Configuring IP subinterface on a 3750ce GigE port

[freize]

I cannot configure IP subinterfaces on a GigE port on a 3750ce. The box tells me that the subif already has to be part of a 802.1q trunk.

Is it not possible to configure these interfaces and encapsulate them with an vlan id and transmit the vlans over a 802.1q trunk?

Am I maybe missing some commands on the major interface?

Thanks

[Georg Pauwen]

Hello,

is your main Gigabit interface configured as a trunk as well ? Can you post your configuration ?

Regards,

GP

[freize]

GP,

When I configure the main GE if as a trunk, it is not possible to configure an IP address on the subif.

Here is what i have configured from scratch:

Switch#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)#int gig 1/0/1

Switch(config-if)#no switchport

Switch(config-if)#int gig 1/0/1.100

Switch(config-subif)#ip in

Switch(config-subif)#ip add

Switch(config-subif)#ip address 172.16.5.1 255.255.255.252

I get the following message:

% Configuring IP routing on a LAN subinterface is only allowed if that

subinterface is already configured as part of an IEEE 802.10, IEEE 802.1Q,

or ISL vLAN.

Thanks for your help

pat.

[Dominique Demore]

Hi Pat,

Subinterfaces can't be created for routing on the 3750. The reason you are getting that error is it's looking for "encapsulation [dot1Q | isl | sde] [vlanid]" which doesn't exist on the 3750.

If possible, I would recommend making int g1/0/1 a trunk, and using SVIs to perform your routing.

HTH

-- Dominique