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29 July 2019

Seven years ago ...

Seven years ago I was in my chair like today I do. Thinking about what I could write in my recently opened blog. I wanted to write something about networking and security but I didn’t know exactly what to write. The goal were writing because I wanted to improve the writing skill which was needed to pass the English exams at Official School of Languages. In the beginning, I wrote in Spanish because writing was a hard-working task for me. However, I ended up writing in English because it’s better for improving the writing skill in English language.

Writing is not the only skill I wanted to improve but also the reading skill to get new vocabulary. Therefore, I try to get time for reading books. For instance, I’ve been reading many books in the last year such as Factfulness, The Art of Intrusion or Inside Soviet Military Intelligence although I’ve also read the Cyber Strategy of the U.S. of America and Aprendiendo de los mejores. Actually, I really love reading and I’ve even been reading the Revue Stratégique Cyberdéfense de France.

Writing and reading are important skills to improve languages but speaking is also very important. I don't speak a lot in English language in my job, just from time to time, but I’ve had the lucky to provide Training on Networks, Systems, Hacking and Forensics in the last year where I’ve able to improve the speaking skill in my native language. I think students have learnt many interesting things such as Buffer Overflow Attacks or Fileless malware forensics. In addition, I’ve been in a high school to speak about Security on the Internet for teenagers.

I think the training courses were interesting because we’ve deployed, installed and configured many tools. For instance, we configured L7 DDoS Mitigation, CSRF Protection, XXE Protection and Bot Protection with F5 BIG-IP ASM. In addition, I’ve tested with SSO Authentication, Portal Access & Webtops, and SSO for Terminal Services with F5 BIG-IP APM. The new version 14.0 in BIG-IP added lots of features and improvements such as the new HTML5 Dashboard or the Threat Campaigns Subscription.

During the last year, the new version 6.2 in FortiOS has also been released. It’s amazing the amount of new security features have been improved. Security Fabric, SD-WAN, Inspection modes, WIFI6 are only some features improved. In addition, I’ve installed security appliances such as FortiSwitch, FortiSandbox and FortiWeb as well as I’ve configured two FortiGates in a VRRP domain.

This last year has been rewarding because I’ve also been working with networks. I’ve studied about Cisco Nexus such as vPC, FabricPath, Fabric EXtender (FEX), etc. I’ve installed Mellanox switches where I studied about RDMA over Converged Ethernet (RoCE) and Data Center Bridging (DCB). What’s more, I’ve been reading and studying about Outdoor Wireless Link to know the Fresnel zone, channel width, signal-to-noise radio (SNR), EIRP, etc.

Regards my friends. I'm delighted. It's time to rest. It's time for a holiday.

22 July 2019

Outdoor Wireless Link

I studied IT engineer in Extremadura where I had to take lots of maths subjects. I also took subjects about application development and operating systems. All of them were interesting. However, today, I’m mainly working with networking and security. I only took one subject about security, it was optional, and I also took two subjects about networking, but I think it’s enough to take the plunge to do networking and security projects because we have to keep studying day in day out. For instance, I didn’t take any subject about Wireless Links but I had to study how they work and how to configure them.

I’ve already had the luck of working on two projects about Wireless Links. One of them was to broadcast free WiFi in a small town and the other one was to connect several buildings in the middle of the countryside. Two interesting projects. These days, I’m working on a new project to connect two buildings because there is no Internet connectivity in one of them. Therefore, I have to plan an Outdoor Wireless Link where I have to take into account the distance between buildings as well as the Line of Sight (LoS), Fresnel zone, fade margin, frequency, channel width, signal-to-noise ratio (SNR), etc.

Outdoor Wireless Link

There are software which are very useful for planning outdoor wireless links such as Radio Mobile and AirLink. These software help us to choose features such as frequency, channel width, etc. For instance, we’ll have to choose a free frequency or a licensed frequency. If we want to use a free frequency in 2,4 GHz or 5 GHz, we’ll have to configure an EIRP accordingly to the country where we are going to install the wireless link. However, if we want to use a licensed frequency, we’ll have to require that license to the government.


These software also help us to know if there is Line of Sight (LoS) between sites. This is very important because LoS allow us to know if the wireless link will be successful. However, if there is no LoS, we won’t know the wireless link performance during the planning phase. For instance, if there is a partial obstruction with a mountain, there could be attenuation, reflection or refraction. It’s also important to highlight how low frequencies can propagate to great distances with little attenuation.

Line of Sight - LoS

When we are going to choose an access point to install a wireless link, we also have to take into account what is the network going to be used for because VoIP traffic has not the same network requirements than Data traffic. For instance, VoIP traffic needs 50 PPS while Video streaming traffic needs 1000 PPS.

TCP-IP Packet
To sum up, there are lots of technical features we should know before installing an outdoor wireless link. The Line of Sight, frequencies, channel width, etc should be studied carefully to install a wireless link successfully. Therefore, if we want an efficient and reliable wireless link, we’ll have to study these concepts at University or by ourselves.

Regards my friends. Drop me a line with the first thing you are thinking!
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