while configuraing router for trunking i got this message...

trying to enable truk for vlan 2, with the following commands
Router(config)#int e0.2
Router(config-subif)#ip address 172.16.2.1 255.255.0.0
Router(config-subif)#encapsulation dot1q 2

I got this msg as soon as i entered the ip address:

Configuring IP routing on a LAN subinterface is only allowed if that
subinterface is already configured as part of an IEEE 802.10 or ISL vLAN.

what does this mean?

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Comments

garv221

Configure it a secondary address?

dignity

when you create vlan 1 (native vlan for dot1q ) did you use a sub interface or not
because
802.1Q Configuration on the Router for Cisco IOS Versions Earlier than 12.1(3)T a bit different ... it is important to configure the native VLAN to Interface not as a sub-interface.. this may not be the answer for your questions but just asking..

by the way is this a error massage because i checked web for that there are to many people asking that..
when u command "sh run " can you see your sub interfaces that u created..

Nocturnal

Have you already configured an e0/0.1?

sonagccna

no i did n't as native vlan need not be configured with dot1q

and i configured just the ip address as follows

Router(config)#int e0
Router(config-subif)#ip address 172.16.1.1 255.255.0.0

and the IOS version of router is 11.2

ThanatosKnight

Hi sonagccna ,

you have to use fast ethernet or gigabit interfaces to enable the encapsulation isl o dot1q . Finally , to configure it you have also to follow
the rules related to the configuration concepts (e.g. the concept of native vlan) .

Enjoy

Thanatos

P.S.= Not all cisco routers support the encapsulation isl or dot1q ... At the moment, I only know that you need a 2600 or 1700 at least .

sonagccna

i configured with 2500 series, so i can't check for the exam

as i have only 2500 series routers

but yes i followed the rule - native vlan

nethead

You need to configure the trunking before applying the ip address command, ie.

Router(config)#int e0.2
Router(config-subif)#encapsulation dot1q 2
Router(config-subif)#ip address 172.16.2.1 255.255.0.0

It needs to know its a trunk before you can configure the ip address.

You should be able to do trunking on any router port, so you can do it on 10/half duplex ports.

alastair

sonagccna wrote:

no i did n't as native vlan need not be configured with dot1q

and i configured just the ip address as follows

Router(config)#int e0
Router(config-subif)#ip address 172.16.1.1 255.255.0.0

and the IOS version of router is 11.2

Something odd going on there... using the "int e0" command you should get a prompt like Router(config-if), not -subif.

Maybe that's part of your problem. Did you remove the address from the main interface before adding it to the subinterface?

sonagccna

Did you remove the address from the main interface before adding it to the subinterface?

goodpoint alastair

and nethead encapsulation command itself is not available int ethernet0.1 in router subconfig mode(router 2524)