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  • Layer 3 subinterface (Cisco)

    Design & Configure

    Layer 3 subinterface (Cisco)

    Technology: Network
    Area: Configuration General
    Vendor: Cisco
    Software: 12.X, 15.X
    Platform: ISR Routers, ASR Routers

    Subinterfaces divide the parent interface into two or more virtual interfaces on which you can assign unique Layer 3 parameters such as IP addresses and dynamic routing protocols parameters. The IP address for each subinterface should be in a different subnet from any other subinterface on the parent interface (if you are not using VRF-Lite feature).

    Switch# configure terminal
    switch(config)# interface ethernet 2/1.1
    switch(config-if)# ip address
    switch(config-if)# encapsulation dot1Q 33

    Because subinterfaces work always on trunk links, there is a necessity of encapsulation definition. The encapsulation command defines the VLAN tag (VLAN number) which will be using by this subinterface.


    Author: Marcin Bialy