DynamicMAC addresses learned in one VLAN of a private VLAN are replicated in
theassociated VLANs. For example, a MAC address learned in a secondary VLAN is
replicatedin the primary VLAN. When the original dynamic MAC address is deleted
oraged out, thereplicated addresses are removed from the MAC address table.
Note
ConfigureLayer 3VLAN interfaces (SVIs) onlyfor primaryVLANs.
Information About Private VLANs

Private VLAN Domains

Theprivate VLAN featureaddresses two problems that service providers facewhen using VLANs:
Theswitch supports up to 1005 active VLANs. If a service provider assigns one VLAN per customer,
thislimits the numbers of customers the service provider can support.
Toenable IP routing, each VLAN is assigned a subnet address space or a block of addresses, which can
resultin wasting the unused IP addresses, and cause IP address management problems.
Usingprivate VLANsaddresses the scalabilityproblem and providesIP addressmanagement benefits for
serviceproviders and Layer 2 security for customers.Private VLANs partition a regular VLAN domain into
subdomains.A subdomain is represented by a pair of VLANs: a primary VLAN and a secondary VLAN. A
Catalyst 2960-XR Switch VLAN Configuration Guide, Cisco IOS Release 15.0(2)EX1
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Configuring Private VLANs
Information About Private VLANs