Archive for the 'Network' Category


Computer Networking Fundamentals

Computer network is an integral part of our daily lives, with the most important reason being that of communication. The use of computer networking is to share resources like fax machines, printers, modems, files etc., and its other uses are database server, computer server, email, chat, internet etc. The computer to which the resources are attached is called the server and the other computers that access the resource are called clients. In peer-to-peer computer networks there are no servers.

The sharing of fax machines, printers, and modems amongst many computers and users reduce the operational cost. A database on a computer network is a very important application as it stores and runs many important data and jobs. Emails and chats can be used for instantaneous communication and sending of files on a computer network.

The computer networks are classified, depending upon the size, as Local Area Networks (LAN), Wide Area Networks (WAN), Metropolitan Area Networks (MAN) and Personal Area Networks (PAN). The topology (topology is the way the computer networks and network resources are connected) of the networking can be classified as Bus Network, Ring Network and Star Network.

The networking hardware basically consists of wiring, network cards and a hub. Computer network cards are required so that one computer can understand what the other computer is “talking”. Network cards have a unique MAC address to identify computers on a computer network. Hubs connect all the computers in the network. Hubs can also be used to connect to other hubs to increase the size of the computer network. Two computers can be connected using Ethernet cards or phone lines or power lines for communication, with hardware kits available at roughly a cost of $100.

As the number of computers in an office or a home increases, so do the number of cables, so wireless networking is a viable solution. In wireless networking radio transreceivers or infrared signals are used to communicate between computers and devices. Examples of wireless networking include Wi-fi and Bluetooth technology, though there may be security issues involved in wireless networking. However there definitely is a stronger preference towards wireless networking nowadays among consumers.

Computer networks have added a new dimension to the 21st century. Today the cyber world is much faster and wider than the real world. This has all been made possible due to computer networks. Computer networks have revolutionized business, communication, travel, research, defense, society and almost all human endeavors. The evolution of computer networks has helped the technological revolution take a big leap forward.

For a more comprehensive look at Computer Networking, visit Susan’s site athttp://www.best-networking-solutions.info. Susan also enjoys writing on a wide range of topics athttp://www.business-and-finance-hub.info.

Posted on 25th July 2007
Under: Network | No Comments »

Sell Your Used Cisco gear: Helpful tips

Helpful tipsCisco Systems has become a name synonymous with high-quality networking hardware. It’s no wonder that many companies build their network around this brand. In addition to their robust feature-set and useful product life, Cisco products also have great investment protection and can be resold to help recoup a portion of their cost.

There are many reasons companies get rid of hardware. Sometimes companies replace dead equipment that is no longer functioning properly. In this instance, equipment can be salvaged or recycled, which amounts to getting small amounts of money for the value of the raw materials. However, more often companies are either upgrading or downsizing, in which case the equipment they are selling on the secondary market is still functioning perfectly but is no longer an integral part of a network.

There are a number of ways to go about selling your equipment on the secondary market.

EBAY

eBay is the world’s garage sale. Not only that, eBay is a great place to buy and sell used networking hardware. If you perform a search for terms like “cisco router” you will find a slew of models, both new and used to choose from. Often listed at low starting bids or “buy it now” prices, products can be acquired for a fraction of the cost of new. While these prices can sometimes be lower than what would be paid when sourcing from a reputable vendor, there are some risks that go hand in hand with buying and selling any network hardware on eBay.

For one, many eBay users post items that they may or may not currently have in stock. If an order comes in, they search the inventory of other brokers to find it at a lower cost than it was sold. This means that if they can’t source it immediately, you may be forced to wait for more time than you expected, while they source one. If you are selling used equipment, you will have to deal with buyers who may be suspicious about your listing. You should use clear language in your description, assuring the prospective buyer that the item you listed is physically in stock.

Secondly, there may be significant costs associated with freight and shipping. A fully loaded Catalyst 6500 model weighs a lot. You may end up paying a large amount of money to ship it to the buyer. This can sometimes be an unexpected cost the buyer may not be comfortable with. If you are shipping a piece of networking gear, make sure to always require insurance. This prevents any liability for items that are damaged in shipping. Since the shipper is the one who has to file a claim, this can be a real headache. Conversely, you can avoid the whole issue of shipping by stipulating that your auction will be “local pick-up only.” This means that you will not be required to complete the sale of your item if the winning bidder is not able to pick-up.

Lastly, you may be competing against vendors/members who offer a product guarantee. Most reputable vendors offer some sort of warranty for end-users, ranging from 90-days to 1-year. By not including a guarantee on your item, you may lose potential bidders who feel more comfortable having some kind of warranty on a large investment.

You can sometimes offload equipment quickly and easily on eBay; however, because of this fact, a number of established vendors utilize this service as well. In this instance, you are competing against a technology specialist who has the experience, inventory, and leverage to appeal to a large segment of buyers. In the end, your greatest weapon is price.

SECONDARY MARKET

The secondary market is a great, safe way to purchase used Cisco hardware. There are many vendors spread out across the country offering discounted gear and product guarantees. Because most companies actually house inventory, buyers stand a good chance of getting a required order filled quickly and packaged professionally. However, distance is still a factor when placing an order, as shipping charges can add substantial cost to an out of state transaction.

Finding the right company for you can be accomplished by performing specific searches in any of the major search engines. Instead of simply searching for “buy used cisco” or some other relatively general term, you can modify your search by adding a qualifying geo-specific keyword such as “San Francisco” or “sf.” The search phrase “San Francisco used cisco” will return a number of companies that are located in your geographic region, and thus will minimize shipping costs and transit time. Also, by using Yahoo’s local search filter, you can perform a general search like “buy used cisco” and then filter results to show only those companies that are physically located close by. All you need is to be logged into a Yahoo account to take advantage of this feature.

Specialized technology vendors may also offer full-service liquidation services to manage all aspects of the buying process, which minimizes the effort required on the part of the seller. Liquidation services make the most sense for companies with large amounts of hardware that they need to unload. Instead of finding buyers for individual pieces and sourcing a salvage company to recycle the unusable equipment, you can work with one point of contact who will manage all the logistics, transportation, and valuation of an entire lot of gear. This allows you to focus your energy on your core, revenue-producing activities.

The timeline from your initial communication and RFQ to an offer and full payment can depend on both the company and the size and type of the lot. Some companies offer a quote and deposit payment in as little as 48-hours of a RFQ, with the remaining balance paid upon receipt and inspection of all equipment. Your final offer will take into account the model/make, condition, and the current market demand for the used hardware. The entire process can take anywhere from 5 working days to 2 weeks. Make sure to find a company that you feel comfortable working with, as there a quite a few small brokers that do not have the capital or bandwidth to efficiently handle your business.

With adequate research and due diligence, you can find the appropriate marketplace to sell your used Cisco hardware and receive fair value for your surplus equipment.

Chris Hill has a collective 5 years experience in IT sales. He is currently Director of Carrier Sales for Townsend Assets Group (TAG), a leading reseller of pre-owned data networking and telecom equipment. For more comprehensive information on the process of selling used hardware, refer to TAG’s Sell Used Cisco page.

Posted on 2nd April 2007
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Transmit Trillion Bits Using Fibre Optic Cables

Transmit Trillion Bits Using Fibre Optic CablesThe fibre optic cables are made of thin glass strands and have the capacity of transmitting trillions of bits per second. Fibre Optic Cables use light pulses to transmit information down fibre lines instead of using electronic pulses to transmit information in copper lines. Light pulses move easily down the fibre optic line because of a principle known as total internal reflection. When this principle is applied to the construction of the fibre optic strand, it is possible to transmit information down fibre lines in the form of light pulses.

There are three basic elements of a fibre optic cable. The core, the cladding and the coating.

Core is the light transmission area of the fibre cable, either glass or plastic. The larger the core, the more light will be transmitted into the fibre.

The function of the cladding is to provide a lower refractive index at the core interface in order to cause reflection within the core so that light waves are transmitted through the fibre.

Coatings are usually multi-layers of plastic applied to preserve fibre strength, absorb shock and provide extra fibre protection. These buffer coatings are available from 250 microns to 900 microns.

The size of the optical fibre cable is commonly referred to by the outer diameter of its core, cladding and coating. Example: 50/125/250 indicates a fiber with a core of 50 microns, cladding of 125 microns, and a coating of 250 microns.

There are two basic types of fibre: multimode and single-mode. Multimode fibre cores may be either step index or graded index. The single mode has a higher capacity and capability than either of the two multimode types. For example, undersea telecommunications cables can convey 60,000 voice channels on a pair of single mode fibres.

Considerations of tensile strength, ruggedness, durability, flexibility, size and resistance to the environment, flammability, temperature range and appearance are important in optical fibre cables.

Fibre optic cable is the medium on which the broadband technology is based. Fibre optic cables have the ability to transmit multiple pieces of data simultaneously and to carry signals from different network carriers. It is simply amazing to see the many uses of Fibre optic cables.

For more information on buying different types of Fibre optic cables from leading manufacturers, log onto www.mayflex.com

Posted on 29th March 2007
Under: Network | No Comments »