VLANs and Trunking
See the following sections for configuration information about these topics:
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6-1: VLAN Configuration: Describes the method for configuring, creating, and con-
figuring VLANs on a switch
6-2: VLAN Port Assignments: Explains how to assign a port to a VLAN using static
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or dynamic methods
6-3: Trunking: Covers the method for extending a VLAN beyond the boundaries of
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a single switch through tagging mechanisms
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6-4: VLAN Trunking Protocol: Describes the Cisco proprietary protocol for main-
taining a forwarding path between switches that are trunking and how to prune for
unused VLANs
6-5: Private VLANs: Explains the feature that allows for more granular traffic control
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within the VLAN using the private VLAN structure
6-1: VLAN Configuration
VLANs are broadcast domains defined within switches to enable control of broad-
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cast, multicast, unicast, and unknown unicast within a Layer 2 device.
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VLANs are defined on a switch in an internal database known as the VLAN
Trunking Protocol (VTP) database. After a VLAN has been created, ports are
assigned to the VLAN.
VLANs are assigned numbers for identification within and between switches. Cisco
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switches have two ranges of VLANs, the normal range and extended range.
VLANs have a variety of configurable parameters, including name, type, and state.
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Several VLANs are reserved, and some can be used for internal purposes within the
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switch.
Chapter 6