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2006 Cisco Systems, Inc. All rights reserved. Cisco Publ ic

Living in a Network

Centric World

Network Fundamentals

Chapter 1

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Objectives

Describe how networks impact our daily lives.

Describe the role of data networking in the humannetwork.

Identify the key components of any data network.

Identify the opportunities and challenges posed byconverged networks.

Describe the characteristics of network architectures:

fault tolerance, scalability, quality of service andsecurity.

Install and use IRC clients and a Wiki server.

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How Networks Impact Daily Life

Explain the benefits of instantaneous communicationand how it supports and improves our lives.

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Describe the characteristics and purpose of popularcommunication media such as, IM, Wikis , Blogs,Podcasting, and Collaboration Tools

Instant messaging

Real time communication

between 2 or more

people based on typed text

Weblogs (Blogs)

Web pages created

by an individualPodcasting

Website that contains

audio files available

for downloading

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Information networks can be used to share andcollaborate improves teaching and learning

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Some ways of communication over a network changethe way we work

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7/194 2006 Cisco Systems, Inc. All rights reserved. Cisco Publ ic


Communication over a network supports the way weplay

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Data Networking Role, Components, andChallenges

Basic characteristics of communicationRules or agreements are 1st established

(Before beginning to communicate with each other, we establish rules oragreements to govern the conversation. These rules, or protocols, must befollowed in order for the message to be successfully delivered and understood.)

Important information may need to be repeatedVarious modes of communication may impact theeffectiveness of getting the message across.

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The role of data networking in communications:

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Various elements make up anetwork

Devices

These are used tocommunicate with one

another

Medium

This is how the devicesare connected together

Messages

Information that travelsover the medium

Rules

Governs how messagesflow across network

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The role of converged networks in communicationsConverged network

A type of network that can carry voice, video & data overthe same network

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Network Architecture Characteristics

The four characteristics that are addressed by networkarchitecture design

Fault tolerance

Scalability

Quality of serviceSecurity

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Packet switching helps improve the resiliency and faulttolerance of the Internet architecture

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Characteristics of the Internet that help it scale to meetuser demand

Hierarchical

Common standards

Common protocols

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Explain the factors that necessitate Quality of Serviceand the mechanisms necessary to ensure it

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Describe how QoS mechanisms work to ensure qualityof service for applications that require it.

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How to select the appropriate QoS strategy for a giventype of traffic

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Why networks must be secure

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Basic measures to secure data networks

Ensure confidentiality through use of

User authentication

Data encryption

Maintain communication integrity through use ofDigital signatures

Ensure availability through use of

Firewalls

Redundant networkarchitecture

Hardware without a single

point of failure

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IRC Clients and Wiki Server

Install and use IRC clients and a Wiki server

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Summary

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Communicating over the

Network


Chapter 2

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Objectives

Describe the structure of a network, including thedevices and media that are necessary for successfulcommunications.

Explain the function of protocols in network

communications. Explain the advantages of using a layered model to

describe network functionality.

Describe the role of each layer in two recognized

network models: The TCP/IP model and the OSImodel.

Describe the importance of addressing and namingschemes in network communications.

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Network Structure Define the elements of communication

3 common elements of communication

message source

the channel

message destination

Define a network

data or information networks capable of carrying many different

types of communications

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Network Structure

Describe how messages are communicated

Data is sent across a network in small chunks calledsegments

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Network Structure

Define the components of a network

Network components

hardware

software

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Network Structure End Devices and their Role in the Network

End devices form interface with human network &communications network

Role of end devices:

client

server

both client and server

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Network Structure Identify the role of an intermediary device in a data

network and be able to contrast that role with the role ofan end device

Role of an intermediary device

provides connectivity and ensures data flowsacross network

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Network Structure

Define network media and criteria for making a networkmedia choice

Network media

this is the channel over which a message travels

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Network Types

Define Local Area Networks (LANs)

- A network serving a home, building or campus is considered aLocal Area Network (LAN)

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Network Types

Define Wide Area Networks (WANs)

- LANs separated by geographic distance are connected by anetwork known as a Wide Area Network (WAN)

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Network Types

Define the Internet

The internet is defined as a

global mesh of interconnected networks

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Network Types

Describe network representations

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Function of Protocol in NetworkCommunication

The importance of protocols and how they are used tofacilitate communication over data networks

A protocol is a set of predetermined rules

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Explain network protocols

Network protocols are used

to allow devices to

communicate

successfully

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Describe Protocol suites and industry standards

A standard is

a process or protocol that has been endorsed by thenetworking industry and ratified by a standards organization

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Define different protocols and how they interact

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Technology independent Protocols-Many diverse types of devices can communicate using thesame sets of protocols. This is because protocols specifynetwork functionality, not the underlying technology to supportthis functionality.

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Layers with TCP/IP and OSI Model Explain the benefits of using a layered model

Benefits include

assists in protocol design

fosters competition

changes in one layer do not affect other layers

provides a common language

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Layers with TCP/IP and OSI Model

Describe TCP/IP Mode

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Describe the Communication Process

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Explain protocol data units (PDU) and encapsulation

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Describe the process of sending and receivingmessages

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Explain protocol andreference models

A protocol model

provides a model thatclosely matches the

structure of a particularprotocol suite.

A reference model

provides a commonreference formaintainingconsistency within alltypes of networkprotocols and services.

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Define OSI

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Compare OSI and TCP/IP model

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Addressing and Naming Schemes

Explain how labels in encapsulation headers are usedto manage communication in data networks

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Describe examples of Ethernet MAC Addresses, IPAddresses, and TCP/UDP Port numbers

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Explain how labels in encapsulation headers are usedto manage communication in data networks

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Describe how information in the encapsulation headeris used to identify the source and destination processesfor data communication

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Summary

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Application LayerFunctionality andProtocols


Chapter 3

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Objectives

Define the application layer as the source anddestination of data for communication acrossnetworks.

Explain the role of protocols in supportingcommunication between server and clientprocesses.

Describe the features, operation, and use of

well-known TCP/IP application layer services(HTTP, DNS, SMTP).

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Applications The Interface BetweenHuman and Data Networks Explain that applications provide the means for generating and

receiving data that can be transported on the network

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Applications The Interface BetweenHuman and Data Networks Explain the role of applications, services and protocols in

converting communication to data that can be transferred acrossthe data network

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Applications The Interface BetweenHuman and Data Networks Define the separate roles applications, services and protocols play

in transporting data through networks

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Applications The Interface BetweenHuman and Data Networks Describe the role protocols play in networking and be able to

identify several message properties that can be defined by aprotocol

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The Role of Protocols in SupportingCommunication Describe the roles of client and server processes in data networks

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The Role of Protocols in SupportingCommunication List common Application Layers services and protocols

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The Role of Protocols in SupportingCommunication Compare and contrast client server networking with peer-to-peer

networking and peer-to-peer applications

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the DNS protocol and how this protocol

supports DNS services

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the HTTP protocol and how this protocol

supports the delivery of web pages to the client

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the POP and SMTP protocols, and how

these protocols support e-mail services

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the Telnet protocol and identify several of

its uses in examining and managing networks

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the SMB protocol and the role it plays in

supporting file sharing in Microsoft-based networks

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Features, Operation, and Use of TCP/IPApplication Layer Services Describe the features of the Gnutella protocol and the role it plays

in supporting P2P services

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Summary

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OSI transport layer

CCNA Exploration Semester 1

Chapter 4

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OSI transport layer

OSI model layer 4

TCP/IP model Transport layer

ApplicationPresentation

Session

Transport

Network

Data link

Physical

Application

Transport

Internet

Network Access

TCP, UDP

IP

Ethernet,

WAN

technologies

HTTP, FTP,TFTP, SMTP

etc

Segment

Packet

Frame

Bits

Data

stream

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Transport layer topics

Roles of the transport layer

TCP: Transport Control Protocol

UDP: User Datagram Protocol

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Purpose of transport layer

Responsible for the overall end-to-end transfer

of application data.

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Transport layer

Enables multiple applications on the same device tosend data over the network at the same time

Provides reliability and error handling if required.

(Checks if data has arrived and re-sends if it has not.)

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Transport Layer TCP and UDP

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Why two transport protocols?

Some applications need their data to be complete withno errors or gaps and they can accept a slight delay toensure this.They use TCP.

Some applications can accept occasional errors orgaps in the data but they cannot accept any delay.They use UDP.

Reliable

Fast

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TCP

Sets up a connection with the receiving host beforesending data.

Checks if segments have arrived and resends if theywere lost. (Reliability)

Sorts segments into the right order before reassemblingthe data.

Sends at a speed to suit the receiving host. (Flow control)

But this takes time and resources.

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UDP

Connectionless. Does not contact receiving host beforesending data.

Does not check if data arrived and does not re-send.

Does not sort into the right order.

Best effort.

Low overhead.

Used for VoIP, streaming video, DNS, TFTP

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TCP and UDP headers

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Port numbers

Used by TCP and UDP as a form of addressing.

Identifies the application and the conversation.

Common application protocols have default port

numbers e.g.80 for HTTP 110 for POP3 mail20/21 for FTP 23 for Telnet

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Port numbers

Client PC uses port 80.

Identifies HTTP as

application.

Requesting a web page.

Client PC uses port 49152.

Chosen at random.

Remembers this to identify

application and conversation.

Port + IP address = socket. E.g. 192.168.2.12:80

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Port numbers

The Internet Assigned Numbers Authority (IANA) assigns portnumbers.

Well Known Ports (0 to 1023) - Reserved for common services andapplications such as HTTP, FTP, Telnet, POP3, SMTP.

Registered Ports (1024 to 49151) - Assigned to user processes orapplications. Can be dynamically selected by a client as its sourceport.

Dynamic or Private or Ephemeral Ports (49152 to 65535) Can beassigned dynamically to client applications when initiating a

connection.

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Netstat

Shows protocol, local address and port number,

foreign address and port number.

Unexpected connections may mean there is asecurity problem.

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Segment and sequence

Both TCP and UDP split application data into suitablysized pieces for transport and re-assemble them onarrival.

TCP has sequence numbers in the segment headers. Itre-assembles segments in the right order.

UDP has no sequence numbers. It assemblesdatagrams in the order they arrive.

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Connection oriented

TCP sets up a connection between end hosts beforesending data

The two hosts go through a synchronization process toensure that both hosts are ready and know the initialsequence numbers.

This process is the Three-way handshake

When data transfer is finished, the hosts send signals to

end the session.

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Three way handshake

Send SYN

seq = x

Receive SYN

seq = x

Receive SYN

ack = y

seq = x+1

Receive ACK

ack = y+1

Send ACK

ack = y+1

Send SYN

ack = y

seq = x+1

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Terminating connection

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Expectational acknowledgement

TCP checks that data has been received.

The receiving host sends an acknowledgement givingthe sequence number of the byte that it expects next.

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Window size

Controls how many bytes are sent before an acknowledgement isexpected.

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Lost segments

Send bytes 1 to 2999

Receive 1 to 2999, send ACK 3000


Receive 3000 to 3999, send ACK 4000(bytes 4000 to 4999 were lost)


Lost segments are re-sent.

If no ACK send them all again

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Flow control

The initial window size is agreed during the three-wayhandshake.

If this is too much for the receiver and it loses data (e.g.buffer overflow) then it can decrease the window size.

If all is well then the receiver will increase the windowsize.

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Comparison of TCP and UDP

Both TCP and UDP use port numbers

Both split up application data if necessary

TCP sets up a connection

TCP uses acknowledgements and re-sends

TCP uses flow control

TCP can re-assemble segments in the right order if

they arrive out of sequence

UDP has less overhead so is faster

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Summary

Hierarchical Design model addresses performance,scalability, maintainability & manageability issues.

Traffic Analysis is used to monitor networkperformance.

Hierarchical Design Model is composed of 3 layers:Access

Distribution

Core

Switches selected for each layer must meet the needsof each hierarchical layer as well as the needs of thebusiness.

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Labs & Activities

Type Detail

PT 1.2.4 Mandatory*

Lab 1.3.1 Mandatory

PT 1.3.2 Mandatory

Lab 1.3.3 Review carefully

* If no previous Packet Tracer experience, else strongly recommended

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OSI network layer


Chapter 5

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OSI network layer

OSI model layer 3

TCP/IP model Internet layer


Session

Transport

NetworkData link

Physical

Application

Transport

Internet

Network Access

TCP, UDP

IP

Ethernet,

WAN

technologies

HTTP, FTP,TFTP, SMTP

etc

Segment

Packet

Frame

Bits

Data

stream

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Network layer topics

IP version 4 the most common layer 3 routed protocol

Dividing hosts into groups why and how

Routing sending packets the right way

Routing how routers learn routes

IP addressing in chapter 6

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Purpose of layer 3

Decide how to get the data from source to destination, then routeit.

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Layer 3 protocol

A layer 3 protocol such as IP version 4 must:

Provide an addressing scheme to identify networks andindividual hosts

Encapsulate a segment from layer 4 into a packet andinclude addresses

Direct the packet across one or many networks to thedestination host

Decapsulate (remove the packet header) and give thesegment to layer 4.

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Network layer protocols

Internet Protocol version 4 (IPv4) the most common

Internet Protocol version 6 (IPv6) designed to replaceversion 4 eventually

Novell Internetwork Packet Exchange (IPX)

AppleTalk

Connectionless Network Service (CLNS/DECNet)

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IP characteristics

Designed with low overhead for speed it does onlywhat it needs to do.

Connectionless does not set up connection withdestination before sending packet.

Best effort (unreliable) no guarantee of safe delivery, nochecking or resending.

Independent of media, but does need to know

maximum packet size.

N t k l l ti

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Network layer encapsulation

Segment from transport layer

Packet header added to make

IP packet

Sent to data link layer forfurther encapsulation into

frame

IP 4 k t h d fi ld

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IPv4 packet header fields

IP address of sourcehost, needed so reply

can be sent.

IP address of destinationhost, needed so routers

can find route.

IP 4 k t h d fi ld

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Reduced by 1 at eachrouter. Packet dropped if

it goes to 0.

TCP or UDP used inTransport layer.

IP 4 k t h d fi ld

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Priority for QoS. E.g.voice data has higher

priority than e-mail.

For checking if header hasbeen corrupted.

IP 4 k t h d fi ld

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Shows if packet hasbeen fragmented or

must not be fragmented.

If router has to split apacket, this gives order for

putting pieces together.

IP 4 k t h d fi ld

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Version 4. Length of whole packet.Headerlength.

IP h d

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IP header

S litti t k

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Splitting up networks

Fully switched network, each device has its ownbandwidth. You could have hundreds of computers.

Why split it up?

Too large to manage efficiently

Too much broadcast traffic - congestion

Too many addresses for switches to remember

Lack of security

Ho to split the net ork

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How to split the network

Geographically different sites

Purpose what software and shared resources dopeople use? How much bandwidth do they use?

Ownership different companies or departments in acompany, security requirements

Use a router

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Use a router

Limits broadcasts

Can provide security

Addressing scheme based onnetworks - hierarchical

IPv4 hierarchical address

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IPv4 hierarchical address

32 bits in four 8-bit octets, written in decimal

Network part then host part

Here network part (prefix) is 24 bits /24

Length of network part can vary.

Message to same network

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Message to same network

Message to different network

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Message to different network

Default gateway

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Default gateway

Each PC is configured with an IP address and a defaultgateway.

The default gateway is the IP address of a router porton the same network as the PC.

It is the routers job to handle messages to othernetworks.

Each router port is on a different network and has a

different IP address.

Hops

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Hops

A packet may pass through many routers on itsjourney.

The trip from one router to the next is called a hop andthe next router is called the next hop router.

Each router looks at the IP address in the packetheader and decides what to do with the packet next.

Routing table and forwarding

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Routing table and forwarding

Each router has a routing table. This contains a list ofknown networks and the best way to get there outgoingport and address of next-hop router.

The router looks at the IP address of a packet. It decides

which network this address is on.If it knows the network it forwards the packet.If it does not know the network it drops the packet.

Directly connected

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Directly connected

The networks of the routers own interfaces go into the

routing table.

Other networks

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Other networks

Routes to other networks can be configured by anadministrator (static routes)

Or they can be learned from another router using arouting protocol (dynamic routes)

A router can have a default route. Packets for unknownnetworks go on this route instead of being dropped.

Routing table entries

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Directly connected shown by C


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Static, configured by administrator,

shown by S


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Default, configured by administrator,shown by S*


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Learned from another router using RIProuting protocol, shown by R

Router has a route

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Router has a route

Routing protocols

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Routing protocols

Routers learn routes from each other and put them intheir routing tables.

A routing protocol is the set of rules they use to swapinformation.

These routes are dynamic routes

Static routes Dynamic routes

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Static routes Dynamic routes

Entered by administrator

Time consuming, different foreach router

Must be updated if routes

change

Little processing

No bandwidth used

Gives nothing away

Learned from other routers

Start the protocol then it runsby itself

Automatically updates when

routes change

More processing

Uses bandwidth

Gives away information

Summary

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Summary

Hierarchical Design model addresses performance,scalability, maintainability & manageability issues.


Hierarchical Design Model is composed of 3 layers:

Access

Distribution

Core


Labs & Activities

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Labs & Activities

Type Detail

PT 1.2.4 Mandatory*

Lab 1.3.1 Mandatory

PT 1.3.2 Mandatory



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Addressing the network IPv4

CCNA Exploration Semester 1 Chapter 6

IP addressing works at

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IP addressing works at

OSI model layer 3

TCP/IP model Internet layer


Session

Transport

NetworkData link

Physical

Application

Transport

Internet

Network Access

TCP, UDP

IP

Ethernet,

WAN

technologies

HTTP, FTP,

TFTP, SMTP

etc

Segment

Packet

Frame

Bits

Data

stream

Addressing topics

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Addressing topics

Binary and decimal

Types of IP addresses

Assigning addresses

Network part and subnet masks

Calculating addresses

Ping and Traceroute Utilities

Binary and decimal

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Binary and decimal

Convert to 8-bit binary

248

187

89

Convert to decimal

00110100

01010101

11001111

248 to binary

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248 to binary

128 64 32 16 8 4 2 1

1 1 1 1 1 0 0 0

248

-128

120

24

-16

8

56

-32

24

120

-64

56

187 to binary

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8 to b a y

128 64 32 16 8 4 2 1

1 0 1 1 1 0 1 1

187

-128

59

27

-16

11

11

-8

3

59

-32

27

3

-2

1

89 to binary

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y

128 64 32 16 8 4 2 1

0 1 0 1 1 0 0 1

89

-64

25

25

-16

9

9

-8

1

00110100 to decimal

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128 64 32 16 8 4 2 1

0 0 1 1 0 1 0 0

32 16 4

32

+16

+ 452 52

01010101 to decimal

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128 64 32 16 8 4 2 1

0 1 0 1 0 1 0 1

64 16 4 1

64

+16

+ 4+ 1

85

85

11001111 to decimal

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128 64 32 16 8 4 2 1

1 1 0 0 1 1 1 1

128 64 8 4 2 1

128

+ 64

+ 8

+ 4

+ 2

+ 1

207

207

Binary and decimal

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y

Convert to 8-bit binary

248 11111000

187 10111011

89 01011001

Convert to decimal

00110100 52

01010101 85

11001111 207

IPv4 address

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192. 168. 21. 17

11000000 10101000 00010101 00010001

octetoctet octet octet

network part host part

255. 255. 255. 0

11111111 11111111 11111111 00000000

Prefix /24 Subnet mask:

Find the network address

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192. 168. 21. 17

11000000 10101000 00010101 00010001

In a network address, all the host bits are 0.192. 168. 21. 0

11000000 10101000 00010101 00000000

The router needs to do this for every packet.

Logical AND

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g

192. 168. 21. 17

11000000 10101000 00010101 00010001

255. 255. 255. 0

11111111 11111111 11111111 00000000

Do a logical AND at each position

192. 168. 21. 0

11000000 10101000 00010101 00000000

Find the broadcast address

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192. 168. 21. 17

11000000 10101000 00010101 00010001

In a broadcast address, all the host bits are 1.192. 168. 21. 255

11000000 10101000 00010101 11111111

The broadcast is the last address in the network.

3 types of address

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Every network has:

Network address the first one

Broadcast address the last one

Host addresses everything in between

Classful addressing

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10. 17. 53. 60


A

172. 16. 38. 201


B

192. 168. 21. 17


C

Classful addressing

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Easy to work out but very wasteful.

Routers and hosts still assume class subnet masks bydefault

Class A /8 255.0.0.0 Class B /16 255.255.0.0

Class C /24 255.255.255.0

Classless addressing

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Any suitable prefix can be used

We (and devices) need to know what the prefix is.

More flexible, less wasteful.

Classless addressing /16

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172.16.0.0/16 mask 255.255.0.0

Broadcast address 172.16.255.255

Hosts 172.16.0.1 to 172.16.255.254

65534 host addresses

172. 16. 0. 0

10101100 00010000 00000000 00000000


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172.16.0.0/24 mask 255.255.255.0


Hosts 172.16.0.1 to 172.16.0.254

254 host addresses

172. 16. 0. 0

10101100 00010000 00000000 00000000


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172.16.0.0/22 mask 255.255.252.0


Hosts 172.16.0.1 to 172.16.3.254

1022 host addresses

172. 16. 0. 0

10101100 00010000 00000000 00000000


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172.16.0.0/22 mask 255.255.255.192


Hosts 172.16.0.1 to 172.16.0.62

62 host addresses

172. 16. 0. 0

10101100 00010000 00000000 00000000


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172.16.0.0/28 mask 255.255.255.240


Hosts 172.16.0.1 to 172.16.0.14

14 host addresses

172. 16. 0. 0

10101100 00010000 00000000 00000000


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A host has IP address 192.168.1.70/24

What is the subnet mask?

What is the network address?

What is the broadcast address?

What is the range of host addresses in the network?

192.168.1.70/24 fill in the table

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Last octet binary Last octetdecimal

Full

Host

Subnet mask

Network

Broadcast

First host

Last host

192.168.1.70/24

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Last octet binary Last octetdecimal

Full

Host 01000110 70 192.168.1.70

Subnet mask 00000000 0 255.255.255.0

Network 00000000 0 192.168.1.0

Broadcast 11111111 255 192.168.1.255

First host 00000001 1 192.168.1.1

Last host 11111110 254 192.168.1.254


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Last octetbinary

Last octetdecimal

Full

Host

Subnet mask

Network

Broadcast

First host

Last host

192.168.1.70/26

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Last octetbinary

Last octetdecimal

Full

Host 01000110 70 192.168.1.70

Subnet mask 11000000 192 255.255.255.192

Network 01000000 64 192.168.1.64

Broadcast 01111111 127 192.168.1.127

First host 01000001 65 192.168.1.65

Last host 01111110 126 192.168.1.126


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Last octetbinary

Last octetdecimal

Full

Host

Subnet mask

Network

Broadcast

First host

Last host

192.168.1.70/28

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Last octetbinary

Last octetdecimal

Full

Host 01000110 70 192.168.1.70

Subnet mask 11110000 240 255.255.255.240

Network 01000000 64 192.168.1.64

Broadcast 01001111 79 192.168.1.79

First host 01000001 65 192.168.1.65

Last host 01001110 78 192.168.1.78

Unicast, Multicast, Broadcast

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Unicast a message addressed to one host

Broadcast a message addressed to all hosts on anetwork. Uses networks broadcast address or255.255.255.255 locally

Multicast a message addressed to a group of hosts.Uses an address starting 224 - 239

Private IP addresses

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Unrestricted use on private networks. Not routed acrossthe Internet.

10.0.0.0 10.255.255.255 (10.0.0.0/8)

172.16.0.0 172.31.255.255 (172.16.0.0/20) 192.168.0.0 192.168.255.255 (192.168.0.0/24)

Public IP addresses

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Routed over the Internet

Master holder is IANA

Assigned to regional registries and then to ISPs

ISPs allocate them to organisations and individualusers

Use is strictly controlled as duplicate addresses are notallowed

Special addresses

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0.0.0.0 all addresses in default route. Hosts cannot begiven addresses starting 0.

127.0.0.1 is loopback. Hosts cannot be givenaddresses starting 127.

240.0.0.0 and higher reserved for experimentalpurposes.

169.254.0.0 - 169.254.255.255 local only

192.0.2.0 to 192.0.2.255 for teaching

Network address translation

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A large number of hosts on a network use privateaddresses to communicate with each other.

The ISP allocates one or a few public addresses.

NAT allows the hosts to share the public addresseswhen they want to use the Internet

Addressing hosts

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Static addressing address is configured by anadministrator

Servers, printers, routers, switches need staticaddresses

Dynamic addressing address is allocatedautomatically by DHCP by leasing addresses from apool

Dynamic addressing is best for workstations

Blocks of addresses

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Use Address range Summary

Network address 192.168.1.0 192.168.1.0/25

User hosts 192.168.1.1-127

Servers 192.168.1.128 - 191 192.168.1.128/26

Peripherals 192.168.1.192 - 223 192.168.1.192/27

Network devices 192.168.1.224 - 253 192.168.1.224/27

Router 192.168.1.254

Broadcast 192.168.1.255

Subnetting 192.168.1.0/24

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Address 192.168.1.0 00000000

Subnet mask 255.255.255.0 00000000

Last octet binary

Borrow 1 bit from host part, give it to network part, /25

Addresses 192.168.1.0192.168.1.128

0000000010000000

Subnet mask 255.255.255.128 10000000


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Borrow 2 bits from host part, give to network part, /26Addresses 192.168.1.0

192.168.1.64192.168.1.128192.168.1.192

00000000010000001000000011000000

Subnet mask 255.255.255.192 11000000


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Borrow 3 bits from host part, give to network part, /27Addresses 192.168.1.0

192.168.1.32192.168.1.64192.168.1.96

192.168.1.128192.168.1.160192.168.1.192192.168.1.224

00000000001000000100000001100000

10000000101000001100000011100000

Subnet mask 255.255.255.224 11100000


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Borrow 4 bits from host part, give to network part, /28192.168.1.0192.168.1.16192.168.1.32192.168.1.48192.168.1.64

192.168.1.80192.168.1.96192.168.1.112

192.168.1.128192.168.1.144192.168.1.160192.168.1.176192.168.1.192

192.168.1.208192.168.1.224192.168.1.240

0000000000010000001000000011000001000000

010100000110000001110000

1000000010010000101000001011000011000000

110100001110000011110000

Subnet mask 255.255.255.240 11110000

And so on


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Every time you borrow another bit you:

Double the number of subnets

Halve the size of the subnets

Each subnet has a network address, a broadcastaddress, and everything in between is a host address.

Here are some ways of visualising the process.


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Bits borrowed 1 2 3 4 5 6

No of networks 2 4 8 16 32 64

Prefix /25 /26 /27 /28 /29 /30

Bit value/ networksize

128 64 32 16 8 4

No of hosts 126 62 30 14 6 2

Subnet mask 128 192 224 240 248 252

Address space

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Make a spreadsheet or table with numbers 0 to 255

Link to show table

Subnet chart
http://localhost/var/www/apps/conversion/tmp/scratch_10/SubnettingVisual.ppthttp://localhost/var/www/apps/conversion/tmp/scratch_10/SubnettingVisual.ppt

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Subnetting

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There are many subnet calculators, but you will not beable to use them in exams.

Start with the biggest subnet and work down to thesmallest.

Make sure the subnets are valid sizes with valid subnetmasks.

Make sure that there are no overlaps.

Ping and traceroute

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Ping sends an ICMP message. If all is well, thedestination replies. If not, a router may reply to say thedestination is unreachable, or the ping may time out.

Traceroute sends a series of messages so that each

router along the path replies. You get a list ofaddresses of all the routers.

IPv6

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Development started in 1990s because of concernsabout IPv4 addresses running out

A whole new protocol suite not just layer 3

Uses 128-bit hierarchical addressing, written usinghexadecimal

Simpler header

Integrated security authentication, privacy

Quality of service mechanisms

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Subnetting - visual


Chapter 6

Prefix /24

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Three octets in networkpart, last octet in host part.

All possible numbers 0

255 in last octet belong in

the same network.

Network address yellow

Broadcast address blue

Subnet mask

255.255.255.0

Prefix /25

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First bit of fourth octettaken into network part.

For every bit taken, double

number of networks, halve

their size.



Subnet mask

255.255.255.128

Prefix /26

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2 bits of fourth octet takeninto network part.



their size.



Subnet mask

255.255.255.192

Prefix /27

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their size.Network address yellow


Subnet mask

255.255.255.224

Prefix /28

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Subnet mask

255.255.255.240

Prefix /29

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Subnet mask

255.255.255.248

Prefix /30

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Subnet mask

255.255.255.252

Variable length

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Networks do not need tobe all the same size.

/27

/26

/25

Summary

Hierarchical Design model addresses performance

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Hierarchical Design model addresses performance,

scalability, maintainability & manageability issues.


Hierarchical Design Model is composed of 3 layers:

Access

Distribution

Core


Labs & Activities

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Type DetailPT 1.2.4 Mandatory*

Lab 1.3.1 Mandatory

PT 1.3.2 Mandatory



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