Sarwara's Blog

CISCO Systems Corporation: CISCO Systems is a large corporation that produces computer networking products and services. The Linksys brand of consumer networking products is also an owned subsidiary of CISCO Systems.

Starting or building a career in computer networking: So Many people view computer networking as one of the best and "hottest" career fields available today. Some experts claim that a serious shortage of qualified people to fill these networking jobs exists, and these claims may lure some people into the fray hoping for an easy position with a fast-growing companies. Don't be fooled! Debates over the actual extent of any "shortages" aside, networking involves mostly hard work, and competition for the high-quality positions will always be strong. Continue reading to learn more about beginning or expanding a career in networking, and pick up some valuable job-hunting tips that also apply to many other types of technical careers.

Cisco Hierarchical Model Defined by Cisco to simplify the design, implementation, and maintenance of responsive, scalable, reliable, and cost-effective networks. The 3 layers are logical and not physical – there may be many devices in a single layer, or a single device may perform the functions of 2 layers, eg: core and distribution. The Cisco Hierarchical Model

CCNA 640-802Todd Lammle(6th Edition) CCNA 640-802Todd Lammle(6th Edition) CCNA 640-802Todd Lammle(6th Edition) CCNA Guide

Introduction What is Wide Area Networking?  How Internet access works  Types of telecommunications services  How to determine Internet access needs  Steps in implementing a WAN connection What is Wide Area Networking? A WAN is a network that is created using the services of the telephone company to connect LANs separated by large geographical distances  WANs require the use of special WAN protocols and devices  These protocols are usually part of a company’s Internet access  WANs introduce a new level of complexity to internetworking – such as coordinating with outside organisations eg your telecommunications provider Characteristics are: Connections are low bandwidth, with speeds from 56kbps to 2Mbps  A single Wan connection is shared by all devises on the LAN (bottleneck) – sometimes a second link is installed for the sake of redundancy  WANs cover a large geographical area  WAN technologies include ...

IPX /SPX IPX/SPX stands for Internetwork Packet Exchange/Sequenced Packet Exchange. IPX and SPX are networking protocols used primarily on networks using the Novell NetWare operating systems.  IPX is a network layer protocol (layer 3 of the OSI Model), while SPX is a transport layer protocol (layer 4 of the OSI Model). The SPX layer sits on top of the IPX layer and provides connection-oriented services between two nodes on the network. SPX is used primarily by client/server applications.  PX/SPX is a routable protocol and can be used for small and large networks. The following protocols are part of the IPX/SPX suite: 

TCP/IP Fundamental TCP/IP Suites The TCP/IP Protocol Suite The TCP/IP protocol suite, also referred to as the Internet protocol suite, is the set of communications protocols that implements the protocol stack on which the Internet and most commercial networks run. It is named after the two most important protocols in the suite: the Transmission Control Protocol (TCP) and the Internet Protocol (IP).

IEEE INTRODUCTION Institute of Electrical And Electronics professional organization for the advancement of technology related to electricity.  Formed in 1963 by the merger of IRE( Institute of Radio Engineers ) and AIEE(American Institute of Electrical Engineering)  IEEE is one of the leading standards-making organizations in the world. IEEE performs its standards making and maintaining functions through the IEEE Standards Association(IEEE-SA).  IEEE Standards The Institute of Electrical and Electronics Engineers Standards Association (IEEE-SA) is a leading developer of global industry standards in a broad-range of industries, including:  Power and Energy  Biomedical and Healthcare  Information Technology  Telecommunications  Transportation  Nanotechnology  Information Assurance  Development of IEEE Standards The IEEE standards development process can be broken down into seven basic steps, as follows: ...

Networking Device Introduction Network Segments  NICs  Repeaters  Hubs  Bridges  Switches  Routers and Brouters  Gateways Extending Networks Extending Networks Network Segments No exact definition, usually an area of a LAN, the cable connecting two devices  “The area of the network bound by bridges or switches where collisions are propagated, or the area bound by a router to prevent the propagation of broadcasts”  The more devices which are added to the network the more traffic – solution use a device to ‘filter’ the traffic.  Such a device reduces congestion, and improves overall performance . Dividing a network in to segments allows the majority of traffic to stay remain local. Broadcast A broadcast is a signal sent by one device and read by all other devices on the network  Can be used to send a message to all users, may be used by network to find the identity of all the computers on the ne...

What is the OSI model ? Open Systems Interconnection model is fundamental to all communications between network devices.  Developed in 1974 by ISO after the American Department of Defence began using the TCP/IP suite of protocols.  Finally adopted in 1977. It is now the theoretical model for how communication takes place between network devices. What are the seven layers ? Layers OSI Model Layer 7  Layer 6  Layer 5  Layer 4  Layer 3  Layer 2  Layer 1

Peer to Peer and Client Server Models Introduction Selecting a Network Architecture  Peer-to-Peer Networks  Client-Server Networks  Hybrid Networks Selecting a Network Architecture Network Architecture – The way in which computers participate in a network.  The type of architecture chosen by an organisation may include geographical location, number of users, the requirements of specific application packages, level of technical support available, existing systems, and of course cost etc.

Transmission Media         A medium is a carrier of something. Coaxial Cable Coaxial Cable Consists of a central copper core surrounded by an insulator, a braided metal shielding, called braiding, and an outer cover, called the sheath or jacket  High bandwidth – Up to 400 MHz  Max. used data rates – 100 Mbps  High quality of data transmission  Signal loss at high frequencies Thicknet Coaxial Cable Is a rigid coaxial cable approximately 1-cm thick used for the original Ethernet networks  Also called ‘thick Ethernet’, ‘yellow Ethernet’  IEEE designates Thicknet as ‘10Base5’ Ethernet, interpreted as follows –  ‘10’ for transmission rate of 10 Mbps  ‘Base’ for baseband transmission  ‘5’ for the max. segment length of a Thicknet cable, which is 500 m Thicknet Coaxial Cable Thinnet Coaxial Cable Popular medium used in Ethernet LANs in the 1980s  IEEE designates Thinnet as ‘10Base2’...

Topology refers to the way in which the network of computers is connected. The choice of topology is dependent upon--- Type and number of equipment being used  Planned applications and rate of data transfers  Required response times  Cost Types of Network Topologies Physical Topology: Physical topology defines how devices are connected to the network through the actual cables that transmit data(physical structure of the network)  Logical Topology: Logical Topology (also referred to as Signal Topology) is a network computing term used to describe the arrangement of devices on a network and how they communicate with one another.

A *networking* can be anything from a collection of computers at one location that have been tied together using a particular connectivity medium(such as copper wires) to a global network, such as internet, that uses a number of different connectivity media, including satellite technology. The network is used to transmit data, voice, even video among many users on network.networks consist of the computers, wiring, and other devices, such as hubs, switches, and routers that make up the network infrastructure. Some devices such as network interface cards,serve as the computer's connection to the network.

1.    According to the size of the Network: LAN  MAN WAN PAN CAN                                     2.    According to type of connection used: Wired Network Wireless Network 3.    According to the functional relationship(Network Architecture): Peer to Peer Network Client Server Network  According to the Size of the Network LAN (Local Area Network) A Local Area Network is a group of computers and network communication devices within a limited geographic area, such as an office building. For example, a library will have a wired or wireless LAN for users to interconnect local devices(e.g., printers, and servers). Local area networking uses switches, bridges and/or repeaters, and hubs to interconnect LANs and increase overall size. Routers are used to connect a LAN to a WAN or MAN. They are characterized by the following: High...

Network Infrastructure refers to the architecture, in terms of equipment and connections that make up a network functional. In other way, a Network Infrastructure is the physical hardware used to transmit data electronically, such as routers, switches, gateways, bridges, and hubs. The following are the details about the hardware used in a simple Network Infrastructure: Backbone: Is the main line of wire that connects networks to one another.  Router: Is located at gateway where it directs the flow and determines the route of packets as they travel from one network to another network(s). A router can be either a hardware device or software application.  Switches: Directs the flow and determines the route of packets as they travel from one segment of a Local Area Network(LAN) to another on that same LAN.