Sub Interfaces on Switches and ASA

[ejdrijin1]

Hi,

I have a Cisco Catalyst 3750X.

I tried to create sub interfaces but it is giving an error. I am assuming that these are not supported on this device.

1. Can someone confirm if they are supported?

2. Are there any switches that support sub interfaces or is it just routers?

3. Does the ASA 5515X support sub interfaces?

Thanks

[mlund]

Hi

Q1 and Q2  There are 2 ways to it, depending on what is supported.either subinterfaces or or vlan interfaces.

For subinterface use this

interface x/y

 no switchport

interface x/y.10

 encapsulation dot1q 10

 ip address 1.1.1.1 and so on

 for vlan interfaces

 interface vla 10

 ip address 1.1.1.1 and so on

interface x/y

switchport (this is the default)

switchport mode trunk

switchport trunk allowed vla 10 (optional)

Q3  I'm not a asa expert, but last time i configured an asa box it was supported on that unit.

/Mikael

[ejdrijin1]

Thanks for the update.

I got the following when I tried the above:

(config)#int GigabitEthernet1/0/41
(config-if)#no switchport
(config-if)#int GigabitEthernet1/0/41.10
^
% Invalid input detected at '^' marker.

[mlund]

Hi

It seem 3750x doesn't support subinterface command, so you need to use the vlan interface approach then.

see the note in this link

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_53_se/configuration/guide/3750xscg/swvlan.html#wp1497016

/Mikael