Cisco CCNA Certification: An Illustrated Guide To Ethernet CSMA/CD by Chris Bryant
When you're studying for your CCNA exams, you're going to study the theory of technologies we basically take for granted in networking. CSMA/CD is one of those technologies. It works beautifully and you don't even have to configure it. But to be an effective network troubleshooter (and to pass... The sole physical components were the Ethernet cards in the computers and coaxial cable. ... This jam signal indicates to all other devices on the Ethernet segment that there has been a collision, and they should not send data onto the wire.

Understanding the Components of a Home Network by Jeff Heaton
Home networks are becoming more common. People want to be able to share a single broadband Internet connection to several computers in the house. There are many different devices that you can use to make up your home network. If you have never heard network terminology device names like router,... What is a Hub A hub is a device that has several Ethernet ports on the back of the device. ... If you do not have an uplink port on your hub, the hub can not be easily extended if you run out of ports.

Synchronised Digital Clock Systems by David Evans
Synchronised digital clocks allow a number of individual time clock displays to show identical accurate time. Individual stand-alone digital clocks each drift at different rates eventually all display differing times. This article discusses the methods utilised to achieve synchronised digital... Ethernet NTP Digital Clock Systems Ethernet NTP digital wall clock time displays utilise NTP over Ethernet to display a continuously accurate synchronised time. ... The devices are powered over standard CAT5 cabling using Power-over-Ethernet (IEEE 802.af), the same Ethernet standard as...

Network+ Certification Exam Tutorial: Ethernet CSMA/CD Explained by Chris Bryant
When you're studying for the Network+ exam, you've got a lot of new acronyms to learn! One of the basics is CSMA/CD, which stands for Carrier Sense Multiple Access with Collision Detection. That's quite a mouthful, but it's an important term to know for both your exam and real-world success. ... On an Ethernet segment, hosts can send data at any time. ... This jam signal tells the other hosts that there has been a collision and that they should not attempt to send data at this time. ... That's an effective technique, but the two hosts still have to send their data.

Cisco CCNA Exam Tutorial: Defining Collision Domains by Chris Bryant
CCNA exam success depends on mastering the fundamentals, and two important fundamentals are knowing exactly what the terms "collision domain" and "broadcast domain" mean. In this free Cisco tutorial, we'll take a look at the term "collision domain" and how a collision domain is defined. ... We could connect each host into a separate port on a hub (a hub is basically a multiport repeater) and we'd still have one single collision domain with four hosts in it. ... If two hosts on an Ethernet segment transmit data at exactly the same time, the data from the two hosts will collide on the shared...

Server Racks by Josh Riverside
A "rack" is designed to hold items, and it is usually on a two-post or four-post frame. So a server rack is a frame that contains server components. The new server racks are designed to hold the servers and also to cool them and other electronic equipment by allowing air to flow in a... Modern designs provide accommodations for keyboard, video, mouse switches, Ethernet hubs, etc. ... Some primary advantages of server racks are improving cabling management, providing superior physical security, and easy hardware maintenance.

Vlans by Kashif Raza
In order to implement VLANs in a network environment, you'll need a Layer 2 switch that supports them. Almost all switches sold today that are described as "managed" switches provide the ability to make ports members of different VLANs. However, switches that don't provide any configuration... One of the issues with VLAN tagging is that by adding information to an Ethernet frame, the size of the frame can move beyond the Ethernet maximum of 1518 bytes, to 1522 bytes. ... That shouldn't be an issue, since most Cisco Catalyst switches provide at least one or two Fast Ethernet ports, even on...

Networking Basics by Kashif Raza
A network is a group of computers, printers, and other devices that are connected together with cables. The sharing of data and resources. Information travels over the cables, allowing network users to exchange documents & data with each other, print to the same printers, and generally share any... 10BASE-T Ethernet and Fast Ethernet use a star topology, in which access is controlled by a central computer. ... This standard defines rules for configuring an Ethernet network as well as specifying how elements in an Ethernet network interact with one another.

Penetration Testing on a Switched LAN by Brian Wilson
In this is article we will explore the presence of known vulnerabilities in switched LAN’s. I hope to open your eyes on some of the techniques & tools that can be freely downloaded and used to test your network. Let’s start out with some of the basics we see in most small to medium networks. ... Ethernet (CAT3, CAT5, or CAT6): To tap Ethernet it’s normally done by using a protocol sniffer like Ethereal. ... To sniff on an Ethernet LAN you need to have access to the network via switch port of other network connection.

Cisco Certification: The Definitive Guide To ARP, IARP, RARP, and Proxy ARP by Chris Bryant
When I first started studying for my CCNA years ago, one of the (many) things that confused me was ARP. Or rather, what ARP did as opposed to Reverse ARP, Inverse ARP, and Proxy ARP! One book would mention ARP without mentioning the other variations, one would mention RARP but not Proxy ARP, and... A repeater's job is simply to regenerate a signal to make it stronger, and a hub is simply a multiport repeater. ... Since Ethernet is a broadcast media, every other device on the segment will see it.