Cat 3750 Subinterface

jamie.gleeson · ‎06-15-2009

Hello, I am trying to configure a subinterface such as g1/0/1.1 for example but the IOS is indicating "Invalid input detected". Does the 3750 series not support subinterfaces.

The switch model is WS-C3750-48PS-E with IOS version c3750-ipservices-mz.122.46-SE.

The parent interface configuration is as follows:

interface GigabitEthernet1/0/1

no switchport

no ip address

no cdp enable

Any help appreciated.

Jamie

Thotsaphon Lueangwattanaphong · ‎06-15-2009

Jamie,

Excerpt from C3750 configuration guide 12.2(50)SE(The lastest one,I can find).

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Routed Ports

A routed port is a physical port that acts like a port on a router; it does not have to be connected to a router. A routed port is not associated with a particular VLAN, as is an access port. A routed port behaves like a regular router interface, except that it does not support VLAN subinterfaces. Routed ports can be configured with a Layer 3 routing protocol. A routed port is a Layer 3 interface only and does not support Layer 2 protocols, such as DTP and STP.

###################

HTH,

Toshi

sudheesh.pb · ‎06-15-2009

Jamie,

As toshi suggested it will not work, but if your aim is to give another IP address to this interface, you can configure secondry IP address.

glen.grant · ‎06-15-2009

If the idea is to trunk more than 1 vlan then you create your layer 3 SVI and put the ip addresses under that and just trunk the layer 2 vlans across that link

int vlan 2

ip address 192.168.2.254 255.255.255.0

int vlan 3

ip address 192.168.3.254 255.255.255.0

int g1/0/1

switch mode trunk

switch trunk encapsulation dot1q

switchport trunk native vlan 2

switchport trunk allowed vlan 2,3

Alvaro Garcia · ‎06-15-2009

I think that the question is why do you need to configure the subinterface? Is it for InterVLAN Routing?

You can configure that ports as trunk and then create Interface VLANs.

kishan1984 · ‎06-15-2009

3750 switches doesn't support sub-interfaces,create SVI,if you want to make inter-vlan routing.