1.
Switching in an
Enterprise Network
Introducing Routing and Switching in the Enterprise –
Chapter 3
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2.
Objectives
 Compare the types of switches used in an enterprise
network.
 Explain how Spanning Tree Protocol prevents
switching loops.
 Describe and configure VLANs on a Cisco switch.
 Describe and configure trunking and Inter-VLAN
routing.
 Maintain VLANs in an enterprise network.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2

3.
Compare the Types of Switches Used in an
Enterprise Network
 Switching and network segmentation
 Content addressable memory (CAM)
 Virtual circuits
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4.
Compare the Types of Switches Used in an
Enterprise Network
 Hardware-based Layer 2 switching
 Software-based Layer-3 (multilayer) switching
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5.
Compare the Types of Switches Used in an
Enterprise Network
 Store and forward switching
 Cut-through switching
Fast-forward
Fragment-free
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6.
Compare the Types of Switches Used in an
Enterprise Network
 Switch physical security
 Switch access security
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7.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 Redundancy in network equipment
 Redundant network links
 Dangers of switching loops
 Broadcast storms
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8.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 Create a loop-free logical topology
 Potential loop detection and port blocking
 Redundancy without switching loops
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9.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 Determining a root bridge
 Bridge ID (BID)
 Root ports, designated ports, and blocked ports
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10.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 STP recalculations
 Minimizing downtime
PortFast
UplinkFast
BackboneFast
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11.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 Spanning-tree verification commands
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12.
Explain How Spanning Tree Protocol Prevents
Switching Loops
 Rapid Spanning Tree Protocol
 Discarding
 Active topology
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13.
Describe and Configure VLANs on a Cisco
Switch
 Virtual LANs
 Logical networks
 Broadcast control
 Transparent to end-users
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14.
Describe and Configure VLANs on a Cisco
Switch
 VLAN functions
 VLAN membership
Static
Dynamic
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15.
Describe and Configure VLANs on a Cisco
Switch
 VLAN 1: management VLAN
 VLAN numbers and names
 Port assignment
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16.
Describe and Configure VLANs on a Cisco
Switch
 VLAN verification commands
 Deleting a VLAN
 Removing a port from a VLAN
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17.
Describe and Configure VLANs on a Cisco
Switch
 VLAN ID
 Frame tagging: IEEE 802.1Q
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18.
Describe and Configure Trunking and Inter-
VLAN Routing
• Trunk port characteristics
Point-to-point link
Carry multiple-VLAN traffic over single link
• Support for frame tagging
• Trunk modes
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19.
Describe and Configure Trunking and Inter-
VLAN Routing
 Extending VLANs across switches
 Configuring a native VLAN
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20.
Describe and Configure Trunking and Inter-
VLAN Routing
 Connectivity between different VLANs
 Subinterfaces
 Router-on-a-stick
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 20

21.
Maintain VLAN Structure on an Enterprise
Network
 VLAN Trunking Protocol (VTP) purpose and goals
 Management domain
 VTP modes: server, client, transparent
 VLAN database
 Configuration revision number
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22.
Maintain VLAN Structure on an Enterprise
Network
 VTP messages
Summary advertisements
Subset advertisements
Advertisement requests
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23.
Maintain VLAN Structure on an Enterprise
Network
 Configuring VTP
 Verifying VTP configuration
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24.
Maintain VLAN Structure on an Enterprise
Network
 VLANs and IP phones
 VLANs and wireless security
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25.
Maintain VLAN Structure on an Enterprise
Network
 VLAN best practices
 VLAN security
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 25

26.
Summary
 Switches forward traffic using store and forward or cut-through
techniques
 Basic security features should be applied to switches
 A VLAN is a way to group hosts on the same logical network even
though they may be physically separated
 Frame tagging allows a switch to identify the source VLAN of an
Ethernet frame.
 A Layer 3 device is needed to move traffic between different
VLANs.
 Subinterfaces allow router interfaces to support multiple VLANs.
 VLAN Trunking Protocol provides centralized control, distribution
and maintenance of VLANs.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 26

27.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 27