Ethernet 1/0.1 can't pass Vlan 1 traffic

[rodonohu1]

Hi,

I am having a problem with passing Vlan 1 traffice on an ethernet interface.

I have a 3640 router and had set it up as follows:

The Ethernet1/0 interface set up with a subinterface Eether1/0.1 and set up encapsulation dot1q on this for Vlan 1.

However, once i set this up and connect it to a trunk port on a 2980 switch, no traffic passses onto the switch.

Am i doing something wrong here? It works fine if apply the ip address to the Physical interface Ethernet1/0 but not on the subinterface?? Any ideas?

[globalnettech]

Hello,

can you try:

encapsulation dot1q 1 native

and see if that makes a difference ?

Regards,

GNT

[rodonohu1]

Hi,

I tried that.

The encapsulation defaults to native for Vlan 1. no luck with it.

[sourabhagarwal]

can u paste config of switch port config as trunk and cisco 3640 rtr ethernet config?

[glen.grant]

Please post the 3640 and the config for the 2980 . Make sure the native vlan on the 2980 is set for vlan 1 also and not some other vlan . The 2980 trunk would have to be forced on also , encapsulation dot1q and nonegotiate on the trunk port.

[tdrais]

If you are really using a ethernet interface rather than a fast ethernet it may be same issue I have seen on 2610/2611 routers.

On these routers the native keyword does not appear to work. The solution even though you should not be able to configure it this way is to configure a address on the physical port and that is your native vlan. You can then also configure subinterfaces that have tagged vlans. It is unclear why this works but it may be a option to try.

If you are using fast ethernet then as the above posts indicate there is a issue between the switch and the router.