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switch form factor (physical size) is important depending upon where the switch will be installed.
Wiring closet with limited space.
Computer room with free standing racks.
Shelf in a central area.
Fixed Configuration Switches:
Fixed in their configuration.
You cannot add features or options to the switch beyond those that originally came wi th the switch.
Modular Switches:
Offer more flexibility.
Typically come with different sized chassis that allow for the installation of different numbe rs of modular line
cards.
The line cards actually contain the ports.

Stackable Switches:
Interconnected using a special backplane cable that provides high-bandwidth throughput between th e switches
(Cisco StackWise).
The stacked switches effectively operate as a single, larger switch.
Desirable when fault tolerance and bandwidth availability are crit ical and a modular switch is too costly to
implement.
Switch Performance
When selecting a switch for the access, distributio n, or core layer, consider the ability of the switch to support:
Port Density.
Forwarding Rate.
Bandwidth Aggregation Requirements.
Port Density:
Port density is the number of ports available on a single switch.
Forwarding Rate:
Defines the processing capabilities of a switch by rating how much data the switch can process per sec ond.
If the switch forwarding rate is too low, it cannot accommodate full wire-speed communication across all of its
switch ports.
A 48 port Gigabit switch is capable of switching 48 Gigabits of traffic.
Access layer switches typically do not need to oper ate at full wire speed because they are physically limited by their
uplinks to the distribution layer.
Allows the use of:
Less expensive, lower performing switches at the access layer.
More expensive, higher performing switches at the distribution and core layers, where the forwarding rate makes
a bigger difference.
Link Aggregation:
As part of bandwidth aggregation, you should determ ine if there are enough ports on a switch to aggregate to
support the required bandwidth.
Power over Ethernet (PoE):
Allows the switch to deliver power to a device over the existing Ethernet cabling.
Layer 3 Functionality:
Switches typically operate at Layer 2 of the OSI Mo del.

Switch Features – Hierarchical Network
Access Layer Switch Features:
-Port security
-VLANs
-Link Aggregation
-PoE
-FastEthernet/Gigabit
-Quality of Service(QoS)
Distribution Layer Switch Features:
-Layer 3 Support
-High Forwarding Rate
-Link Aggregation
-Redundant Components
-Security Policies
-Gigabit/10 Gigabit
-QoS
Core Layer Switch Features:
-Layer 3 Support
-Very High Forwarding Rate
-Link Aggregation
-Redundant Components
-Gigabit/10 Gigabit
-QoS


Switches – Small and Medium Business (SMB)
Cisco has seven switch product lines. Each product line offers different characteristics and features, allowing you to
find the right switch to meet the functional requir ements of your network.
The Cisco switch product lines are:
Catalyst Express 500
Catalyst 2960
Catalyst 3560
Catalyst 3750
Catalyst 4500
Catalyst 4900
Catalyst 6500

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Chapter 2
Switch Concepts and Configuration Part I

Ethernet Communications
-Unicast: one-to-one
-Broadcast: one-to-all
-Multicast: One-to-many

Ethernet Frame: Minimum 64 bytes, Maximum 1518 bytes
Preamble/SOFD: Synchronize to medium.
Destination Address: MAC Address of destination device.
Source Address: MAC address of source device.
Length/Type: Length of frame or protocol type code.
Data: Encapsulated data from OSI Layers 7 to 3.
FCS: Frame Check Sequence.
MAC Address: 12 hexadecimal digits
Broadcast: Indicates a broadcast or multicast frame.
Local: indicates whether the address can be modified loc ally.
OUI Number: Manufacturer of the NIC.
Vendor Number: Unique, vendor assigned number.

Half Duplex (CSMA/CD)
-Unidirectional data flow
-Higher potential for collision
-Hub connectivity
Full Duplex
-Point-to-point only
-Attached to dedicated switched port
-Requires full-duplex support on both ends
-Collision-free
-Collision detect circuit disabled
Switch Port Settings:
AUTO:
Auto-negotiation of duplex mode. The two ports com municate to determine the best mode.
Default for FastEthernet and