OSI model Model with 7 layers to describe communications systems The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. Its goal is the interoperability of diverse communication systems with standard protocols. The model partitions a communication system into abstraction layers. The original version of the model defined seven layers. A layer serves the layer above it and is served by the layer below it. The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO). Communication in the OSI-Model (example with layers 3 to 5) History[edit] In the late 1970s, the International Organization for Standardization (ISO) conducted a program to develop general standards and methods of networking. Description of OSI layers[edit] Layer 1: Physical Layer[edit]
How to Upgrade Cisco IOS in a Cisco Router or a Switch | ItsyourIP.com Any software is pron to have software upgrades either to fix a bug or a Security vulnerability or even for the fact the software has reached its end of life. While Network devices and appliances are no exception, the upgrade process requires a lot of precautions and measures are taken to ensure that the upgrade process doesn't fail or cause problems post installation. Upgrading Cisco IOS is no exception. Care has to be taken to ensure that the newer version is tested on a test bed before deploying in the production network especially if we are talking core network switches and routers. The following procedure takes you through the steps to successfully upgrade Cisco IOS in a Cisco Router or a Switch. Write Unsaved configurations ciscorouter# write memory Building configuration… [OK] Check space on Flash Memory ciscorouter# show flash Backup Startup Configuration ciscorouter# copy startup-config tftp Address or name of remote host []?
My New Year's Resolution: Use Social Media Efficiently - 52 Tips Flickr Photo by RedRaspu Convio invited me to share my number one New Year's resolution as part of its "Now is the Time" campaign. The goal is to encourage nonprofits to make New Year's resolutions to that help them more efficiently and effectively move people to support their organizations. On January 1st, I wrote about my goals for 2009 using Chris Brogan's process of selecting three words or larger concepts to frame them. Why the number 52? Why Your Nonprofit Should Streamline Social Media Social media is still relatively new. But, maybe you've done some of that thinking and implemented a few focused social media experiments in 2008 and have gleaned some insights. The economic crisis has changed the external environment. One of our most valued nonprofit resources is our time, especially in these days of tighter budgets and cutbacks in funding. There are many different options to executive a social media strategy, but only so much time. Mapping Strategy to Metrics, Benchmarking, and ROI
Table Of Contents I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. If you like The TCP/IP Guide, please consider the download version. If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. Thanks for your understanding! Sincerely, Charles Kozierok Author and Publisher, The TCP/IP Guide
Software Upgrade Procedure Introduction This document explains how to upgrade a Cisco IOS? software image on Cisco Access Router platforms. The examples provided from the 2600 and 3600 Series Routers also apply to the list of router platforms mentioned. The Cisco IOS Software file names can vary, based on the Cisco IOS Software release, feature set, and platform. These routers are addressed in this document: Cisco 1000 Series Routers Cisco 1400 Series Routers Cisco 1600-R Series Routers Cisco 1700 Series Routers Cisco 2600 Series Routers Cisco 2800 Series Routers Cisco 3600 Series Routers Cisco 3700 Series Routers Cisco 3800 Series Routers Cisco 4000 Series Routers Cisco 4700 Series Routers Cisco AS5300 Series Routers Cisco MC3810 Series Routers Note: You must be a registered user and you must be logged in to the Cisco.com website in order to use the troubleshooting tools described in this document. Prerequisites Requirements There are no specific requirements for this document. Components Used
Beth's Blog: How Nonprofit Organizations Can Use Social Media to Power Social Networks for Change Welcome! - SmoothWall Welcome to Appreciative Inquiry Unlimited - Watkins & Kelly EtherApe, a graphical network monitor Svitsjeprinsipper Innholdet i denne siden og sidene som ligger under alle pekerene, skal du ha kjennskap til. Både lyd og bilde kan digitaliseres. Derfor er elektronisk kommunikasjon basert på overføring av digitale signaler. En kilde sender ut en strøm av informasjon. Mange kilder med info-strøm skal behandles samtidig og overføres til mottaker så raskt som mulig. For å kunne skape en effektiv info-strøm, må info fra hver kilde deles i enheter. Figuren nedenfor viser i prinsippet hvordan enheter fra forskjellige kilder overføres på samme linje. Multipleksing er ikke en enkel metode eller prinsipp, men en samlebetegnelse på metoder og prinsipper som gjør det mulig å overføre mange signaler (telefonsamtaler, datafiler, bilder, video, ...) samtidig på en felles overføringskanal. Det skilles mellom to fundamentalt forskjellige priunsipper for multipleksing: frekvensdelt multipleksing (FDM) og tidsdelt multipleksing (TDM). Det er mulig å kombinere tids- og frekvensdelt multipleksing .
Network Cabling Standards Guide, By Siemon Home > Standards Dear customers, partners and friends, At Siemon, we believe industry standards help you achieve the most out of your networks. For this reason, we have put together a guide to network cabling and data center standards. We are pleased to introduce: Standards Informant. Standards Informant is a new website covering a wide range of standards topics including twisted-pair cabling, fiber optic cabling, data center standards, pathways and spaces, bonding and grounding, industrial premises standards, building automation systems, energy efficiency and a whole lot more. We hope you enjoy the new Standards Informant website. Thanks, - All of Us at Siemon Standards Update Learn what's going on in with standards development with this Industry Standards Activity Overview of activites in TIA, IEEE, ISO/IEC JTC 1/SC 25/WG 3 (Customer Premises Cabling), IEC SC 48B (Connectors), and BISCI. »Download PDF Shielded Copper Cabling Resource Center »Shielded Cabling Resource Center »Full Article »More