CCNA 3 Module 5 Switching Concepts

hellhollowreadingNetworking and Communications

Oct 26, 2013 (3 years and 5 months ago)

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CCNA 3 v3.1 Module 4

Switching Concepts

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Purpose of This PowerPoint


This PowerPoint primarily consists of the Target
Indicators (TIs) of this module in CCNA version
3.1.


It was created to give instructors a PowerPoint to
take and modify as their own.


This PowerPoint is:

NOT a study guide for the module final assessment.

NOT a study guide for the CCNA certification exam.


Please report any mistakes you find in this
PowerPoint by using the Academy Connection
Help link.

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To Locate Instructional Resource Materials
on Academy Connection:


Go to the Community FTP Center to locate
materials created by the instructor community


Go to the Tools section


Go to the Alpha Preview section


Go to the Community link under Resources


See the resources available on the Class home
page for classes you are offering


Search
http://www.cisco.com



Contact your parent academy!

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Objectives

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802.3 LAN Development

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Bridges

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802.3 LAN Development: Today’s LANs

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Devices Function at Layers

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Factors that Impact Network Performance


Network traffic (congestion)
.


Multitasking desktop
operating systems

(Windows, UNIX, and Mac) allow
simultaneous network transactions
.


Faster desktop
operating systems

(Windows, UNIX, and Mac) can initiate
faster network activity
.


Increased number of client/server
applications using shared network data
.

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Typical Causes of Network Congestion

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Ethernet 802.3


Performance of a shared
-
medium Ethernet/802.3
LANs is negatively affected by factors such as
the following:

The broadcast delivery nature of Ethernet.

Carrier sense multiple access collision detect
(CSMA/CD) access method allows only one host to
transmit at a time.

Multimedia applications with higher bandwidth
demand such as video and the Internet.

The latency of additional devices added by the
extension of LANs by using repeaters.

The distance added by using Layer 1 repeaters.

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Half
-
Duplex Ethernet Design

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Network Congestion

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Network Latency

Latency, or delay, is the time a frame or a
packet takes to travel from the source
station to the final destination.

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Ethernet 10BASE
-
T Transmission Times


Bit time (or slot time)



The basic unit of time in which 1
bit can be sent. For electronic or optical devices to
recognize a binary 1 or 0, there is a minimum duration
during which the bit is "on" or "off. "


Transmission time



equals the number of bits to be sent
times the bit time for a given technology. Another way to
think about transmission time is the interval between the
start and end of a frame transmission, or between the start
of a frame transmission and a collision. Small frames take
a shorter amount of time. Large frames take a longer
amount of time.

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Benefits of Using Repeaters

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Full
-
Duplex Transmitting

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LAN Segmentation

Segmentation allows network congestion to
be significantly reduced within each
segment.

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LAN Segmentation with Bridges

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LAN Segmentation with Routers

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LAN Segmentation with Switches

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LAN Switching Basics

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LAN Switch Operation

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Ethernet Switch Latency

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Layer 2 Switching

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Layer 3 Switching

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Symmetric Switching

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Asymmetric Switching

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Memory Buffering


Port
-
based memory buffering

Packets are stored in queues that are linked to
specific incoming ports.

It is p
ossible for a single packet to block all other
packets because its destination port is busy (even
if the other packets could be delivered).


Shared
-
memory buffering

All packets use a common memory buffer.

Packets in the buffer are then linked (mapped)
dynamically to the appropriate destination port.

Helps balance between 10
-

and 100
-
Mbps ports.

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Two Switching Methods

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Store
-
and
-
forward

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Cut
-
through

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Functions of Ethernet Switches

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Frame Transmission Modes

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Network Switch Using CAM

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How Switches and Bridges Filter Frames

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Microsegmentation of the Network

A switch employs “microsegmentation” to
reduce the collision domain on a LAN. The
switch does this by creating dedicated network
segments, or point
-
to
-
point connections.

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Switches and Collision Domains

The network area where frames originate and
collide is called the collision domain. All shared
media environments are collision domains.

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Three Methods of Communication

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Switches and Broadcast Domains


Broadcasting is when one transmitter tries
to reach all the receivers in the network.
The server station sends out one
message
,

and everyone on that segment
receives the message.

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Communication
B
etween Switches and
Workstations

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Summary