Resource Library

Subnetting is a complicated topic that has confused students for a very long time. However, subnetting is an important topic for many different certifications with various vendors, including Cisco. In the real world environment, people are used to just punching in the numbers in many of the free subnet calculators that are readily available on the internet. For exam purposes, you still have to do this in a very fast manner since many exams are time-based and you don't have the luxury of spending those precious minutes on any single question. This Cisco training whitepaper will solve some of those age-old and complicated subnetting puzzles.

You may have noticed that it’s the dynamic routing protocols that get all the glory. Since I like rooting (routing?) for the underdog, let’s talk about static routes! As you may recall, a router has three methods for learning a route. A route can appear in the routi...

Instructor John Harmon explains subnetting using binary numbers and decimal conversions.

Instructor John Harmon continues his explanation of subnetting by showing how subnet masks can be used to sub-divide networks.

In the digital age, people and intellectual property have supplanted physical assets as the most important criteria for determining the value of an organization. It is the employees who develop the next big product or improve the practices, processes, services and internal culture that add significant value to an organization.

This short example illustrates basic VLAN operation. Examining VLANs in a large-scale installation can show the full benefits of VLANs. Consider that this is a small portion of a large corporate headquarters with 5,000 devices connected in a 20 building campus.

Switches play a vital role in moving data from one device to another. Specifically, switches greatly improve network performance, compared to hubs, by providing dedicated bandwidth to each end device, supporting full-duplex connectivity, utilizing the MAC address table to make forwarding decisions, and utilizing ASICs and CAM tables to increase the rate at which frames can be processed.

As IT departments struggle with skills gaps and businesses attempt to recovery economically from the COVID-19 pandemic, these 10 IT skills are essential to drive success. Job roles in these areas pay well, but decision-makers are struggling to find qualified candidates. If you’re looking to make an IT skills investment or start a new career path this year, these are the areas to consider.

Like it or not, Internet of Things (IoT) is upon us. There are a number of factors that will impact its adoption rate, and the inevitable privacy (or lack of) discussions will likely happen sooner than later. This is going to change the world as we know it, in many cases for the better. But we will need to keep an eye on the extent to which it invades our personal lives if it is going to be the positive force it has the potential to be.

Global Knowledge subject matter experts predict the top trends for 2020 in IT training, Microsoft, Cisco, AWS, cybersecurity and more.

Global Knowledge Product Manager Tori Easterly discusses the benefits of our Understanding Networking Fundamentals course.

One of the many useful features of tunneling is to carry non-IP traffic across an IP network, and this is still the case when dealing with IPv6 traffic. This transition mechanism makes use of a configured tunnel to transport IPv6 over a native IPv4 network, which may consist of two sites or more. Unlike the previous transition mechanisms, tunneling is not monolithic; while the basic principles may be similar, the operations are different. The following chart gives a breakdown of the current, major tunneling types in use, particularly in a Cisco environment:

When properly utilized, VLANs and trunks provide flexibility, stability and ease of troubleshooting. This paper provides technical details about VLANs and trunks, along with design options at a basic to intermediate level. Recommendations and commands are included throughout.

Thinking about getting ITIL certified? In this post, we cover the value of each ITIL certification and dive into survey results to determine whether ITIL certifications are worth it. The results are in!

Software-defined networking (SDN) is a solution that will enable your organization to meet the demands of network programmability and automation. The result will be greater network agility to support new applications while complying with increasing security needs.

The key difference between hubs, switches and bridges is that hubs operate at Layer 1 of the OSI model, while bridges and switches work with MAC addresses at Layer 2 of the OSI model.

That depends on their configurations. For example: While it makes very good sense to include redundant physical links in a network, connecting switches in loops, without taking the appropriate measures, will cause havoc on a network. Without the correct measures, a switch floods broadcast frames out all of its ports, causing serious problems for the network devices. The main problem is a broadcast storm where broadcast frames are flooded through every switch until all available bandwidth is used and all network devices have more inbound frames than they can process.

Now that the network is installed, each switch has a bridge ID number, and the root switch has been elected, the next step is for each switch to perform a calculation to determine the best link to the root switch. Each switch will do this by comparing the path cost for each link based on the speed. For paths that go through one or more other switches, the link costs are added. The switch compares this aggregate value to the other link costs to determine the best path to the root switch.

Learn about the five types of area networks.

Multiplexing is the technology that is able to combine multiple communication signals together in order for them to traverse an otherwise single signal communication medium simultaneously. Multiplexing can be applied to both analog and digital signals. A benefit of using multiplexing, or muxing, is reducing the physical hardware cost for expensive dedicated network communication segments, such as copper or fiber cables.

The most obvious difference is that hubs operate at Layer 1 of the OSI model while bridges and switches work with MAC addresses at Layer 2 of the OSI model. Hubs are really just multi-port repeaters. They ignore the content of an Ethernet frame and simply resend every frame they receive out every interface on the hub. The challenge is that the Ethernet frames will show up at every device attached to a hub instead of just the intended destination (a security gap), and inbound frames often collide with outbound frames (a performance issue).

“Twisted Pair” is another way to identify a network cabling solution that’s also called Unshielded Twisted Pair (UTP) and was invented by Alexander Graham Bell in 1881. Indoor business telephone applications use them in 25-pair bundles. In homes, they were down to four wires, but in networking we use them in 8-wire cables. By twisting the pairs at different rates (twists per foot), cable manufacturers can reduce the electromagnetic pulses coming from the cable while improving the cable’s ability to reject common electronic noise from the environment.

Good question! There are lots of networks, so I’m sorry to say that it depends. Let me explain. The smallest computer-based networks are usually PANs or Personal Area Networks. They can connect a wireless keyboard, mouse, or other devices to a computer. You may find them wirelessly linking a printer to your computer. You may have noticed these all include wireless connections. A PAN most often uses wireless technologies like infrared and Bluetooth, so it is really a WPAN (Wireless Personal Area Network).

CompTIA has raised the bar for Network+ candidates. The new certification exam has significant changes to the five "domains" or knowledge areas with new content related to security, cloud, data-center and operational concerns and troubleshooting. There is also a greater emphasis on wireless networking and VoIP. Use this white paper to help you gain an overview of what's new and what's different.

Answer? When it is flagged as a retransmission in Wireshark!

I recently responded to a message on LinkedIn from a regular reader of this blog. He asked several questions which I will answer over the course of several posts. As part of his first question, he described a strategy report that his group is producing. The audience for this strategy report considers ITIL important to the future of their business, and so he must describe which ITIL processes his data center operations group works most closely with.

Are you at a crossroads professionally or looking to start training for a new job? If so, you might want to consider pursuing network administration as a career. Network administrators are responsible for maintaining computer hardware and software systems that make up a computer network, including maintaining and monitoring active data networks, converged infrastructure networks, and related network equipment.

There are several Wireless LAN Standards, including b, g, and n, which exist in the 2.4 GHz band. These standards need around 20 MHz of radio frequency in order to transmit their signals. In this video, Ben Miller discusses how to pick access points and channels for optimal performance.