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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).
Lessons learned is a theory, or conclusion, based on evidence at a given time and describes what went wrong (as well as what went right) throughout the lifecycle of a project. Although it’s completed during the project closeout process, it should occur during the entire project lifecycle to ensure all information is captured and documented. Consequences of not having a project review of lessons learned are the increased likelihood of repeating actions that might have caused:
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.
Everyone has been involved in a learning program or project that has not delivered its intended impact. Across organizations, remarkably similar but preventable missteps are made in needs identification, learning strategies, program development and implementation. Instructor Tom Gram, Senior Director of Professional Services at Global Knowledge, will present six classic mistakes learning professionals make that reduce chances for success along with evidence-based practices to help prevent them.
During a recent ITIL foundation class, a student asked an interesting question. She wanted to know: “What is the difference between a project and a service?” To be honest, I haven’t spent much time thinking about this distinction. However, I think that those of us who practice ITIL consulting and training should have good answers to questions such as this. Here’s how I answered this question.
The term "life cycle" implies two things: that a process is perpetual and that the sequence of events is obligatory or uni-directional. There is no beginning or end to a life cycle and the sequence of events cannot change. A seed cannot go directly to being a mature plant nor revert back to the blossom stage.
In my last post I discussed aspects of problem management in the context of a real-life situation regarding the first vehicle I owned. In that scenario, and throughout this series of posts, I’ve demonstrated a real-life situation from a standpoint of the incident and problem management processes that ITIL describes.
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.