Home > Articles > Cisco > CCNP Routing and Switching

  • Print
  • + Share This
This chapter is from the book

This chapter is from the book

Inter-VLAN Communication on a Multilayer Switch Through a Switch Virtual Interface

Rather than using an external router to provide inter-VLAN communication, a multilayer switch can perform the same task through the use of a switched virtual interface (SVI).

Removing L2 Switchport Capability of a Switch Port

3750Switch(config)#interface fastethernet 0/1

Moves to interface configuration mode.

3750Switch(config-if)#no switchport

Creates a Layer 3 port on the switch.

NOTE: The no switchport command can be used on physical ports only on a Layer 3–capable switch.

Configuring SVI Autostate

3750Switch(config)#interface fastethernet 0/1

Moves to interface configuration mode.

3750Switch(config-if)#switchport auto-state exclude

Excludes the access port/trunk in defining the status of an SVI as up or down.

NOTE: This command is commonly used for ports that are used for monitoring, for example, so that a monitoring port does not cause the SVI to remain "up" when no other ports are active in the VLAN.

Configuring a Layer 3 EtherChannel

Switch(config)#interface port-channel 1

Creates a virtual Layer 2 interface.

Switch(config-if)#no switchport

Changes interface to Layer 3 to enable the use of the IP address command.

Switch(config-if)#ip address 172.32.52.10 255.255.255.0

Assigns an IP address to the Layer 3 port-channel interface.

Switch(config)#interface range fastethernet 5/4 - 5

Moves to interface range configuration mode.

Switch(config-if-range)#no switchport

Creates Layer 3 ports on a switch.

Switch(config-if-range)#channel-protocol pagp

Configures port aggregation protocol.

Switch(config-if-range)#channel-group 1 mode desirable

Assigns the physical interfaces in the range to the EtherChannel group.

Configuring Inter-VLAN Communication

3550Switch(config)#interface vlan 1

Creates a virtual interface for VLAN 1 and enters interface configuration mode.

3550Switch(config-if)#ip address 172.16.1.1 255.255.255.0

Assigns IP address and netmask.

3550Switch(config-if)#no shutdown

Enables the interface.

3550Switch(config)#interface vlan 10

Creates a virtual interface for VLAN 10 and enters interface configuration mode.

3550Switch(config-if)#ip address 172.16.10.1 255.255.255.0

Assigns IP address and netmask.

3550Switch(config-if)#no shutdown

Enables the interface.

3550Switch(config)#interface vlan 20

Creates a virtual interface for VLAN 20 and enters interface configuration mode.

3550Switch(config-if)#ip address 172.16.20.1 255.255.255.0

Assigns IP address and netmask.

3550Switch(config-if)#no shutdown

Enables the interface.

3550Switch(config-if)#exit

Returns to global configuration mode.

3550Switch(config)#ip routing

Enables routing on the switch.

  • + Share This
  • 🔖 Save To Your Account