1. Day-1-LAN Topology and Device Symbols

8/6/2019 1. Day-1-LAN Topology and Device Symbols

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Network - Topologies

& Devices


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Network A collection of connected nodes, who

can share their resources.

Network consists of many components,

including both hardware and software.

It has two category:

LAN

WAN


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LAN and WAN LANs are used to interconnect devices

that are in relatively close proximity.

Whereas, WAN are necessary to

interconnect LANs across geographic

distances.


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Bandwidth

In analog communications, the differencebetween the highest and lowest frequencies

in a given range. In other words, it is widthof the channel. For example, an analogtelephone line accommodates a bandwidthof 3,000 hertz (Hz), the difference betweenthe lowest (300 Hz) and highest (3,300 Hz)frequencies it can carry. In digitalcommunications, bandwidth is expressed inbits per second (bps).


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Circuit Switching

It is based on the idea that

conversation across a network should

have reserved bandwidth and must

follow the same path until the

connection is broken.

Requires a dedicated channel betweencommunicating nodes.


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Packet Switching

It routes each packet through a

network individually, rather than

through a preset path of switches.

Does not require any dedicated

channel between nodes.

Each packet are having its own startand stop bit enclosed.


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Physical & Logical Topologies

Physical Topologies define the actual

layout of the wire (media).

Logical Topologies define how the

media is accessed by the hosts.


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Physical Topologies

Bus

Ring

Star

ExtendedStar

Hierarchical

Mesh


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Bus Topology

Single backbone

All hosts directly

connected to backbone Each end of the bus

must be properly

terminated


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Ring Topology No backbone

A host is directly

connected to each of itsneighbors

Used for token passing

logical topologies


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Star Topology All devices connected to

a central point

Center of star is usuallya hub or a switch

Used for Ethernet

technologies


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Extended Star Topology Connects individual star

topologies together.

At the center of the star

is a hub or a switch.

Extends the length and

size of the network.

This is the topology we

are using in our lab!


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Hierarchical Topology Like the extended star except a computer

controls trafficnot a hub or a switch.

Server


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Mesh Topology

Each host has its own

connection to every

other host

Used in situations where

communication must

not be interrupted.


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Logical Topologies Broadcast Topology

Each host on the LAN sends its data (or

broadcasts its data) to every other

host.

Token Passing Topology

Access to media is controlled by anelectronic token, possession of the

token gives the host the right to pass

data to its destination.


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LANM

edia Symbols

TokenRing

FDDI

Ring

EthernetLine

Serial

Line


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LAYER 1Repeater

Cleans up (regenerates) and repeats

the signal.

Used when a networks cabling extendsbeyond its capability.


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LAYER 1Transceiver

Transmitter and Receiver of electronic

signalsspecialized repeater.

Connects different media technologies

Also called a MAU (Media Attachment

Unit)

FiberCat 5 UTP


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LAYER 1Hub

Simply a multi-port repeater. Used to connect multiple devices to the

same network drop.

The Cloud


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Hubs1) Hubs share bandwidth between all

attached devices creating a

collision domain.

2) Hubs are non-intelligent, theycannot filter traffic.

3) Most LANs use a broadcast

topology, so every device seesevery packet sent down the

media.


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BroadcastsAll hubs forward all traffic to alldevices because they are in the

same collision domain,this iswhat is meant by a broadcasttopology

21


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Separating the collision domain

into smaller domains is called

segmentation. Bridges and switches are Layer 2

devices that segment collision

domains. These devices filter network

traffic based on MAC addresses.

Broadcasts


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LAN Device SymbolsLayer 2

Bridge

Switch


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LAYER 2Bridge

Connects two LAN segments.

Keeps traffic local by filtering trafficbased on MAC Addresses.


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BridgeTo lessen the amount of LAN traffic,bridges filter frames based on MACaddresses. The bridge recognizes theMAC address of Host 2 as being on thesame domain as Host 1

2

1


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LAYER 2Switch

Connects multiple LAN segments.

Can be called a multi-port bridge.

Provides full bandwidth out each port.

The Cloud


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SwitchA switch (also know as a multi-portbridge), can effectively replace multiple

bridges and provide each LAN

segmentwith dedicated bandwidth.

The Cloud

10 Mbps10 Mbps

10 Mbps

10 Mbps

10 Mbps


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Since a switch is a multi-port bridge,we know it will stop local pings fromtraveling to other network segments.

Switch

1

2

1

If a switch or a bridge do not recognize thedestination MAC address destined for adifferent LAN segment it will be broadcast theaddress to all segments.


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LAN Device SymbolsLayer 3

Router


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Router

Can be used to connect different Layer

2 devices and different topologies.

Makes decisions based on network

addresses (IP Addresses).

The Cloud


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Routers TwoM

ain Functions

Path Determination (routing)

Packet Switching


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Routers TwoM

ain Functions

Path Determination is the process of

evaluating a packets destination IP

address so that the router can

decide which port to send out the

packet.


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Routers TwoM

ain Functions

In PacketSwitching, the router

encapsulates the packet in the

protocol needed for the specified port

and then switches the packet out

that port.


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Router

1

16

1

Routers filter traffic based on IP addresses.The router uses the IP address to route the

traffic to the correct LAN segment.


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The Cloud

The cloud is a collection of devices that

operate at all layers (7-1) of the OSI model.

The cloud is used to represent a large

group of details that are not pertinent to a

situation or description, at a given time.

The cloud helps remind us that ourdiscussions are about various parts of a

larger interconnected networkThe

Internet.

The Cloud

Documents

1. Day-1-LAN Topology and Device Symbols