73 Results Found
The driver behind 802.11n is MIMO, or multiple input multiple output. This video explains how MIMO works to double your channel speed by sending two or more data streams over the same channel.
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.
Global Knowledge Product Manager Tori Easterly discusses the benefits of our Understanding Networking Fundamentals course.
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.
Authentication is one of the essential components of security. It is one part of the concept known as authentication, authorization, and accounting (AAA). Authentication is the process of claiming an identity the proving that you are that claimed identity. Authorization is the mechanism to control what you can access or do. Accounting is the recording of events into a log to review the activities against the rules and policies in order to detect violations or confirm compliance. All three of these should be addressed when constructing a system in order to have a reasonable foundation for reliable security.
Session Initiation Protocol (SIP) is an internet signaling protocol, developed by the IETF (starting in 1996), for establishing, maintaining, and tearing down sessions between a variety of real-time media, including voice, video, and chat. SIP allows endpoints to locate other endpoints, whether stationary or mobile. SIP doesn't have to worry about transporting voice or video as Real Time Transport Protocol (RTP) takes care of that. It also relies on Session Description Protocol (SDP) to negotiate capabilities and codecs. SIP does not provide a Directory Service or Authentication, but it does work with services such as LDAP or RADIUS. SIP is only concerned with signaling. This white paper is going to look at the way SIP is used in the converged Unified Communications environment.
A local area network (LAN) provides a path of communication, allowing the delivery of packets of data, voice, or video originating from the sender (logical source address) to the receiver (logical destination address). Ethernet is the most common LAN used. As you start to learn about networking, remember that communication and the movement of large numbers, whether it is people, cars, mail, or network traffic, have a commonality. Everything you know and use in your daily life can be compared to the way traffic moves.
The OSI model is a conceptual tool used to discuss and describe network functions. The use of a standard reference model is essential to communicating ideas as well as creating new technologies. It is a good idea to be familiar with the OSI model, the features assigned to each layer, and examples of common protocols or technologies associated with the OSI layers.
The OSI model is a conceptual tool used to discuss and describe network functions. The use of a standard reference model is essential to communicate ideas as well as create new technologies. It is a good idea to be familiar with the OSI model, the features assigned to each layer, and examples of common protocols or technologies associated with the OSI layers.
Diane Teare, Global Knowledge's Cisco Course Director, discusses the advantages to taking our CCNA Boot Camp.
Global Knowledge instructor Kevin Schweers reviews the fundamentals of spanning tree, including the three primary steps.
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:
As with the adoption of any new technology, the move from IP version 4 to IP version 6 will take a number of years to complete. During that transition phase, various mechanisms will be necessary to continue support of the older protocol as the newer gains widespread momentum. In addition, there has been some evolution even within the availability of these mechanisms, some of which have already passed from general use into deprecated status. Network engineering professionals already proficient in the use of IPv6, as well as the available coexistence mechanisms, will undoubtedly stay in high demand throughout this process.
The STP (Spanning Tree Protocol) standard (IEEE 802.1d) was designed when the recovery after an outage could wait a minute or so and be acceptable performance. With Layer 3 switching in LANs, switching began to compete with routers running protocols because they are able to offer faster alternate paths. Rapid Spanning Tree Protocol (RSTP or IEEE 802.1w) brought the ability to take the twenty seconds of waiting for the Max Age counter plus fifteen seconds of Listening plus fifteen seconds of Learning or fifty seconds down to less than one second for point-to-point connected and edge switches and six seconds for root switches.
In a recent post, I gave an overall description of a service portfolio and the key components of a portfolio. Here, I will describe how a cloud services provider might implement an ITIL service portfolio. A cloud services provider will regularly have a set of services under development, a set of service in live operation, and a set of services that are retired.
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.
In 1998, the Internet Engineering Task Force (IETF) released RFC 2460, outlining the technical specifications of IPv6, which addressed the shortcomings of the aging IPv4 protocol. As with any evolution of technology, new elements exist in the protocol that may seem strange and unfamiliar. This certainly includes address representation, space, and so forth, but also includes a number of different types of addresses as well. A subset of these new addressing types has corresponding types in IPv4, but many will seem significantly different. The purpose of this white paper is to examine addressing classifications in detail and outline their functions within the context of the protocol.
Depending on the switch vendor, the exact steps will vary on how to set up and configure VLANs on a switch. For the network design shown, the general process for setting up VLANs on the switch is:
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.
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.
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.
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).
While Apple has created many fine things, they were yet to be created themselves when Xerox PARC scientists created Media Access Control addresses. These MAC addresses are 48 bits or 6 bytes long, so they are also known as MAC-48 or EUI-48. EUI stands for Extended Unique Identifier. It is written in hexadecimal characters as shown below:
“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).
For us wireless folks that aren’t stellar routing and switching guys, one of the most daunting network tasks is integrating our WLAN infrastructure with the existing wired infrastructure and its services. Understanding wired design topics is pretty fundamental to installing or managing any network, so it really should be on our priority list to spruce up those skills. To give you a nudge on your journey, let’s talk about DHCP for wireless clients.
In this hour-long webinar, security expert and Global Knowledge instructor Phillip D. Shade will provide insight into the emerging network security science of network forensics analysis, a.k.a. security event analysis and reconstruction. Using case studies, you will examine the role of data retention in network forensics analysis, and you will learn about applying forensics analysis techniques to handle application-based attacks, VoIP call interception, and worms, bots, and viruses.
In this hour-long webinar, Global Knowledge instructor John Barnes will guide you through implementing Cisco private VLANs. He will review VLANs and 802.1q, and he will discuss private VLAN fundamentals and operation, covering primary VLANs and secondary VLANs. He will cover VLAN mapping and discuss using private VLANs between multiple switches. He will also provide a use case example.
I attended a meeting this week with a customer of mine and a potential new vendor. The new vendor was there to pitch his configuration and setup service offerings for a specific ITSM toolset. My customer has already had one bad experience with an ITSM tool configuration vendor who promised one thing and delivered much less. He ended up with a tool that’s minimally used and not configured to match his business needs. He’s looking for a vendor that can understand his business needs and priorities and quickly help him get his tool configured and working in a short time frame. Then the topic of standard changes came up. My customer asked for examples of standard changes. The vendor responded, “Server reboots are an example of standard changes.”
No matter which IT field you're working in, there are several skills that are useful for every IT professional to know. Here, seven experienced IT professionals working in the networking, programming, project management, and security fields, share what they believe a...
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...
Wi-Fi networks have been misunderstood by much of the IT community since their inception. Even the reasons for this misunderstanding are kind of hard to understand. The result has been that myths about 802.11 (better known as Wi-Fi) networks have grown almost as fast as the technology itself. In this web seminar, we'll examine 11 common Wi-Fi myths and explore ways to use correct information to make your networks scalable, secure and satisfying for your users.