Data Network

A computer network or data network is a telecommunications network which allows computers to exchange data. In computer networks, networked computing devices pass data to each other along network links (data connections). The connections between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.

Network computer devices that originate, route and terminate the data are called network nodes. Nodes can include hosts such as personal computers, phones, servers as well as networking hardware. Two such devices are said to be networked together when one device is able to exchange information with the other device, whether or not they have a direct connection to each other.

Computer networks differ in the transmission media used to carry their signals, the communications protocols to organize network traffic, the network's size, topology and organizational intent. In most cases, communications protocols are layered on (i.e. work using) other more specific or more general communications protocols, except for the physical layer that directly deals with the transmission media.

Computer networks support applications such as access to the World Wide Web, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications.

Structured Cabling

Structured cabling is building or campus telecommunications cabling infrastructure that consists of a number of standardized smaller elements (hence structured) called subsystems.

Structured cabling design and installation is governed by a set of standards that specify wiring data centers, offices, and apartment buildings for data or voice communications using various kinds of cable, most commonly category 5e (CAT-5e), category 6 (CAT-6), and fiber optic cabling and modular connectors. These standards define how to lay the cabling in various topologies in order to meet the needs of the customer, typically using a central patch panel (which is normally 19 inch rack-mounted), from where each modular connection can be used as needed. Each outlet is then patched into a network switch (normally also rack-mounted) for network use or into an IP or PBX (private branch exchange) telephone system patch panel.

Lines patched as data ports into a network switch require simple straight-through patch cables at each end to connect a computer. Voice patches to PBXs in most countries require an adapter at the remote end to translate the configuration on 8P8C modular connectors into the local standard telephone wall socket. No adapter is needed in the U.S. as the 6P2C and 6P4C plugs most commonly used with RJ11 and RJ14 telephone connections are physically and electrically compatible with the larger 8P8C socket. RJ25 and RJ61 connections are physically but not electrically compatible, and cannot be used. In the UK, an adapter must be present at the remote end as the 6-pin BT socket is physically incompatible with 8P8C.

It is common to color code patch panel cables to identify the type of connection, though structured cabling standards do not require it except in the demarcation wall field. Cabling standards demand that all eight conductors in Cat5/5e/6 cable are connected, resisting the temptation to 'double-up' or use one cable for both voice and data. IP phone systems, however, can run the telephone and the computer on the same wires.

Standard

Network cabling standards are used internationally and are published by ISO/IEC, CENELEC and the Telecommunications Industry Association (TIA).[2] Building Industry Consulting Service International is a recognised independent trainer of structured cabling installers with manufacturer independent design and installation best practice documents, it also plays a major role along with industry leaders in developing and designing the US standards:

• ANSI/TIA-568-C.0, Generic Telecommunications Cabling for Customer Premises, 2009
• ANSI/TIA-568-C.1, Commercial Building Telecommunications Cabling Standard, 2009
• ANSI/TIA-568-C.2, Balanced Twisted-Pair Telecommunication Cabling and Components Standard, published 2009
• ANSI/TIA-568-C.3, Optical Fiber Cabling Components Standard, published 2008, plus errata issued in October, 2008.
• TIA-569-B (2004; Amd 1 2009) Commercial Building Standard for Telecommunications Pathways and Spaces
• ANSI/TIA/EIA-606-A-2002, Administration Standard for Commercial Telecommunications Infrastructure.

Most European countries use although CENELEC or ISO standards which are widely accepted in most parts of the world and internationally recognized, the main CENELEC document being EN50173, which introduces contextual links to the full suite of CENELEC documents. ISO11801 heads the ISO documentation.

Configuration Reference

VLAN Configuration | Cisco Routing Protocol | Virtual vs. Physical LANs: Device Functionalities | Basic Switch Configuration (Cisco) | Limit bandwidth on a Cisco Catalyst Switchport | Cisco Catalyst 3750 IOS Command | Speed Interface Configuration |