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Cisco® Field Manual: Catalyst® Switch Configuration by Steve McQuerry, Dave Hucaby

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5-5. Virtual Interfaces

  • Virtual interfaces exist for configuration where there is no single physical attachment to a broadcast domain.

  • For switches with Layer 2 interfaces, VLANs define broadcast domains.

  • The VLAN interface is a Layer 3 interface for any member of the given VLAN.

  • For switches or routers with Layer 3 interfaces, broadcast domains are defined as bridge groups.

  • To route between bridge groups and other broadcast domains, a bridged virtual interface (BVI) is used as a Layer 3 interface.

  • In some instances, a physical Layer 3 interface can support traffic from multiple VLANs.

  • To provide Layer 3 interfaces for each VLAN on the physical connection, a subinterface is configured as the Layer 3 interface for the members of the VLAN.

Configuring ...

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