Introduction to Network Basic

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Agenda

– - Internetworking Basic – - OSI Layer– - TCP/IP Model– - IP Addressing – - Subnetting & VLSM– - The Internal Components of a Cisco Router– - The Router Boot Sequence– - IOS User Interface & CLI– - Managing Configuration Register– - Router & Switch Administrative Configuration – - Viewing, Saving, and Erasing Configurations– - Backing Up and Restoring the Cisco IOS– - Backing Up and Restoring the Cisco Configuration– - Checking Network Connectivity and Troubleshooting

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What Is a Network?

A network is a connected collection of devices that can communicate with each other. Networks carry data in many kinds of environments, including homes, small businesses, and large enterprises.

Common Physical Components of a Network

There are four major categories of physical components in a computer network: the computer, interconnections, switches, and routers.

Network History

ARPA :- Advanced Research Project Agency

Network History continued

Networking Devices

Networks are depicted graphically using a set of standard icons

- The major resources that are shared in a computer network include data and applications, peripherals, storage devices, and backup devices.

- The most common network user applications include e-mail, web browsers, instant messaging and databases.

- User applications affect the network by consuming network resources.

- The ways in which networks can be described include characteristics that address network performance and structure: speed, cost, security, availability,

scalability, reliability, and topology.

- A physical topology describes the layout for wiring the physical devices, while a logical topology describes how information flows through a network.

Bus Topology

–All devices receive the signal. In a physical bus topology, a single cable effectively connects all the devices.

Star Topology

– In a physical star topology, each device in the network is connected to the central device with its own cable.

– Transmission through a central point.– Single point of failure.

Extended-Star Topology

– When a star network is expanded to include additional networking devices that are connected to the main networking device, it is called an extended-star topology.

Ring Topology

– In a ring topology, all the hosts are connected in the form of a ring or circle.

–Single point of failure.

Dual-Ring Topology

– In a dual-ring topology, there are two rings to provide redundancy in the network.

– Signals travel in opposite directions.– More resilient than single ring.

Full-Mesh Topology

–A full-mesh topology connects all devices to each other;–Highly fault-tolerant–Expensive to implement

Partial-Mesh Topology

–Partial-mesh topology, at least one device has multiple connections to all other devices.

–Trade-off between fault tolerance and cost

Local-area Networks (LANs)

Local Area Network

LAN Components– Computers

•PCs•Servers

– Interconnections•NICs•Media

– Network devices•Hubs•Switches•Routers

– Protocols•Ethernet•IP•ARP•DHCP

Functions of a LAN

– Data and applications– Share resources– Provide communication path to other networks

LAN Standards

Wide-area Networks (WANs)

Wide-Area Network

WANs vs. LANs

WAN Access and the OSI Reference Model

WAN Devices

Routers

Terminal servers

Modems

DSU/CSU

WAN networking devices

– ATM switches

– Frame Relay switches

– PSTN

Physical Layer: WANs

Serial Point-to-Point Connections

WAN—Multiple LANs

WAN Data-Link Protocols

– HDLC– PPP– Frame Relay (LAPF) – ATM

WAN Link Options

Metropolitan-Area Network (MANs)