be a lengthy answer or a simple one sentence answer.  Before we answer the question, let’s dive into why the answer is complicated.

In many enterprise environments, there is usually pretty standard deployment of networking hardware.  Typically this is from a certain vendor.  There are many factors involved. in why this is.  The first is total Cost of Ownership (TCO).  It almost always costs less to support one product than to support multiples.  Things like staff training are usually a big factor.  If you are running Cisco it’s cheaper to train and keep updated on just Cisco rather than Cisco and another vendor.

Another factor involved is economies of scale.  Buying all your gear from a certain vendor allows you to leverage buying power. Quantity discounts in other words.  You can commit to buying product over time or all at once.

So, to answer this question in simple terms.  If your network runs Mikrotik, go to a Mikrotik training course.  If you run Ubiquiti go to a Ubiquiti training class.

Now that the simple question has been answered, let’s move on to the complicated, and typically the real world answer and scenario.  Many of our xISP clients have gear from several vendors deployed.  They may have several different kinds of Wireless systems, a switch solution, a router solution, and different pieces in-between.  So where does a person start?

We recommend the following path. You can tweak this a little based on your learning style, skill level, and the gear you want to learn.

1.Start with the Cisco Certified Network Associate (CCNA) certification in Routing and Switching (R&S).  There are a ton of ways to study for this certification.   There are Bootcamps (not a huge fan of these for learning), iPhone and Android Apps (again these are more focused on getting the cert), online, books, and even youtube videos. Through the process of studying for this certification, you will learn many things which will carry over to any vendor.  Things like subnetting, differences between broadcast and collision domains, and even some IPV6 in the newest tracks.  During the course of studying you will learn, and then reinforce that through practice tests and such.  Don’t necessarily focus on the goal of passing the test, focus on the content of the material.  I used to work with a guy who went into every test with the goal of passing at 100%.  This meant he had to know the material. CompTIA is a side path to the Cisco CCNA.  For reasons explained later, COMPTIA Network+ doesn’t necessarily work into my plan, especially when it comes to #3. I would recommend COMPTIA if you have never taken a certification test before.

2.Once you have the CCNA under your belt, take a course in a vendor you will be working the most with.  At the end of this article, I am going to add links to some of the popular vendor certifications and then 3rd party folks who teach classes. One of the advantages of a 3rd party teacher is they are able to apply this to your real world needs. If you are running Mikrotik, take a class in that. Let the certification be a by-product of that class.

3.Once you have completed #1 and #2 under your belt go back to Cisco for their Cisco Certifed Design Associate (CCDA). This is a very crucial step those on a learning path overlook.  Think of your networking knowledge as your end goal is to be able to build a house.  Steps one and two have given you general knowledge, you can now use tools, do some basic configuration.  But you can’t build a house without knowing what is involved in designing foundations,  what materials you need to use, how to compact the soil, etc.  Network design is no different. These are not things you can read in a manual on how to use the tool.  They also are not tool specific.   Some of the things in the Cisco CCDA will be specific to Cisco, but overall it is a general learning track.  Just follow my philosophy in relationship to #1. Focus on the material.

Once you have all of this under your belt look into pulling in pieces of other knowledge. Understanding what is going on is a key to your success.  If you understand what goes on with an IP packet, learning tools like Wireshark will be easier.  As you progress let things grow organically from this point.  Adding equipment in from a Vendor? Update your knowledge or press the new vendor for training options.  Branch out into some other areas ,such as security, to add to your overall understanding.

Never stop learning! Visit our online store for links to recommend books and products.

WISP Based Traning Folks.
These companies and individuals provide WISP based training. Some of it is vendor focused. Some are not.  My advice is to ask questions. See if they are a fit for what your goals are.
-Connectivity Engineer
Butch Evans
Dennis Burgess
Rickey Frey
Steve Discher
Baltic Networks

Vendor Certification Pages
Ubiquiti
Mikrotik
Cisco
Juniper
CWNA
CompTIA

If you provide training let me know and I will add you to this list.

Bitlomat announces Passport

From the Bitlomat Page:
Bitlomat has developed Passport, an innovative point-to-multipoint TDM-derived protocol with the needs of large scale outdoor networks and wireless internet service providers (WISPs) in mind.

Passport resolves the hidden terminal issue that is the root cause of poor performance in many large scale wireless networks, and provides the network operator with the highest throughput and spectrum efficiency available on the market.

Passport implements an advanced medium access control protocol to allow for fine-grain configuration of the guaranteed bandwidth that each client should have in the network. A WISP can create different classes of traffic and users, providing different guaranteed throughput on the same wireless network based on the access level or SLA that each user has subscribed to.

Passport is available for free for all Bitlomat products and comes embedded in the Bitlomat firmare.
Read More here..

The news that really makes you want to check it out:
Not only does Passport offer major improvements in throughput, bandwidth, latency, etc. but it’s now available for download to be flashed on to your existing network!
Read More here..
http://bitlomat.com/affiliate-area/

Bitlomat Photos

Some of you have been asking for some photos of the Bitlomat CPE in real life.

The last photo is side by side compared to a UBNT M5 Nano

Capacity of a UBNT AP vs the number of clients

Almost all the time I get asked: “How many clients can an AP handle?” . My answer is always a very long and drawn out one. There is no set in stone answer. There are many factors which can affect this. I will go into some of these and then explain how to calculate this.

Some things that we will assume.
1.You are calculating on an 802.11N Ap with some kind of polling (TDMA, NSTREME, AIRMAX, etc)
2.You know the MCS values and/or data rates at channel widths.
3.When I say in an ideal situation I mean basically in the lab. This is our baseline. This means no outside noise, everything is working properly, and all the connected clients are excellent.

Before I get into what affects how many clients can an AP handle we need to shift our thinking a little. We don’t think in terms of how many clients can an AP handle. We need to think in terms of how much capacity an AP has. This is very important to think in these terms. If you do so things will become more clear and more quantifiable.

So now, on to what affects the total capacity of an AP.

1.The channel width. In and ideal situation you will get more Capacity out of a 20 mhz channel than you will a 10mhz channel.
2.Noise. In the real world you will have interference. If you have interference the noise floor drops, customer signals can’t reach maximum modulation, and there are retransmits.
3.Plain old signal. Things such as trees, distance, fresnel zone, and antenna gain all affect signal
4.The speed you are giving to each customer.
5.Overselling. The concept of overselling has been around since the dial-up days. You are betting your customers are not all online at the same exact time doing the exact same stuff. So you can oversell your capacity. I will explain this a little more in a bit how this factors in.

Okay, so let’s dive into this. I am going to use a Ubiquity Rocket M5 as an example. Again, this can be applied to any polling type N radio.

Say we have a Rocket M5. At a 20MHZ channel the best modulation this M5 will do is MCS 15 at 130 Megs of over the air. What do you mean Over the Air? Well there is a difference between actual throughput and the Wireless Data Rate (aka over the air). Your actual throughput/capacity will be 1/2 of the over the air rate minus a little for overhead. I factor in 10% overhead for easy figuring.

Back to our figuring. You have 130 megs of capacity on your AP in an ideal situation on a 20 mhz channel. If we do our math:
130 / 2 = 65 Megs of Capacity to sell on the AP.
Now here comes the overselling part.
If we oversell at a 2:1 ratio we have 130 Megs of capacity on the AP.
If we oversell at a 3:1 ratio we have 195 megs of capacity on the AP.

We can do higher ratios, but it starts to become a moving target. With the spread of Netflix, Youtube, Hulu, and other streaming services the average customer is sucking down more and more bandwidth for longer periods of time. Think of a restaurant with so many tables. If your customers are staying longer and longer, you don’t have as much seating capacity to turn over for new people to sit down and consume your food. This is for another blog post.

So, let’s say we are overselling at 3:1. We have 195 megs of capacity. We now need to think about what packages we are selling to our customers. If they are all say 5 meg packages, this means we can safely sell 39 connections to the AP. 195 / 5 = 39. You can figure up the math if you have 3 Meg, 10 meg, or a mixture.

Now to the real world (aka why do my customers hate me and my AP sucks?).

The following is a real AP in the wild.  Blacked out to protect the innocent from script kiddies.

ubnt-main-screen
Couple of things to Note (circled in Red).

20 MHZ Channel
Capacity at 45% . This is more important than anything, even CCQ.
43 clients associated.

Let’s apply our math we learned earlier. We know a 20 mhz channel nets us MCS15 – 130 Megs

Here is the kicker.  Our capacity is at 45%.  This means we only have 45% of 130 megs of Over the air capacity.  Take this in half (130 / 2= 65   45% of 65 = 29.25.
This means all 43 of these customers are sharing 29 megs of capacity on the AP.  And the quality isn’t the greatest (37%).  So this means there are retransmissions going on between the client and the AP. The client can’t talk as fast as it is capable of in most cases. This means you can’t oversell the AP as much due to the quality of the signals being poor.  It is important to note I am talking about the quality and capacity of the signals, not signal strengths.

If those 43 people are all paying for, let’s say, 2 Megs download.  That means your AP needs to support a minimum of 86 megs. Thats without overselling.  We only have 29 megs in the current state!

We need to get those capacity numbers up.  How do we do that?

1. Channel selection. A noisy channel will drag everyone down.

2. Antenna gain.  This can be done at both the client and the AP.  A higher gain or better quality antenna can cause the clients to “hear” better.  You might not get an increase in signal strengths, but you are looking for an increase in quality. I use a loudspeaker metaphor.  You can hear a loudspeaker from a far distance, but you might not always be able to make out what is being said.  If you can somehow make out what is being said more clearly, then you don’t have to have the speaker turn up the volume.

3. Shielding. This helps eliminate the amount of stuff a client or AP hears.

4. Channel Width.  Sometimes dropping the channel width down can increase signals, thus raising the overall capacity.  Keep in mind it will lessen the overall capacity of the AP.

5.Simply getting rid of customers that shouldn’t be installed.  We have all done installs that were iffy.  These can drag down the overall capacity.

I hope this has helped understand.  The biggest thing I want you all to take away from this is think in terms of the amount of capacity you have to sell, not the number of connections.