Modem vs. Router

 Modem vs. Router

In the small office or home office there is something that may be called both a modem and a router. This blog post aims to demystify both terms. Starting out the modem is a part of the wireless router that uses a technology from your Internet Service Provider (ISP) to convert analog and digital signals into a way for you to connect to the Internet. The router part is something that is using the wireless signals to manage the connected devices and route them to the Internet or locally.

The Modem

Think of the modem as a direct connection to the Internet through the ISP. The modem is something like a translator of analog signals and digital signals. Modems are using a modulator and demodulator to convert analog signals from the ISP into digital signals that can be used to get the traffic flowing. There are some models of modems that are integrated into the newer wireless routers.

There is a limit on the modem usually where there is only one output connection. This is something that limits the technology, which is why there are more switch ports on a wireless router. It acts as the modem and a router which enables wireless and wired connections through the interfaces on a wireless router. This limit is something that will not allow most people to access the Internet with multiple devices.

The Router

The router component connects the modem to essentially create a Small Office Home Office (SOHO) network. This uses the wired and wireless signals to route traffic to its destination, on the Internet or locally. Most people have more than one device so a router acts as a traffic cop and gets data to go to where it is needed. This typically has the capability to route the traffic but not connect to the Internet.

The router is something that connects your movies to play on the device that you are using through the SOHO network. It also works to send Wi-Fi signals to the right device and does basic network security keeping you safe from hackers. This is far from the safety of a firewall used by enterprises but does keep you somewhat safe from amateur hackers.

The Gateway

The gateway is a device that merges the capability of the modem and the router along with switch ports to have a single device managing the network. Internal to the gateway the devices are still acting as separate components to do the job that is needed to connect your network to the local network or the Internet. The gateway acts as a modem and a router connecting to each other in one single system like the newer models that have come out. Gateways are the future of where the technology is going.

Conclusion

The devices that you connect to a stand-alone modem, and a router use a certain order that you would need to troubleshoot if you are getting a bad signal or poor quality. This usually means that one or more of the devices is overheating and needs to cool down. The modem should be first and then the router should be turned back on after the modem. Usually, you would need to reset them by pressing the power button on each for at least 60 seconds to do a soft reset.

Being an IT Professional, there are times when a gateway may overheat, this might be a fan issue with the device and can be replaced with a newer one from most ISPs. Usually, they will swap the old one for a new one and you can get better performance if the device is replaced after 3 to 4 years of use. Try to be smart and look up the replacement policy from your ISP. Take a look at any electronics retailer and look up different models of modems, routers and gateways to see the differences between them.

Networking 101 - Introduction to Computer Networking

Introduction

Computer networking is complex and full of acronyms that you might have been wondering about. This guide goes over understanding these concepts so you can learn these acronyms. Breaking these down into easy to grasp concepts will help you on your journey towards mastery. These acronyms are something to learn if you want to go for your Network+ or CCNA certification or just general knowledge if you are interested in cybersecurity.

Hardware

Switches, routers, wireless, Ethernet, and fiber are the core hardware concepts that you would need to grasp for these certifications. Switches act as a switchboard and function like the old phone operator. These switches have a place within a Local Area Network (LAN) and act as something like the local operator or an intercom system.

Routers are essential for routing packets through what is called a Wide Area Network (WAN). The routers operate more like the postal system and essentially mail the packages (packets) to another city. Routers operate at layer three of the OSI Model and are packet switching controls that allow for a packet to be routed.

Wireless or Wi-fi acts as a medium that is more convenient than Ethernet which is used more for stability. Wireless is sometimes used in locations that would be harder for a cable to reach every connection. This would be like in a Cafe or a hotel lobby. Wireless and Ethernet are not the only medium used. Fiber acts as a medium over light on the individual glass fibers that uses lasers to transmit and receive.

Addressing

Internet Protocol (IP) addresses are used as a temporary or assigned address. This is used somewhat like your mailing address and can be assigned by DHCP. Media Access Control (MAC) addresses are essentially physical addresses that are more like a fingerprint of the Network Interface Card (NIC).

Packets are the network encapsulation for data transfer between devices and operate on the network layer of the OSI model. Data travels across the network through different mediums and allow for the encapsulating and de-encapsulating of packets going up and down the OSI Model layers.

Data is the layer for layer five through seven, then segments which are layer four using the IP address and port number to make a segment. The data going down is encapsulated with a layer three header as a packet and then frames for the layer two header and footer along the way through to layer one which is the physical layer.

Services

The main services that are in computer networking include DNS, DHCP, TCP/IP, and UDP. Domain Name System (DNS) translates human readable names into IP Addresses. This acts as a phonebook of sorts for the internet. Dynamic Host Configuration Protocol (DHCP) allows devices to be automatically assigned to an IP address and acts as a leasing service for IP addressing on an as needed basis.

Transmission Control Protocol (TCP) works with IP in order to send connection-oriented transmission of packets which are reliable as opposed to User Datagram Protocol (UDP) which is connection-less and unreliable. This is more for video and voice which doesn’t require all of the data and can use UDP.

Conclusion

Essentially all of the computer networking topics revolve around hardware, addressing, and services. These acronyms are something to keep in the back of your mind as you progress through your IT career. You made it through the acronyms; you should try out some commands on a Windows or Linux computer.

Try pinging 8.8.8.8 and see what you find that will help improve your knowledge. Note that pinging on a Linux computer will require a ctrl + c to break it. For the 8.8.8.8 address this is a main Google DNS server that is known. Take note of what happens when the ping is successful and when it is not.

Changing the Focus of the Blog

 Changing the Focus of the Blog

I am doing something new on this blog and changing up the way that I am using it. There are some things that didn’t resonate as well for me doing the Information Technology blog focus. The focus of this blog will now be Introductory Computer Networking. This will cover the CCST Networking, Network+ and CCNA topics.  Additionally, I will be doing some Information Technology Concepts as it relates to Introductory Computer Networking.

Some of the things that I am doing for my specialty now includes computer networking. I am interested more in AI, Cloud, and Design for networking and will be incorporating some Juniper certifications in my content on this blog in the future. I do not have the Network+ but will cover it as I have the CCNA and two CCST certifications. The second CCST is the cybersecurity one.

Blogging

The thing that I am good at for content writing is blog posts. I have been blogging since 2022 when I started the aaronwdejong.net blog as a journal blog. Earlier this year, I started doing aaron597.com and this blog aarononit.blogspot.com expanding to the three main blogs that I have. I do have plans to do another newsletter, and you can go to aaronwdejong.net and sign-up for the newsletter.

My blogs currently are these three and I will be doing different aspects of Computer Networking. The aaronwdejong.net blog will be more about my journey in IT with my ultimate goal of becoming a CTO, CISO or CIO. On the aaron597.com blog, I will be changing up the focus to being more focused on different areas of computer networking. That blog is more about Cloud Networking, Network Security and some more advanced concepts like SD-WAN and VXLANs.

Conclusion

These changes reflect the specialization in computer networking with my focus more on AI, Cloud, and Design. I have recently made a mind map that describes what certifications I am wanting to do for each of these areas and does involve more Juniper, Cisco, and Microsoft certifications among others. The certifications still include the CISSP and the PMI-ACP among the computer networking certifications.

I am still planning on doing the CAPM and will be doing the AB-900 and the JNCIA-Junos certification this year. I have another year and a half before I need to re-certify my CCNA. Working on these specialties has made me more like a CIO in my approach, so that will most likely be a focus going forward out of the CISO, CTO and CIO decision. The networking path that results in a C-Suite role would be more likely to be the CIO instead of a more specialized role as a CISO or more of a technology application development role for a CTO.

Linux Kernel

Linux Hardware and Software Layers

There are four main layers with Linux which are monolithic and are tied into the one system. The base layer is the hardware which can talk through the kernel, using it to interact through drivers for the software to function. The next layer is the kernel which acts as a bridge between the hardware and the software.

The next layer of this Linux hardware and software stack is the Shell which is normally Bash. This is where the Command Line Interface (CLI) commands are used and talk through to the kernel to manage the hardware. The top layer is the user interface where the user uses the Graphical User Interface (GUI) for things like web browsers and text editors.

Linux is Monolithic

The way that Linux is monolithic is tied to its architecture. This architecture is designed to have all core services run together as a group in a Kernel Space. This Kernel Space is something that is a privileged and highly secure area of memory. This design is making Linux fast and efficient based on lower delays between core services.

The other type of kernel is called the Microkernel which uses a user space on certain operating systems like Minix 3 or the Apple IOS which uses XNU that is more of a hybrid kernel. X not Unix (XNU) is a specialized hybrid monolithic and microkernel that is used by Apple to provide the benefits of both types of kernels.

Four Main Jobs of the Kernel

These are managing device drivers, system calls, process management, and memory management. Device drivers are the actual assembly code for each of the items of hardware that talk between the hardware and the kernel. System calls are the actual requests from software to specific hardware for things like writing data to the disk.

Process management is where the kernel decides what process gets run and how long it can be in the CPU. The memory management function of a kernel is where the kernel decides how much RAM and for how long it stays in memory. The kernel has more functions like preventing and mitigating conflicts in processes and acting like a superuser to manage security and resources needed to perform tasks.

Conclusion

The kernel is a concept that doesn’t get talked about enough. This concept of a kernel is the essence of Linux which in reality is more a kernel than an operating system. You can get more in depth into this topic by including them in your studies. Studying has saved me more time on certification exams and will be something that will allow me to remain consistent. Study well guys and be a lifelong learner.

Information Technology Roadmap

Information Technology Roadmap

There are some aspects of information technology that are more relevant for building a career roadmap. Depending on how you want to go about it you can tailor your roadmap to the IT career that you want to be in. This roadmap will help guide you in your career. When setting up a roadmap there are things that you will want to do like getting a broad IT skill set that will help you in your career.

Roadmap

The way that I went about it was to do the CompTIA ITF+ and then the A+ was next. The things that I was doing would correlate with the Tech+ and the current version of the CompTIA A+ exam. I would also recommend putting in at least one cloud certification like the AWS Certified Cloud Practitioner or the AZ-900.

I did this to understand more about the underlying technology in hardware and software components of PCs. This has helped develop more skills as I now hold ten certifications in IT. The path that I am taking was thought out more along the fundamental pathways for Azure, AWS, Linux, and Cisco certifications.

My Own Roadmap

I want to be able to help guide your journey and allow you to see how I am going about my own roadmap. You don’t necessarily need to have ten certifications, but you would need both skills and certifications. The reason that I am going about doing these certifications is so that I can tailor my roadmap more towards a CIO, CTO or CISO job role which is something that would need deep technical knowledge.

One of the things that I am doing is focusing more on the Cisco and Microsoft technologies before other certification paths. This will be something that can help with Cloud Networking and Network Security which are two of the subjects that I am pursuing. Later on I might do Network Forensics but want to save that for future studies.

Building Your Roadmap

For your own roadmap, I would recommend that you start with the fundamentals and get a wider view of Information Technology. This should be before you decide what skills and certifications you would need to have on your own roadmap. Going broadly in IT has helped my own business as I can do more roles as needed and understand the technical side of my content writing business.

Conclusion

Giving something back is what the next part of my journey is about. This advice to tailor your own career by tailoring your roadmap will help in your career journey and future in IT. By taking the time to understand and plan what you want to do with your career you can gather the skills and certifications needed for your career.

History of Linux and FOSS

 History of Linux

For the history of Linux, it is best to understand more about Unix. Unix was made in 1969 by Bell Labs by Ken Thompson and Dennis Ritchie. It was intended to be a multi-user system and was rewritten with C in 1973 for portability. Unix was released to the public by Bell Labs with Version 6 in 1975 for general use. 

In 1983, Robert Stallman created the GNU Project to create a free Unix- like system which is something that Linux eventually evolved from. Linus Torvalds started Linux as a personal hobby project back in 1991. This was a similar model to the GNU Project and was licensed under the GNU General Public License.

In 1992, the GNU Project and the Linux Kernel were merged under the GNU GPL which allowed for an open-source version of Linux. There are different distributions that came out like Debian and Slackware in 1993 allowing for more distributions and flavors later on. There are three main distributions today that most Linux systems are derived from. They include Debian, Red Hat and Arch Linux mainly, which are where the different flavors originate from.

History of FOSS

FOSS is something that grew out of the general cooperation of building software in the 1960’s and 1970’s. It was built on the concept of free software which Robert Stallman’s GNU Project and Free Software Foundation helped with the development of Free and Open-Source Software later on using Linux and other distributions. The Free Software Foundation was made in 1985 by Robert Stallman.

In 1998, the term open-source was coined by the Open-Source Initiative which helped the development of different companies and organizations contributing to other open-source projects in the corporate world. This is something that is happening still today. Linux is used heavily in web servers, cloud computing and in mobile devices like Android.

Knowledge Byte

The history of Linux is something that I have studied for in college and also when studying for the LPI Linux Essentials certification that I have. There are some ways to study for the Linux Essentials which include a study plan, having three or more resources and also keeping a schedule of each section that you have selected for your study sessions. It is also good practice to eat healthier and get enough sleep, so you are not having issues with energy or your mental health.

Conclusion

These are some of the events that contributed to Linux and FOSS. There are companies that continue to contribute to open-source projects like Git and Apache Server. The development of more distributions and flavors is getting Linux to be a more portable operating system than Windows. Linux is now used to power corporate systems and supercomputers along with embedded systems.

OSI Model vs. TCP/IP Model

 The OSI Model (Open Systems Interconnection) is essentially a reference model that helps IT technicians understand the different layers. For the TCP/IP Model, this is the Transmission Control Protocol/ Internet Protocol that is a functional model and is how the layers actually work. There are seven OSI layers compared to the four TCP/IP layers. The OSI model was made by the International Organization for Standardization as a conceptual model.

OSI Model

The best way to think about the OSI Model is to break it down into layers. These are from the bottom to the top and starts with layer 1 which is the Physical layer, layer two is the Data Link layer, the Network layer, Transport layer, Session, Presentation and layer 7 which is the Application layer. By using the Please Do Not Throw Sausage Pizza Away mnemonic you can remember these layers.

The Physical layer is the actual hardware, cabling, and wireless mediums and uses encapsulation to go to the Data Link layer which are frames. The Network layer uses packets and encapsulates the frames into packets. By the fourth layer, the Transport layer, the packets are encapsulated by ports.

With the Session layer, the ports are encapsulated by sessions which interact with layer six to allow for encryption and then the Application layer which is by that point data. By understanding these layers, you can understand more about what the TCP/IP Model is about and why it is easier to troubleshoot with the OSI model. The OSI model is also used by vendors that create hardware and software to be interoperable.

TCP/IP Model

In the TCP/IP Model there are four layers which are the Network Access layer that corresponds to Layer 1 and 2 of the OSI Model, the Internet layer for Layer 3, Transport layer for layer 4, and the Application layer which corresponds with layers 5, 6, and 7 of the OSI Model. This model was developed by the Department of Defense and is a practical standard for internet communications.

Conclusion

By learning more about the OSI and TCP/IP models you can understand how to troubleshoot more effectively. There are some encapsulation and decapsulation items going up and down the TCP/IP stack at the same time. This allows for effective communication across systems. When you understand this at a deeper level you can go for more advanced certifications like the CCNP or even the CCNA.