cisco ccna presentation slide

5/26/2018 Cisco Ccna Presentation Slide

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2003, Cisco Systems, Inc. All rights reserved.


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Data Networks

Sharing data through the use of floppy disks is not an efficient

or cost-effective manner in which to operate businesses.

Businesses needed a solution that would successfully

address the following three problems:

How to avoid duplication of equipment and resources

How to communicate efficiently

How to set up and manage a network

Businesses realized that networking technology could

increase productivity while saving money.


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Networking Devices

Equipment that connects directly to a network segment is

referred to as a device.

These devices are broken up into two classifications.

end-user devices

network devices

End-user devices include computers, printers, scanners, and

other devices that provide services directly to the user.

Network devices include all the devices that connect the end-

user devices together to allow them to communicate.


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Network Interface Card

A network interface card (NIC) is a printed circuit board

that provides network communication capabilities to and

from a personal computer. Also called a LAN adapter.


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Networking Device Icons


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Repeater

A repeater is a network device used to regenerate a signal.

Repeaters regenerate analog or digital signals distorted by

transmission loss due to attenuation. A repeater does not

perform intelligent routing.


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Hub

Hubs concentrate

connections. In other words,

they take a group of hosts

and allow the network to see

them as a single unit.

This is done passively,

without any other effect on

the data transmission.

Active hubs not only

concentrate hosts, but they

also regenerate signals.


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Bridge

Bridges convert network transmission data formats as well as

perform basic data transmission management. Bridges, as

the name implies, provide connections between LANs. Not

only do bridges connect LANs, but they also perform a check

on the data to determine whether it should cross the bridge ornot. This makes each part of the network more efficient.


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Workgroup Switch

Workgroup switches add

more intelligence to data

transfer management.

Switches can determine

whether data should remain

on a LAN or not, and they

can transfer the data to the

connection that needs that

data.


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Router

Routers have all capabilities of the previous devices. Routerscan regenerate signals, concentrate multiple connections,

convert data transmission formats, and manage data

transfers.They can also connect to a WAN, which allows them

to connect LANs that are separated by great distances.


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The Cloud

The cloud is used in diagrams to represent where the

connection to the internet is.

It also represents all of the devices on the internet.


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Network Topologies

Network topology defines the structure of the network.

One part of the topology definition is the physical topology,

which is the actual layout of the wire or media.

The other part is the logical topology,which defines how the

media is accessed by the hosts for sending data.


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Physical Topologies


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Bus Topology

A bus topology uses a single backbone cable that is

terminated at both ends.

All the hosts connect directly to this backbone.


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Ring Topology

A ring topology connects one host to the next and the last host

to the first.

This creates a physical ring of cable.


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Star Topology

A star topology connects all cables to a central point of

concentration.


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Extended Star Topology

An extended star topology links individual stars together by

connecting the hubs and/or switches.This topology can extend

the scope and coverage of the network.


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Hierarchical Topology

A hierarchical topology is similar to an extended star.


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Mesh Topology

A mesh topology is implemented to provide as muchprotection as possible from interruption of service.

Each host has its own connections to all other hosts.

Although the Internet has multiple paths to any one

location, it does not adopt the full mesh topology.


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LANs, MANs, & WANs

One early solution was the creation of local-area network

(LAN) standards which provided an open set of guidelines for

creating network hardware and software, making equipment

from different companies compatible.

What was needed was a way for information to move

efficiently and quickly, not only within a company, but also

from one business to another.

The solution was the creation of metropolitan-area networks

(MANs) and wide-area networks (WANs).


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Examples of Data Networks


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LANs


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Wireless LAN Organizations

and Standards

In cabled networks, IEEE is the prime issuer of standards for

wireless networks. The standards have been created within the

framework of the regulations created by the Federal

Communications Commission (FCC).

A key technology contained within the 802.11 standard is Direct

Sequence Spread Spectrum (DSSS).


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Cellular Topology for Wireless


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WANs


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SANs

A SAN is a dedicated, high-

performance network used to

move data between servers

and storage resources.

Because it is a separate,

dedicated network, it avoidsany traffic conflict between

clients and servers.


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Virtual Private Network

A VPN is a private network that is constructed within a public network

infrastructure such as the global Internet. Using VPN, a telecommuter

can access the network of the company headquarters through the

Internet by building a secure tunnel between the telecommuters PC

and a VPN router in the headquarters.


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Bandwidth


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Measuring Bandwidth


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Why do we need the OSI Model?

To address the problem of networks increasing in size

and in number, the International Organization for

Standardization (ISO) researched many network

schemes and recognized that there was a need tocreate a network model that would help network

builders implement networks that could communicate

and work together and therefore, released the OSI

reference model in 1984.


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Dont Get Confused.

ISO - International Organization for Standardization

OSI - Open System Interconnection

IOS - Internetwork Operating System

The ISO created the OSI to make the IOS more

efficient. The ISO acronym is correct as shown.

To avoid confusion, some people say International

Standard Organization.


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The OSI Reference Model

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link1 Physical

The OSI Model will beused throughout your

entire networking

career!

Memorize it!


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Layer 7 - The Application Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network


This layer deal withnetworking applications.

Examples:

EmailWeb browsers

PDU - User Data


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Layer 6 - The Presentation Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network


This layer is responsiblefor presenting the data in

the required format which

may include:

EncryptionCompression

PDU - Formatted Data


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Layer 5 - The Session Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

This layer establishes,manages, and terminates

sessions between two

communicating hosts.

Example:

Client Software

( Used for logging in)

PDU - Formatted Data


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Layer 4 - The Transport Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

This layer breaks up thedata from the sending host

and then reassembles it in

the receiver.

It also is used to insure

reliable data transport

across the network.

PDU - Segments


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Layer 3 - The Network Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

Sometimes referred to as theCisco Layer.

Makes Best Path

Determination decisionsbased on logical addresses

(usually IP addresses).

PDU - Packets


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Layer 2 - The Data Link Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

This layer provides reliabletransit of data across a

physical link.

Makes decisions based onphysical addresses (usually

MAC addresses).

PDU - Frames


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Layer 1 - The Physical Layer

7 Application

6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

This is the physical media

through which the data,represented as electronic

signals, is sent from the

source host to the

destination host.

Examples:

CAT5 (what we have)Coaxial (like cable TV)

Fiber optic

PDU - Bits

OSI Model Analogy


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OSI Model Analogy

Application Layer - Source Host

After riding your new bicycle a few times in

NewYork, you decide that you want to give it to a

friend who lives in Munich,Germany.

OSI Model Analogy


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OSI Model Analogy

Presentation Layer - Source Host

Make sure you have the proper directions to

disassemble and reassemble the bicycle.

OSI Model Analogy


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OSI Model Analogy

Session Layer - Source Host

Call your friend and make sure you have his

correct address.

OSI Model Analogy


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OSI Model Analogy

Transport Layer - Source Host

Disassemble the bicycle and put different pieces

in different boxes. The boxes are labeled

1 of 3, 2 of 3, and 3 of 3.

OSI Model Analogy


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OSI Model Analogy

Network Layer - Source Host

Put your friend's complete mailing address (and

yours) on each box.Since the packages are too

big for your mailbox (and since you dont have

enough stamps) you determine that you need to

go to the post office.

OSI Model Analogy


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OSI Model Analogy

Data Link LayerSource Host

NewYork post office takes possession of the

boxes.

OSI Model Analogy


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OSI Model Analogy

Physical Layer - Media

The boxes are flown from USA to Germany.

OSI Model Analogy


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OSI Model Analogy

Data Link Layer - Destination

Munich post office receives your boxes.

OSI Model Analogy


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OSI Model Analogy

Network Layer - Destination

Upon examining the destination address,Munich post office determines that your

boxes should be delivered to your written

home address.

OSI Model Analogy


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OSI Model Analogy

Transport Layer - Destination

Your friend calls you and tells you he got all 3

boxes and he is having another friend named

BOB reassemble the bicycle.

OSI Model Analogy


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OSI Model Analogy

Session Layer - Destination

Your friend hangs up because he is done talking

to you.

OSI Model Analogy


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OSI Model Analogy

Presentation Layer - Destination

BOB is finished and presents the bicycle to

your friend. Another way to say it is that your

friend is finally getting him present.

OSI Model Analogy


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OSI Model Analogy

Application Layer - Destination

Your friend enjoys riding his new bicycle in

Munich.

Host La ers


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Host Layers

7 Application6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

These layersonly exist in the

source and

destination host

computers.

Media Layers


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Media Layers

7 Application6 Presentation

5 Session

4 Transport

3 Network

2 Data Link

1 Physical

These layers manage

the information out in

the LAN or WAN

between the source

and destination hosts.

The OSI Layers


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The OSI Layers

Communications


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Encapsulation Process

Data Flow Through a Network


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Data Flow Through a Network


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LAN Physical Layer


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LAN Physical Layer

Various symbols are used to represent media types.

The function of media is to carry a flow of information

through a LAN.Networking media are considered

Layer 1, or physical layer, components of LANs.

Each media has advantages and disadvantages.

Some of the advantage or disadvantage comparisons

concern:

Cable length

Cost

Ease of installation

Susceptibility to interference

Coaxial cable, optical fiber, and even free space can

carry network signals. However, the principal medium

that will be studied is Category 5 unshielded twisted-

pair cable (Cat 5 UTP)

Unshielded Twisted Pair (UTP) Cable


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Unshielded Twisted Pair (UTP) Cable

UTP Implementation


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UTP Implementation

EIA/TIA specifies an RJ-45 connector for UTP cable.

The RJ-45 transparent end connector shows eight colored wires.

Four of the wires carry the voltage and are considered tip (T1 through T4).

The other four wires are grounded and are called ring (R1 through R4).

The wires in the first pair in a cable or a connector are designated as T1 & R1

Connection Media


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Connection Media

The registered jack (RJ-45) connector and jack are the most

common.

In some cases the type of connector on a network interface

card (NIC) does not match the media that it needs to connectto.

The attachment unit interface (AUI) connector allows different

media to connect when used with the appropriate transceiver.

A transceiver is an adapter that converts one type of

connection to another.

Ethernet Standards


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Ethernet Standards

The Ethernet standard specifies that each of the pins on anRJ-45 connector have a particular purpose. A NIC transmits

signals on pins 1 & 2, and it receives signals on pins 3 & 6.

Remember


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Remember

A straight-thru cablehas T568B on both ends. A crossover(orcross-connect) cable has T568B on one end and T568A on the

other. A consolecable had T568B on one end and reverse T568B

on the other, which is why it is also called a rollovercable.

Straight Thru or Crossover


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Straight-Thru or Crossover

Use straight-through cables for the following cabling:

Switch to router

Switch to PC or server

Hub to PC or serverUse crossover cables for the following cabling:

Switch to switch

Switch to hub

Hub to hub Router to router

PC to PC

Router to PC

Sources of Noise on Copper Media


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pp

Noiseis any electrical energy on thetransmission cable that makes it difficult for a

receiver to interpret the data sent from the

transmitter. TIA/EIA-568-B certification of a cable

now requires testing for a variety of types of

noise.Twis ted-pair cableis designed to takeadvantage of the effects of crosstalk in order to

minimize noise. In twisted-pair cable, a pair of

wires is used to transmit one signal.The wire pair

is twisted so that each wire experiences similar

crosstalk. Because a noise signal on one wirewill appear identically on the other wire, this

noise be easily detected and filtered at

receiver.Twisting one pair of wires in a cable also

helps to reduce crosstalk of data or noise signals

from adjacent wires.

Shielded Twisted Pair (STP) Cable


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Shielded Twisted Pair (STP) Cable

Coaxial Cable


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Coaxial Cable

Fiber Optic Cable


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Fiber Optic Cable

Fiber Optic Connectors


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Fiber Optic Connectors

Connectors are attached to the fiber ends so that the fibers canbe connected to the ports on the transmitter and receiver.

The type of connector most commonly used with multimode fiber

is the Subscriber Connector (SC connector).On single-mode

fiber, the Straight Tip (ST) connector is frequently used

Fiber Optic Patch Panels


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Fiber Optic Patch Panels

Fiber patch panels similar to the patch panels used with coppercable.

Cable Specifications


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Cable Specifications

10BASE-T

The T stands for twisted pair.

10BASE5

The 5 represents the fact that a signal can travel for approximately

500 meters 10BASE5 is often referred to as Thicknet.10BASE2

The 2 represents the fact that a signal can travel for approximately

200 meters 10BASE2 is often referred to as Thinnet.

All 3 of these specifications refer to the speed of transmission at 10Mbps and a type of transmission that is baseband, or digitally

interpreted. Thinnet and Thicknet are actually a type of networks,

while 10BASE2 & 10BASE5 are the types of cabling used in these

networks.

Ethernet Media Connector Requirements


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q

LAN Physical Layer Implementation


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y y p

Ethernet in the Campus


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Ethernet in the Campus

WAN Physical Layer


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WAN Physical Layer

WAN Serial Connection Options


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WAN Serial Connection Options

Serial Implementation of DTE & DCE


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Serial Implementation of DTE & DCE

When connecting directly to a service provider, or to a

device such as a CSU/DSU that will perform signal clocking,

the router is a DTE and needs a DTE serial cable.

This is typically the case for routers.

Back-to-Back Serial Connection


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Back to Back Serial Connection

When

performing a

back-to-back

router scenarioin a test

environment,

one of the

routers will be a

DTE and theother will be a

DCE.

Repeater


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RepeaterA repeater is a network device used to regenerate a signal.

Repeaters regenerate analog or digital signals distorted bytransmission loss due to attenuation.Repeater is a Physical

Layer device

The 4 Repeater Rule


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The 4 Repeater Rule

The Four Repeater Rule for 10-Mbps Ethernet should be

used as a standard when extending LAN segments.

This rule states that no more than four repeaters

can be used between hosts on a LAN.

This rule is used to limit latency added to frame travel by

each repeater.

Hub


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Hub

Hubs concentrate

connections.In other words,

they take a group of hosts

and allow the network to seethem as a single unit.

Hub is a physical layer

device.

Network Interface Card


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Network Interface CardThe function of a NIC is to connect a host device to the network medium.

A NIC is a printed circuit board that fits into the expansion slot on the motherboard orperipheral device of a computer. The NIC is also referred to as a network adapter.

NICs are considered Data Link Layer devices because each NIC carries a

unique code called a MAC address.

MAC Address


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MAC Address

MAC address is 48 bits in length and expressed as twelve hexadecimaldigits.MAC addresses are sometimes referred to as burned-in addresses

(BIA) because they are burned into read-only memory (ROM) and are

copied into random-access memory (RAM) when the NIC initializes.

Bridge


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Bridge

Bridges are Data Link layer devices.Connected host

addresses are learned and stored on a MAC address

table.Each bridge port has a unique MAC address

Bridges


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g

Bridging Graphic


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g g p

Switch


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Switch

Switches are Data Link

layer devices.

Each Switch port has a

unique MAC address.

Connected host MAC

addresses are learned andstored on a MAC address

table.

Switching Modes


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cut-throughA switch starts to transfer the frame as soon as the destination MACaddress is received. No error checking is available.Must use synchronous switching.

store-and-forwardAt the other extreme, the switch can receive the entire frame beforesending it out the destination port. This gives the switch software anopportunity to verify the Frame Check Sum (FCS) to ensure that the framewas reliably received before sending it to the destination.Must be used with asynchronous switching.

fragment-freeA compromise between the cut-through and store-and-forward modes.Fragment-free reads the first 64 bytes, which includes the frame header,and switching begins before the entire data field and checksum are read.

Full Duplex


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Another capability emerges when only two nodes are connected. In a network thatuses twisted-pair cabling, one pair is used to carry the transmitted signal from one

node to the other node. A separate pair is used for the return or received signal. It is

possible for signals to pass through both pairs simultaneously. The capability of

communication in both directions at once is known as full duplex.

SwitchesMAC Tables


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SwitchesParallel Communication


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Microsegmentation


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A switch is simply a bridge with many ports. When only one node is connected to aswitch port, the collision domain on the shared media contains only two nodes.

The two nodes in this small segment, or collision domain, consist of the switch port

and the host connected to it. These small physical segments are called micro

segments.

Peer-to-Peer Network


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In a peer-to-peer network, networked computers act as equal partners, or peers.

As peers, each computer can take on the client function or the server function.

At one time, computer A may make a request for a file from computer B, which

responds by serving the file to computer A. Computer A functions as client, while B

functions as the server. At a later time, computers A and B can reverse roles.

In a peer-to-peer network, individual users control their own resources. Peer-to-

peer networks are relatively easy to install and operate. As networks grow, peer-to-peer relationships become increasingly difficult to coordinate.

Client/Server Network


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In a client/server arrangement, network services are located on a dedicated

computer called a server.

The server responds to the requests of clients.

The server is a central computer that is continuously available to respond to

requests from clients for file, print, application, and other services.

Most network operating systems adopt the form of a client/server relationship.


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Why Another Model?


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Although the OSI reference model is universally

recognized, the historical and technical open standardof the Internet is Transmission Control Protocol /

Internet Protocol (TCP/IP).

The TCP/IP reference model and the TCP/IP protocolstack make data communication possible between any

two computers, anywhere in the world, at nearly the

speed of light.

The U.S. Department of Defense (DoD) created the

TCP/IP reference model because it wanted a network

that could survive any conditions, even a nuclear war.

Dont Confuse the Models


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Application

Transport

Internet

Network

Access

7 Application

6 Presentation5 Session

4 Transport

3 Network

2 Data Link

1 Physical

2 Models


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Side-By-Side

Application

Transport

Internet

Network

Access

7 Application

6 Presentation

5 Session4 Transport

3 Network

2 Data Link

1 Physical

The Application Layer


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The Application Layer

The applicationlayer of the

TCP/IP model

handles high-

level protocols,issues of

representation,

encoding, and

dialog control.

Th T t L


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The transport layer provides transport services from

the source host to the destination host. It constitutes

a logical connection between these endpoints of thenetwork. Transport protocols segment and

reassemble upper-layer applications into the same

data stream between endpoints.

The transport layer data stream provides end-to-end

transport services.

The Transport Layer

The Internet Layer


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e te et aye

The purpose of the Internet layer is to

select the best path through the network for

packets to travel. The main protocol that

functions at this layer is the Internet

Protocol (IP). Best path determination and

packet switching occur at this layer.

The Network Access Layer


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y

The network access layer is also called the host-to-

network layer. It the layer that is concerned with all of theissues that an IP packet requires to actually make a

physical link to the network media. It includes LAN and

WAN details, and all the details contained in the OSI

physical and data-link layers. NOTE: ARP & RARP work

at both the Internet and Network Access Layers.

Comparing TCP/IP & OSI Models


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NOTE: TCP/IP transport layer using UDP does not always guaranteereliable delivery of packets as the transport layer in the OSI model does.

Introduction to the Transport Layer


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The primary duties of the transport layer, Layer 4 of the OSImodel, are to transport and regulate the flow of information from

the source to the destination, reliably and accurately.

End-to-end control and reliability are provided by slidingwindows, sequencing numbers, and acknowledgments.

More on The Transport Layer


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The transport layer provides transport services from thesource host to the destination host.

It establishes a logical connection between the endpoints of

the network. Transport services include the following basic services:

Segmentation of upper-layer application data

Establishment of end-to-end operations

Transport of segments from one end host to another

end host

Flow control provided by sliding windows

Reliability provided by sequence numbers and

acknowledgments

Flow Control


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As the transport layer sends data segments, it tries to ensure that data is not lost.A receiving host that is unable to process data as quickly as it arrives could be a

cause of data loss.

Flow controlavoids the problem of a transmitting host overflowing the buffers in

the receiving host.

3-Way Handshake


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TCP requires connection establishment before data transfer begins.For a connection to be established or initialized, the two hosts mustsynchronize their Initial Sequence Numbers (ISNs).

Basic Windowing


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Data packets must bedelivered to therecipient in the sameorder in which theywere transmitted tohave a reliable,connection-oriented

data transfer.The protocol fails ifany data packets arelost, damaged,duplicated, orreceived in a differentorder.

An easy solution is tohave a recipientacknowledge thereceipt of each packetbefore the nextpacket is sent.

Sliding Window


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Sliding Windowwith Different Window Sizes


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with Different Window Sizes

TCP Sequence & Acknowledgement


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TCP


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Transmission Control Protocol (TCP) is a connection-oriented Layer 4protocol that provides reliable full-duplex data transmission.

TCP is part of the TCP/IP protocol stack. In a connection-oriented

environment, a connection is established between both ends before the

transfer of information can begin.TCP is responsible for breaking messages into segments, reassembling

them at the destination station, resending anything that is not received,

and reassembling messages from the segments.TCP supplies a virtual

circuit between end-user applications.

The protocols that use TCP include:

FTP (File Transfer Protocol)

HTTP (Hypertext Transfer Protocol)

SMTP (Simple Mail Transfer Protocol)

Telnet

TCP Segment Format


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g

UDP


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User Datagram Protocol (UDP) is the connectionless transport protocolin the TCP/IP protocol stack.

UDP is a simple protocol that exchanges datagrams, without

acknowledgments or guaranteed delivery. Error processing and

retransmission must be handled by higher layer protocols.

UDP uses no windowing or acknowledgments so reliability, if needed, is

provided by application layer protocols. UDP is designed for applications

that do not need to put sequences of segments together.

The protocols that use UDP include:

TFTP (Trivial File Transfer Protocol)

SNMP (Simple Network Management Protocol)

DHCP (Dynamic Host Control Protocol)

DNS (Domain Name System)

UDP Segment Format


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UDP Segment Format

Well Known Port Numbers


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The following port numbers should be memorized:NOTE:

The curriculum forgot to mention one of the most important port numbers.

Port 80is used for HTTPor WWWprotocols. (Essentially access to the internet.)

URL


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SNMPManaged Network


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Base 2 Number System


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101102= (1 x 24= 16) + (0 x 23= 0) + (1 x 22= 4) +

(1 x 21= 2) + (0 x 20= 0) = 22

Converting Decimal to Binary


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Convert 20110to binary:

201 / 2 = 100 remainder 1

100 / 2 = 50 remainder 0

50 / 2 = 25 remainder 0

25 / 2 = 12 remainder 1

12 / 2 = 6 remainder 0




When the quotient is 0, take all the remainders in

reverse order for your answer: 20110 = 110010012


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Network and Host Addressing


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Using the IP address of thedestination network, a router can

deliver a packet to the correct

network.

When the packet arrives at a

router connected to the

destination network, the router

uses the IP address to locate the

particular computer connected tothat network.

Accordingly, every IP address hastwo parts.

Network Layer Communication Path


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A router forwards packets from the originating network to thedestination network using the IP protocol. The packets must

include an identifier for both the source and destination networks.

Internet Addresses


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IP Addressing is a hierarchical structure.An IP address combines two

identifiers into one number. This number must be a unique number,

because duplicate addresses would make routing impossible.The

first part identifies the system's network address.The second part,

called the host part, identifies which particular machine it is on the

network.

IP Address Classes


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IP addresses are divided into classes to define the large,medium, and small networks.

Class Aaddresses are assigned to larger networks.Class Baddresses are used for medium-sized networks, &Class Cfor small networks.

Identifying Address Classes


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y g

Address Class Prefixes


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To accommodate different size networks and aid in classifying these networks, IP

addresses are divided into groups called classes.This is classful addressing.

Network and Host Division


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Each complete 32-bit IP address is broken down into a network partand a host part. A bit or bit sequence at the start of each address

determines the class of the address. There are 5 IP address classes.

Class A Addresses


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The Class A address was designed to support extremely largenetworks, with more than 16 million host addresses available.

Class A IP addresses use only the first octet to indicate the

network address. The remaining three octets provide for host

addresses.

Class B Addresses


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The Class B address was designed to support the needs ofmoderate to large-sized networks.A Class B IP address uses

the first two of the four octets to indicate the network address.

The other two octets specify host addresses.

Class C Addresses


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The Class C address space is the most commonly used of theoriginal address classes.This address space was intended to

support small networks with a maximum of 254 hosts.

Class D Addresses


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The Class D address class was created to enable multicasting in anIP address. A multicast address is a unique network address that

directs packets with that destination address to predefined groups of

IP addresses. Therefore, a single station can simultaneously transmit

a single stream of data to multiple recipients.

Class E Addresses


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A Class E address has been defined. However, the InternetEngineering Task Force (IETF) reserves these addresses for its

own research. Therefore, no Class E addresses have been

released for use in the Internet.

IP Address Ranges


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The graphic below shows the IP address range of the first octetboth in decimal and binary for each IP address class.

IPv4


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As early as 1992, the Internet EngineeringTask Force (IETF) identified two specific

concerns: Exhaustion of the remaining,

unassigned IPv4 network addresses and the

increase in the size of Internet routing tables.

Over the past two decades, numerousextensions to IPv4 have been developed.

Two of the more important of these are

subnet masks and classless interdomain

routing (CIDR).

Finding the Network Address with ANDingBy ANDing the Host address of 192.168.10.2with 255.255.255.0

(its network mask) we obtain the network address of 192 168 10 0


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(its network mask) we obtain the network address of 192.168.10.0

Network Address


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Broadcast Address


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Network/Broadcast Addressesat the Binary Level


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at the Binary Level

An IP address that has binary 0s in all host bit positions isreserved for the network address, which identifies the network.

An IP address that has binary 1s in all host bit positions is

reserved for the broadcast address, which is used to send data

to all hosts on the network. Here are some examples:

Class Network Address Broadcast Address

A 100.0.0.0 100.255.255.255

B 150.75.0.0 150.75.255.255

C 200.100.50.0 200.100.50.255

Public IP Addresses


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Unique addresses are required for each device on a network.

Originally, an organization known as the Internet Network Information

Center (InterNIC) handled this procedure.

InterNIC no longer exists and has been succeeded by the Internet Assigned

Numbers Authority (IANA).

No two machines that connect to a public network can have the same IP

address because public IP addresses are global and standardized.

All machines connected to the Internet agree to conform to the system.

Public IP addresses must be obtained from an Internet service provider

(ISP) or a registry at some expense.

Private IP Addresses


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Private IP addresses are another solution to the problem of theimpending exhaustion of public IP addresses.As mentioned, public

networks require hosts to have unique IP addresses.

However, private networks that are not connected to the Internet may

use any host addresses, as long as each host within the privatenetwork is unique.

Mixing Public andPrivate IP Addresses


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Private IP Addresses

Private IP addresses can be intermixed, as shown in the graphic, withpublic IP addresses.This will conserve the number of addresses used for

internal connections. Connecting a network using private addresses to

the Internet requires translation of the private addresses to public

addresses. This translation process is referred to as Network Address

Translation (NAT).

Introduction to Subnetting


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Subnetting a network means to use the subnet mask to divide thenetwork and break a large network up into smaller, more efficient and

manageable segments, or subnets.

With subnetting, the network is not limited to the default Class A, B, or

C network masks and there is more flexibility in the network design.

Subnet addresses include the network portion, plus a subnet field and

a host field.The ability to decide how to divide the original host portion

into the new subnet and host fields provides addressing flexibility for

the network administrator.

The 32-BitBinary IP Address


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Binary IP Address

Numbers That Show Up InSubnet Masks (Memorize Them!)


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Subnet Masks (Memorize Them!)

Addressing with Subnetworks


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Obtaining an Internet Address


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Static Assignment of an IP Address


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Static assignment

works best on small

networks.

The administrator

manually assigns and

tracks IP addressesfor each computer,

printer, or server on

the intranet.

Network printers,application servers,

and routers should be

assigned static IP

addresses.

ARP

(Address Resolution Protocol)


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SIEMENSNIXDORF

SIEM ENSNIXDORF

Host A

Host BIP Address: 128.0.10.4

HW Address: 080020021545

ARP Reply

ARP Request - Broadcast to all hostsWhat is the hardware address for IP address 128.0.10.4?

SIEMENSNIXDORF

Fig. 32 How does ARP work? (TI1332EU02TI_0004 The Network Layer, 47)

(Address Resolution Protocol)


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Fig. 33 The ARP command (TI1332EU02TI_0004 The Network Layer, 47)

1 Network = 1 Broadcast Domain


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B

Broadcast: ARP request

A

B

2 Networks = 2 Broadcast Domains

Broadcast: ARP request

ARouter

host B would reply

no one would reply

Fig. 34 Proxy-ARP concept (TI1332EU02TI_0004 The Network Layer, 49)

A


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A

Router R

Broadcast Message to all:If your IP address matches B

then please tell me your

Ethernet address

B

A

B

Yes, I know the destination

network, let me give you my

Ethernet address

I take care, to forward

IP packets to B

RARP


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Reverse Address Resolution Protocol (RARP) associates a known MAC addresseswith an IP addresses.

A network device, such as a diskless workstation, might know its MAC address but not

its IP address. RARP allows the device to make a request to learn its IP address.

Devices using RARP require that a RARP server be present on the network to answer

RARP requests.

BootP


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The bootstrap protocol (BOOTP) operates in a client-server environment and only

requires a single packet exchange to obtain IP information.

However, unlike RARP, BOOTP packets can include the IP address, as well as

the address of a router, the address of a server, and vendor-specific information.

One problem with BOOTP, however, is that it was not designed to provide

dynamic address assignment. With BOOTP, a network administrator creates a

configuration file that specifies the parameters for each device.The administrator

must add hosts and maintain the BOOTP database.

Even though the addresses are dynamically assigned, there is still a one to one

relationship between the number of IP addresses and the number of hosts.

This means that for every host on the network there must be a BOOTP profile

with an IP address assignment in it. No two profiles can have the same IP

address.

DHCP


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Dynamic host configuration protocol (DHCP) is the successor to BOOTP.

Unlike BOOTP, DHCP allows a host to obtain an IP address dynamically without the

network administrator having to set up an individual profile for each device.

All that is required when using DHCP is a defined range of IP addresses on a DHCP

server.As hosts come online, they contact the DHCP server and request an address.

The DHCP server chooses an address and leases it to that host.

With DHCP, the entire network configuration of a computer can be obtained in one

message.

This includes all of the data supplied by the BOOTP message, plus a leased IP

address and a subnet mask.

The major advantage that DHCP has over BOOTP is that it allows users to be mobile.


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Introduction to RoutersA router is a special type of computer. It has the same basic components as a

standard desktop PC However routers are designed to perform some very specific


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standard desktop PC. However, routers are designed to perform some very specific

functions. Just as computers need operating systems to run software applications,

routers need the Internetwork Operating System software (IOS) to run configurationfiles. These configuration files contain the instructions and parameters that control the

flow of traffic in and out of the routers. The many parts of a router are shown below:

RAM


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Random Access Memory, also called dynamic RAM (DRAM)

RAM has the following characteristics and functions:

Stores routing tables

Holds ARP cache Holds fast-switching cache

Performs packet buffering (shared RAM)

Maintains packet-hold queues

Provides temporary memory for the configuration file of

the router while the router is powered on Loses content when router is powered down or restarted

NVRAM


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Non-Volatile RAM

NVRAM has the following characteristics and functions:

Provides storage for the startup configuration file

Retains content when router is powered down or

restarted

Flash


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Flash memory has the following characteristics and

functions:

Holds the operating system image (IOS)

Allows software to be updated without

removing and replacing chips on the processor

Retains content when router is powered down

or restarted

Can store multiple versions of IOS software

Is a type of electronically erasable, programmable

ROM (EEPROM)

ROM


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Read-Only Memory

ROM has the following characteristics and functions:

Maintains instructions for power-on self test

(POST) diagnostics

Stores bootstrap program and basic operating

system software

Requires replacing pluggable chips on themotherboard for software upgrades

InterfacesInterfaces have the following characteristics and functions:


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Interfaces have the following characteristics and functions:

Connect router to network for frame entry and exit

Can be on the motherboard or on a separate module

Types of interfaces:

Ethernet

Fast Ethernet

Serial

Token ring

ISDN BRI

Loopback

Console

Aux

Internal Components of a 2600 Router


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External Components of a 2600 Router


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External Connections


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Fixed InterfacesWhen cabling routers for serial connectivity, the routers will either have

fi d d l t Th t f t b i d ill ff t th t


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fixed or modular ports. The type of port being used will affect the syntax

used later to configure each interface. Interfaces on routers with fixedserial ports are labeled for port type and port number.

Modular Serial Port InterfacesInterfaces on routers with modular serial ports are labeled for port type, slot, and port

number.The slot is the location of the module.To configure a port on a modular card, it is

t if th i t f i th t t t l t b / t b U


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necessary to specify the interface using the syntax port type slot number/port number. Use

the label serial 0/1, when the interface is serial, the slot number where the module is

installed is slot 0, and the port that is being referenced is port 1.

Routers & DSL ConnectionsThe Cisco 827 ADSL router has one asymmetric digital

s bscriber line (ADSL) interface To connect a ro ter for DSL


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subscriber line (ADSL) interface. To connect a router for DSL

service, use a phone cable with RJ-11 connectors. DSL worksover standard telephone lines using pins 3 and 4 on a

standard RJ-11 connector.

Computer/Terminal Console Connection


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Modem Connection to Console/Aux Port


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HyperTerminal Session Properties


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Establishing aHyperTerminal Session


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Take the following stepsto connect a terminal to

the console port on the

router:

First, connect the

terminal using the RJ-45to RJ-45 rollover cable

and an RJ-45 to DB-9 or

RJ-45 to DB-25 adapter.

Then, configure the

terminal or PC terminalemulation software for

9600 baud, 8 data bits,

no parity, 1 stop bit, and

no flow control.

Cisco IOS

Cisco technology is built around the Cisco


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Cisco technology is built around the Cisco

Internetwork Operating System (IOS), which is thesoftware that controls the routing and switching

functions of internetworking devices.

A solid understanding of the IOS is essential for a

network administrator.

The Purpose of Cisco IOSAs with a computer, a router or switch cannot function without


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p ,

an operating system. Cisco calls its operating system the

Cisco Internetwork Operating System or Cisco IOS.

It is the embedded software architecture in all of the Cisco

routers and is also the operating system of the Catalyst

switches.

Without an operating system, the hardware does not have any

capabilities.

The Cisco IOS provides the following network services:

Basic routing and switching functions

Reliable and secure access to networked resources

Network scalability

Router Command Line

Interface


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te ace

Setup ModeSetup is not intended as the mode for entering complex protocol features in the

router The purpose of the setup mode is to permit the administrator to install a


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router. The purpose of the setup mode is to permit the administrator to install a

minimal configuration for a router, unable to locate a configuration from another

source.

In the setup mode, default answers appear in square brackets [ ]following the

question. Press the Enterkey to use these defaults.

During the setup process, Ctrl-Ccan be pressed at any time to terminate theprocess. When setup is terminated using Ctrl-C, all interfaces will be

administratively shutdown.

When the configuration process is completed in setup mode, the following options

will be displayed:

[0] Go to the IOS command prompt without saving this config.

[1] Return back to the setup without saving this config.

[2] Save this configuration to nvram and exit.

Enter your selection [2]:

Operation of Cisco IOS SoftwareThe Cisco IOS devices have three distinct operating environments or

modes:


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ROM monitor

Boot ROM Cisco IOS

The startup process of the router normally loads into RAM and executes

one of these operating environments. The configuration register setting can

be used by the system administrator to control the default start up mode forthe router.

To see the IOS image and version that is running, use the show version

command, which also indicates the configuration register setting.

IOS File System Overview


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Initial Startup of Cisco RoutersA router initializes by loading the bootstrap, the operating system, and a

configuration file


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configuration file.

If the router cannot find a configuration file, it enters setup mode.

Upon completion of the setup mode a backup copy of the configuration file

may be saved to nonvolatile RAM (NVRAM).

The goal of the startup routines for Cisco IOS software is to start the routeroperations. To do this, the startup routines must accomplish the following:

Make sure that the router hardware is tested and functional.

Find and load the Cisco IOS software.

Find and apply the startup configuration file or enter the setup

mode.

When a Cisco router powers up, it performs a power-on self test (POST).

During this self test, the router executes diagnostics from ROM on all

hardware modules.

After the PostAfter the POST, the following events occur as the router initializes:

Step 1


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Step 1The generic bootstrap loader in ROM executes. A bootstrap is a simple set ofinstructions that tests hardware and initializes the IOS for operation.

Step 2The IOS can be found in several places. The boot field of the configuration registerdetermines the location to be used in loading the IOS. If the boot field indicates aflash or network load, boot system commands in the configuration file indicate the

exact name and location of the image.

Step 3The operating system image is loaded.

Step 4The configuration file saved in NVRAM is loaded into main memory and executedone line at a time. The configuration commands start routing processes, supplyaddresses for interfaces, and define other operating characteristics of the router.

Step 5If no valid configuration file exists in NVRAM, the operating system searches for anavailable TFTP server. If no TFTP server is found, the setup dialog is initiated.

Step in Router Initialization


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Router LED IndicatorsCisco routers use LED indicators to provide status information.

Depending upon the Cisco router model, the LED indicators will


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p g p ,

vary. An interface LED indicates the activity of the corresponding

interface. If an LED is off when the interface is active and the

interface is correctly connected, a problem may be indicated. If an

interface is extremely busy, its LED will always be on. The green OK

LED to the right of the AUX port will be on after the system initializes

correctly.

Enhanced

Cisco IOS Commands


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The show version CommandThe show versioncommand displays information about the Cisco IOS

ft i th t i tl i th t Thi i l d th


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software version that is currently running on the router. This includes the

configuration register and the boot field settings.

The following information is available from the show versioncommand:

IOS version and descriptive information

Bootstrap ROM version

Boot ROM version Router up time

Last restart method

System image file and location

Router platform

Configuration register setting

Use the show versioncommand to identify router IOS image and boot

source. To find out the amount of flash memory, issue the show flash

command.

rmation

mand


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CheckingFileSy

stemI

nf

or

withs

how

versioncom

m


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Router User Interface ModesThe Cisco command-line interface (CLI) uses a hierarchical structure. This

structure requires entry into different modes to accomplish particular tasks


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structure requires entry into different modes to accomplish particular tasks.

Each configuration mode is indicated with a distinctive prompt and allows

only commands that are appropriate for that mode.

As a security feature the Cisco IOS software separates sessions into two

access levels, user EXEC mode and privileged EXEC mode. The privilegedEXEC mode is also known as enable mode.

Overview of Router Modes


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Router Modes


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User Mode Commands


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Privileged Mode Commands


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NOTE:

There are

many more

commandsavailable in

privileged

mode.

Specific Configuration Modes


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CLI Command ModesAll command-line interface (CLI) configuration changes to a Cisco router

are made from the global configuration mode. Other more specific modes


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g g p

are entered depending upon the configuration change that is required.

Global configuration mode commands are used in a router to apply

configuration statements that affect the system as a whole.

The following command moves the router into global configuration mode

Router#configure terminal (or config t)Router(config)#

When specific configuration modes are entered, the router prompt changes

to indicate the current configuration mode.

Typing exitfrom one of these specific configuration modes will return the

router to global configuration mode. Pressing Ctrl-Zreturns the router to all

the way back privileged EXEC mode.

Configuring a Routers NameA router should be given a unique name as one of the

fi t fi ti t k


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first configuration tasks.

This task is accomplished in global configuration

mode using the following commands:

Router(config)#hostname TokyoTokyo(config)#

As soon as the Enterkey is pressed, the promptchanges from the default host name (Router) to the

newly configured host name (which is Tokyo in the

example above).

Setting


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Setting

the Clock

with Help

Message Of The Day (MOTD)A message-of-the-day (MOTD) banner can be displayed on all

connected terminals


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connected terminals.

Enter global configuration mode by using the command config t

Enter the command

banner motd # The message of the day goes here #.

Save changes by issuing the command copy run start

Configuring a Console Password

Passwords restrict access to routers.

P d h ld l b fi d f i t l t i l


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Passwords should always be configured for virtual terminal

lines and the console line.

Passwords are also used to control access to privileged EXEC

mode so that only authorized users may make changes to the

configuration file.

The following commands are used to set an optional but

recommended password on the console line:

Router(config)#line console 0Router(config-line)#password Router(config-line)#login

Configuring a Modem Password

If configuring a router via a modem you are most likely

t d t th t


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connected to the aux port.

The method for configuring the aux port is very similar to

configuring the console port.

Router(config)#line aux 0Router(config-line)#password Router(config-line)#login

Configuring InterfacesAn interface needs an IP Address and a Subnet Mask to be configured.

All interfaces are shutdown by default.

Th DCE d f i l i t f d l k t


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The DCE end of a serial interface needs a clock rate.

Router#config tRouter(config)#interface serial 0/1Router(config-if)#ip address 200.100.50.75 255.255.255.240Router(config-if)#clock rate 56000 (required for serial DCE only)Router(config-if)#no shutdownRouter(config-if)#exitRouter(config)#int f0/0Router(config-if)#ip address 150.100.50.25 255.255.255.0Router(config-if)#no shutdownRouter(config-if)#exitRouter(config)#

exitRouter#

On older routers, Serial 0/1 would be just Serial 1 and f0/0 would be e0.

s = serial e = Ethernet f = fast Ethernet

Configuring a Telnet Password

A password must be set on one or more of the virtual terminal

(VTY) li f t i t t th t i


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(VTY) lines for users to gain remote access to the router using

Telnet.

Typically Cisco routers support five VTY lines numbered 0

through 4.

The following commands are used to set the same password

on all of the VTY lines:

Router(config)#line vty 0 4Router(config-line)#password Router(config-line)#login

Examining the show CommandsThere are many showcommands that can be used to examine the contents of files

in the router and for troubleshooting. In both privileged EXEC and user EXEC

d th d h ? id li t f il bl h d Th li t


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modes, the command show ?provides a list of available showcommands. The list

is considerably longer in privileged EXEC mode than it is in user EXEC mode.

show interfacesDisplays all the statistics for all the interfaces on the router.

show int s0/1Displays statistics for interface Serial 0/1

show controllers serialDisplays information-specific to the interface hardware

show clockShows the time set in the router

show hostsDisplays a cached list of host names and addresses

show usersDisplays all users who are connected to the router

show historyDisplays a history of commands that have been entered

show flashDisplays info about flash memory and what IOS files are stored there

show versionDisplays info about the router and the IOS that is running in RAM

show ARPDisplays the ARP table of the router

show startDisplays the saved configuration located in NVRAM

show runDisplays the configuration currently running in RAM

show protocolDisplays the global and interface specific status of any configured

Layer 3 protocols

The copy run tftp Command


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The copy tftp run Command


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Ethernet Overview

Ethernet is now the dominant LAN technology in the world


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Ethernet is now the dominant LAN technology in the world.

Ethernet is not one technology but a family of LAN

technologies.

All LANs must deal with the basic issue of how individualstations (nodes) are named, and Ethernet is no exception.

Ethernet specifications support different media, bandwidths,

and other Layer 1 and 2 variations.

However, the basic frame format and addressing scheme is

the same for all varieties of Ethernet.

Ethernet and the OSI Model

Ethernet


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operates in twoareas of the

OSI model, the

lower half of

the data linklayer, known as

the MAC

sublayer and

the physical

layer

Ethernet TechnologiesMapped to the OSI Model


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Layer 2 Framing

Framing is the Layer 2 encapsulation process


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Framing is the Layer 2 encapsulation process.

A frame is the Layer 2 protocol data unit.

The frame format diagram shows different groupings of bits

(fields) that perform other functions.

Ethernet and IEEE FrameFormats are Very Similar


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3 Common Layer 2 Technologies

Ethernet

Uses CSMA/CD logical bus topology


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Uses CSMA/CD logical bus topology

(information flow is on a linear bus)physical star or extended star (wired as

a star)

Token Ring

logical ring topology (information flow is

controlled in a ring) and a physical startopology (in other words, it is wired as a

star)

FDDI

logical ring topology (information flow is

controlled in a ring) and physical dual-ring topology(wired as a dual-ring)

Collision Domains


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To move data between one Ethernet station andanother, the data often passes through a repeater.

All other stations in the same collision domain see

traffic that passes through a repeater.

A collision domain is then a shared resource.

Problems originating in one part of the collisiondomain will usually impact the entire collision

domain.

CSMA/CD Graphic


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Backoff


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After a collision occurs and all stations allow the cable tobecome idle (each waits the full interframe spacing), then the

stations that collided must wait an additional and potentially

progressively longer period of time before attempting to

retransmit the collided frame.

The waiting period is intentionally designed to be random so

that two stations do not delay for the same amount of time

before retransmitting, which would result in more collisions.


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Hierarchical Addressing Using

Variable-Length Subnet Masks

2003, Cisco Systems, Inc. All rights reserved. 219

Prefix Length and NetworkMask

Range of Addresses: 192.168.1.64 through 192.168.1.79 Fourth Octet


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g g

Have the first 28 bits in common, which isrepresented by a /28 prefix length

28 bits in common can also be represented in dotteddecimal as 255.255.255.240

In the IP network number that accompanies the network

mask, when the host bits of the IP network number are: All binary zerosthat address is the bottom of the

address range

All binary onesthat address is the top of theaddress range

Binary ones in the network mask represent network bits in theaccompanying IP address; binary zeros represent host bits

11000000.10101000.00000001.0100xxxx IP Address

11111111.11111111.11111111.11110000 NetworkMask

64 01000000

65 01000001

66 01000010

67 01000011

68 01000100

69 0100010170 01000110

71 01000111

72 01001000

73 01001001

74 01001010

75 01001011

76 01001100

77 01001101

78 01001110

79 01001111

Implementing VLSM


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Range Of Addresses forVLSM


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Breakdown Address Spacefor Largest Subnet


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Breakdown Address Spacefor Ethernets at Remote Sites


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Address Space for SerialSubnets


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Calculating VLSM: Binary


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Summarizing Within an Octet


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Classless Interdomain Routing


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CIDR is a mechanism developed to alleviateexhaustion of addresses and reduce routingtable size.

Block addresses can be summarized into singleentries without regard to the classful boundary ofthe network number.

Summarized blocks are installed in routing

tables.

What Is CIDR?


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Addresses are the same as in the route summarization figure, except that

Class B network 172 has been replaced by Class C network 192.

CIDR Example


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Anatomy of an IP PacketIP packets consist of the data from upper layers plus an IP

header. The IP header consists of the following:


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Introducing RoutingRouting is the process that a router uses to forward packets

toward the destination network. A router makes decisions


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based upon the destination IP address of a packet. All devicesalong the way use the destination IP address to point the

packet in the correct direction so that the packet eventually

arrives at its destination. In order to make the correct

decisions, routers must learn the direction to remote networks.

Configuring Static Routes bySpecifying Outgoing Interfaces


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Configuring Static Routes bySpecifying Next-Hop Addresses


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Administrative DistanceThe administrative distance is an optional parameter that gives a measure

of the reliability of the route. The range of an AD is 0-255 where smaller


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numbers are more desireable.

The default administrative distance when using next-hop address is 1, while

the default administrative distance when using the outgoing interface is 0.

You can statically assign an AD as follows:

Router(config)#ip route 172.16.3.0

255.255.255.0 172.16.4.1 130

Sometimes static routes are used for backup purposes. A static route can

be configured on a router that will only be used when the dynamically

learned route has failed. To use a static route in this manner, simply set the

administrative distance higher than that of the dynamic routing protocol

being used.

Configuring Default RoutesDefault routes are used to route packets with destinations that do

not match any of the other routes in the routing table.


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A default route is actually a special static route that uses this format:

ip route 0.0.0.0 0.0.0.0 [next-hop-address| outgoing interface]

This is sometimes referred to as a Quad-Zero route.

Example using next hop address:

Router(config)#ip route 0.0.0.0 0.0.0.0172.16.4.1

Example using the exit interface:

Router(config)#ip route 0.0.0.0 0.0.0.0s0/0

Verifying StaticRoute Configuration


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After static routes are configured it is important to

verify that they are present in the routing table and

that routing is working as expected.

The command show running-configis used to view

the active configuration in RAM to verify that the static

route was entered correctly.

The show ip routecommand is used to make sure

that the static route is present in the routing table.

Trouble Shooting StaticRoute Configuration


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Path Determination Graphic


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Router

Routing Protocol


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Router

Router

Router Router

What is

an optimal

route ?

Switch

Switch

Routing ProtocolsRouting protocols

includes the following:

processes for sharing

f


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route informationallows routers to

communicate with

other routers to update

and maintain the

routing tables

Examples of routing

protocols that support

the IP routed protocol

are:

RIP, IGRP,OSPF, BGP,

and EIGRP.

Routing Protocols


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Routed ProtocolsProtocols used at the network layer that transfer data from one host to another acrossa router are called routed or routable protocols. The Internet Protocol (IP) and Novell's

Internetwork Packet Exchange (IPX) are examples of routed protocols. Routers use

routing protocols to exchange routing tables and share routing information. In other

words, routing protocols enable routers to route routed protocols.


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Routed Protocols


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Autonomous System

EGP

An Autonomous System (AS) is a group of IP networks, which

has a single and clearly defined external routing policy.


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AS 2000

AS 3000

IGP

Interior Gateway Protocols are

used for routing decisions

within an Autonomous System.

Exterior Gateway

Protocols are used

for routing between

Autonomous Systems

EGP

AS 1000

Fig. 48 IGP and EGP (TI1332EU02TI_0004 The Network Layer, 67)

Interior Gateway Protocol

(IGP)

Exterior Gateway

Protocol (EGP)

Interior Gateway Protocol

(IGP)


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IGPEGP

EGP

EGP

AS 1000

AS 2000

AS 3000

Fig. 49 The use of IGP and EGP protocols (TI1332EU02TI_0004 The Network Layer, 67)

IGP and EGPAn autonomous system is a network or set of networks under

common administrative control, such as the cisco.com domain.


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Categories of RoutingProtocols

Most routing algorithms can be classified into one of two


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categories:

distance vector

link-state

The distance vector routing approach determines the direction

(vector) and distance to any link in the internetwork.

The link-state approach, also called shortest path first,recreates the exact topology of the entire internetwork.

Distance VectorRouting Concepts


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Destination

192.16.1.0

192 16 5 0

Distance

1

1

Routing table contains the addresses

of destinations and the distance

of the way to this destination.

Distance Vector Routing (DVR)


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2 Hops

1 Hop1 Hop

192.16.5.0

192.16.7.0

1

2

Flow of routing

information

Router B Router CRouter A Router D

192.16.1.0 192.16.7.0

192.16.5.0

Routing Tables Graphic


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Distance VectorTopology Changes


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Router Metric Components


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192.16.3.0

192.16.2.0 192.16.6.0

Distance Vector Routing (DVR)


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Router CRouter A Router D

192.16.1.0 192.16.7.0

192.16.5.0

Router B

192.16.4.0

192.16.1.0

192.16.2.0

192.16.4.0

192.16.5.0

192.16.6.0

192.16.6.0

192.16.7.0

192.16.2.0

192.16.3.0

192.16.4.0

192.16.4.0

192.16.5.0

192.16.6.0

192.16.6.0

192.16.7.0

192.16.1.0

192.16.2.0

192.16.2.0

192.16.3.0

192.16.4.0192.16.3.0

192.16.4.0 192.16.1.0

192.16.5.0

192.16.6.0

192.16.3.0

192.16.2.0

192.16.7.0

192.16.5.0

192.16.4.0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

1

1

1

1

1

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

L

1

1

0

0

L

L

B

B A

C

C

B

B

D

C

C

L Locally connected

192.16.4.0

192.16.5.0

192.16.6.0

192.16.6.0

192.16.7.0

192.16.1.0

192.16.2.0

192.16.2.0

192.16.3.0

192.16.4.0192.16.

cisco ccna presentation slide

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