CWNA

CWNAI am currently reading the Certified Wireless Network Administrator book 4th Edition by the CWNP group and Sybex. It is the Official Study Guide for the CWNA-106 exam. Hopefully it will be more pertinent than the book I purchased for the CCNA Wireless Exam. I really liked the information in the Cisco Book but you really had to augment the information with hands on lab experience as well as memorizing the types of questions on the exam and focusing on online Cisco resources and forums to learn the balance of information. I think that was good on the whole because it pushed me back into the material so that I would continue learning. I am still working on the third chapter. Much of the first part of the book is review. What I like about the review is that it treats the information from another person or group of peoples perspective. The Cisco waves on a rope analogy is pretty crude. I am fortunate in that I have been studying waveforms and have had access to Oscilloscopes and service monitors since I was in grade school.

Some of the good information that I have gleaned from it so far are that the ISO standandards are named from the Greek work isos or iσoϛ. This basically means equal or same. The group itself is named the Internal Organization for Standardization. Makes more sense now. It would be IOS if they used the name or possibly IOFS. Honestly how many more versions of IOS do we need?

I have learned an interesting fact about where the term decibel comes from. Decibels are relative units of measurement. They were originally created by Bell Labs. The unit of measure describes the difference in power of 10 to 1. This unit is a bel. Each 10 to 1 difference in signal amplitude is 1 bel. They further broke the unit into 10 pieces referred to as decibels. 1 bel = 10 decibels. The decibel allows very large differences in signal to be expressed using small easy to use values.

Getting ESXi Running

Today I decided that my home lab needs to have an ESXi server. I have decided to call it SAMI in honor of the people of the Northern European Arctic. I have installed it on an old dell PC Optiplex 740. I made an ISO image CD and loaded it that way. I could not find a USB stick to Rufus a boot USB otherwise I would have preferred that method. The installation kept complaining about my hardware. I pushed on through. I did not want to leave a DHCP address on it so I went into the setup with keyboard and monitor on boot and assigned a static IP.

I navigated in my browser to the IP and downloaded the Vsphere client software. I had not installed it on my home machine yet.

General Info

I have downloaded Ubuntu 15.04 and am running through the install. I created a datastore on the ESXi server and then uploaded it through the Vsphere client. You have to tie the ISO in the data store to the CD/DVD drive on settings as well as check the connect check box and connect at startup.

One frustrating part of the installation is that you need to see the Continue button. I have tried tabbing around. On one screen it was not tabbing. I found alt+F7 keys allows you to move the installer windows around in the little console window.

Don’t forget to remove the datastore ISO image from the Virtual CD/DVD drive. I un-check connect and un-check connected at power on. Restart Ubuntu.

I had a lot of graphics problems initially. I have used the display settings before but could not get the apply checked.

I ended up using the following terminal command.

xrandr --output Virtual1 --mode 1024x768 --rate 60

I then need to setup SSH for remote access.

sudo apt install openssh-client

sudo apt install openssh-server

Time to script.

MommyLink

My First WiFi Project

It is hard to believe that there was a time in my life when I did not have WiFi connectivity. When I was in high school we were so lucky to have dial-up internet access. I could surf at 20-30 Kbps. It was during this time that my mother was diagnosed with Alzheimer’s Disease. It wasn’t until I was in college that she reached a point where she needed to have a degree of supervision while she was at home. In the way that a hammer sees ever problem as a nail, I ended up deciding that the best way to watch her would be to install a network camera at home. Network cameras were just hitting the market place. Panasonic made a KX-HCM10 camera. The resolution was not great but it still offered pan and tilt which was very good for the price point at the time.

I used SMC WiFi radios running 802.11b. I ran a 2″ PVC conduit from the house to a small tower along the fence in the field. I had a stainless steel box with 120 VAC and CAT 5 running back to the house.

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I installed a hop on a DC powered site on Racehorse Mountain. I had to install a voltage regulator as the 12 VDC site needed to be converted to 5VDC for the radios. I used a cross over cable between the radios as I did not want to power an additional device.

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Fortunately I was able to see both sites from the ice guide bridge on Squalicum Mountain. I installed a small switch as having connectivity on this site was advantageous.

Sqlink

At Lookout Mountain I was able to tie into a T-1 Adtran Netvanta Bridge. This provided me connectivity to downtown Bellingham.

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I read back through my notes on the design. I was able to achieve a variable throughput on the link between 30-85Kbps. While this might not seem much better than dial-up, the ability to have a connection on all the time was amazing. I setup the camera in the living room. Unfortunately the video did not pass very well at such low data rates. I could see my mother but it was not the real time video I was hoping for. It is still amazing to me that this link worked at all. I did not have it in for very long. Ice on the tower on Racehorse knocked the element off the feed horn. I had built an ice shield. I did not figure that the cheap antennas I had used would last very long.

I ended up repurposing some of the equipment. Before I ran 2″ conduit and direct burial CAT5e between all the church buildings, I used one of the bridges to provide access between the church offices. I also used some of the parabolic grid antennas for DFing interference coming from the Canadian operator at 2.5 GHz when I was working for Clearwire.

Point Coordination Function

I have spent some time looking into PCF. Here is a definition from online…

Point coordination function (PCF) is a Media Access Control (MAC) technique used in IEEE 802.11 based WLANs. It resides in a point coordinator also known as Access Point (AP), to coordinate the communication within the network. The AP waits for PIFS duration rather than DIFS duration to grasp the channel. 19-78 μs.

Apparently PCF has rarely been implemented by any vendors.

disapoint

CCNA Wireless 200-355 Test Version 1.0

This afternoon I took the WIFUND exam. I was disappointed that the CCNA Wireless 200-355 Official Cert Guide 1st Edition by David Hucaby only helped with about 40% of the questions. I am beginning to understand that with Cisco testing, it is more about taking the test enough times to know what the content is going to be over trying to buy the correct books and memorizing and understanding the topics in the book.

I scored 743 out of 1000 on my first try. The passing score was 860.

RF Fundamentals 75%
802.11 Technology Fundamentals 63%
Implementing a Wireless Network 70%
Operating a Wireless Network 62%
Configuration of Client Connectivity 18%
Performing Client Connectivity Troubleshooting 50%
Site Survey Process 86%

Now I know the areas I will need to study before my next attempt.