Archived — Networking Technology

>> The Protocol Stacks The classic 7 layers OSI model view of networks needs some embellishment to handle the variety of networks and protocols that are proliferating today. A more realistic layered model for today’s networks would employ multiple protocol stacks residing one on top of the other. Each stack incorporates several sublayers, which may provide functions resembling traditional physical, data link, and network layers. Let’s consider the IP over Ethernet network shown in the following figure. In this case, the IP network treats the SONET network as providing it with point-to-point links between IP routers. The SONET layer itself,

>> The Advantages of Optical Networks 1. Flexible Bandwidth Delivery In addition to providing enormous capacities in the network, an optical network provides a common infrastructure over which a variety of services can be delivered. These optical networks are also increasingly becoming capable of delivering bandwidth in a flexible manner where and when needed. 2. High Capacity and Immune to EMI and RFI Optical fiber offers much higher bandwidth than copper cables and is less susceptible to various kinds of electromagnetic interferences and other undesirable effects. As a result, it is the preferred medium for transmission of data at anything

>> What Is a Virtual LAN (VLAN)? A LAN is a local area network and is defined as all devices in the same broadcast domain. Here is a typical LAN structure. In the above LAN configuration, the LAN is composed of hierarchical hubs, each workgroup can be physically separated from all the other workgroups. However, this is not always possible. Consider this example. A college staff belongs to the HR department and her compute is attached to the HR Department LAN. But she is also responsible for managing the accounts relating to research grants, general teaching and research funding. In

>> What is Line Coding? In telecommunication, a line code (also called digital baseband modulation, also called digital baseband transmission method) is a code chosen for use within a communications system for baseband transmission purposes. Line coding is often used for digital data transport. Binary 1’s and 0’s, such as in PCM signaling, may be represented in various serial–bit signaling formats called line codes.   >> Why Line Coding? There are many reasons for using line coding. Each of the line codes you will be examining offers one or more of the following advantages: Spectrum Shaping and Relocation without modulation

What is OSI 7 Layer Model? In 1978, ISO developed an architecture that would allow the devices of different manufacturers to work together to communicate with different operating systems. In 1984, the ISO architecture became an international standard known as the Open Systems Interconnection (OSI) reference model. This architecture determines how hardware, software,topologies, and protocols exist and operate on a network. The OSI model is based on seven layers, as shown in the following figure. Each layer adds functionality to the previous layer and communicates with the layers directly above and below it. This model defines seven Layers that describe