module ct2053n: network devices lecture week 1. agenda module introduction your module leader your...

Module CT2053N:Network DevicesLecture Week 1

Agenda• Module Introduction

Your Module Leader Your Lecturer and tutorsModule Aims/ObjectivesModule outcomes after successful completionModule Assessments and Syllabus SummaryRecommended booklist

• Week 1 Lecture CoverageLAN Devices.OSI Reference Model and encapsulation techniques in each

layers.LAN technology

Module Leaders’ Roles• Every module has two module leaders:

• Creates the main lecture/tutorial notes

• Writes coursework and examinations

• Moderates the coursework and examinations results

• Serves as a lecturer for that module (usually in London)

• Writes localised lecture/tutorial notes

• Marks the coursework and examinations (lecturers/tutors might also be involved in marking)

• Serves as a lecturer for that module

Your Lecturer Is

Saroj LamichhaneBsc Hons. (Network Engineering)The University of Northampton

Your Tutor Is…

Mr. Saroj Lamichhane

Module aims The module aims:

To gain an understanding of the operational structure of a network and its components in relation to OSI layer.

To appreciate the concept of LAN and WAN design and various devices with respect to the OSI model.

To gain an in-depth understanding of routing, routing protocols and the need for appropriate configuration.

To gain experience in configuring routers and IP addresses for a given specification

Module outcomes after successful completion

You will be able to:• Describe the functionality of Local Area

Networks (LANs) and its devices• Explain the functional behaviour of each device

in a network and its role in the functionality of a network.

• Describe TCP/IP suite of protocols and learn how to configure IP addresses

Module outcomes after successful completion…

Student will be able to:• Explain the flow of traffic on a LAN using the

Ethernet/802.3 standards.• Describe the overall purpose of Wide Area

Networks (WANs).• Describe when, why and how to configure a

router.• Identify network software management tools and

their functions.

Module Assessments• Assessments:

50% Exam 50% Practical Assignment Test

[ individual work]

Tutorials are related to the Lectures/practical and Examinations.

Workshops are related to the Practical Assignment.

Note:- Students should obtain 40% pass on aggregate from examination and coursework.

Module Syllabus Summary• The OSI model and steps in data encapsulation,

• LAN devices and technologies, TCP/IP addressing, environment, and sub-networks.

• WANS and routers, Router components, CDP and basic Networking testing, troubleshooting, router boot sequence and set up mode, Router configuration modes and procedures.

• TCP/IP protocol suite, IP addressing and subletting, access configuration.

• Routing protocols and their importance, distance vector routing, link state routing. Interior and exterior routing protocols, RIP, IGRP, layers revisited.

Highly recommended Booklist• Cisco Systems, Inc. (2003), Cisco Networking

Academy Program CCNA 1 and 2 Companion Guide, Cisco Press ISBN 1587131102.

• Cisco Systems, Inc. (2003), Cisco Networking Academy Program CCNA 1 and 2 Lab Companion, Cisco Press ISBN 1587131110.

OSI reference model

• Seven layers open system interconnection(OSI) reference model developed by ISO.

• Proposed in 1978.• Accepted in 1984.

OSI reference model…

Why Layering??• Defines and separates networking hardware and

software into distinct layers and functions• Enables programmers to specialize in a particular

level or layer of the networking model• Provides design modularity.• Encourages interoperability• Allows for standardized interfaces to be produced

by networking vendors


Layering

7. Application layer

6. Presentation layer

5. Session layer

4.Transport layer

3.Network Layer

2.Data Link layer

1.Physical layer


Reference Models

The TCP/I The TCP/IP reference model P reference model


Encapsulation / Decapsulation:


How encapsulation is done??


How decapsulation is done??

Summary of the OSI reference Model

Network DevicesWhy Network Devices??

• Separating or connecting or expanding the networks.

• Example:- repeaters, hubs, bridges, routers, switches, gateways

Network DevicesWhy Network Devices??• Separating or connecting or expanding the

networks.• Networks cannot be made larger by simply

adding new computers and more cables• If we do so….the networks will be less efficient• Segmenting or dividing the larger LANs to form

the smaller LANs and connecting them.

Network Devices… Required Components of LAN devices:

• Repeaters and Hubs• bridges• routers• switches • gateways

Network Devices…Repeaters and Hubs:• Repeaters or hubs work at the OSI physical layer to

regenerate the network’s signal and resend them to other segments

• Primitive hub can be viewed as a multiport repeater• It regenerates data and broadcasts them to all ports

Network Devices…Limitations and features of Repeaters and

Hubs:• Have only one collision domain• Do not isolate and filter packets• Can connect different types of media• The most economic way of• expanding networks

Network Devices…Bridges:• Has one input and one output• Used to isolate network traffic and computers• Has the intelligent to examine incoming packet

source and destination addresses

Network Devices…Differences Between Bridges and

RepeatersRepeaters Bridges

OSI layer Physical layer Data link layer

Dataregeneration

Regenerate data atthe signal level

Regenerate dataat the packetlevel

Reduce networktraffic

No Yes

Network Devices…Switches:• Switches operate at the Data Link layer 2

of the OSI model• Can interpret address information• Switches resemble bridges and can• be considered as multiport bridges• having multiports, can better use• limited bandwidth and prove • more cost-effective than bridge

Network Devices…Switches…• Switches divide a network into several isolated

channels• Packets sending from 1 channel will not go to

another if not specify• Each channel has its own capacity and need not

be shared with other channels

Network Devices…Switches…

10Mbps

10Mbps

10Mbps

10Mbps

3.3 Mbps

3.3 Mbps

3.3 Mbps

Hub

Switch

Network Devices…Routers:• Layer 2 Switches cannot take advantage of

multiple paths • Routers work at the OSI layer 3 (network layer)They use the “logical address” of packets and

routing tables to determine the best path for data delivery

Network Devices…

Network devices…• Distinguish between switch/bridge and router

•Bridges forward everything they don’t recognize

•Routers select the best path • Routers are layer 3 devices which

recognize network address• Bridges are layer 2 devices which look at

the MAC sublayer node address

Summary• Repeaters are the least expensive way to expand a

network, but they are limited to connecting two segments

• Bridges function similar to repeaters, but can understand the node addresses

• Switches can be considered as multiport bridges, can divide a network into some logical channels

• Routers interconnect networks and provide filtering functions. They can determine the best route

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