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802.1q trunking 2611 to 3524

Unanswered Question
Mar 4th, 2004
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I'm trying to set up an 802.1q trunk between the buit-in 10meg ehternet port on a 2611 router and a cat 3524 switch. I am running release 12.2(11)T10 on the router. The subinterfaces will come up but I can not ping any devices on the vlans on the switches.

I know that 802.1q was not supported on the built-in interface till 12.2(2)T but should be with my version.

Are there any special caveats for configuring 802.1q trunking on these interfaces?



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msdonahue Thu, 03/04/2004 - 10:08
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Which feature set are you running? The are 14 feature sets available for 12.2(11)T10 but only 8 support 802.1q trunking.

Anonymous (not verified) Thu, 03/04/2004 - 12:06
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What does your subinterface config look like? Do you mind posting it?

joe.pollere Thu, 03/04/2004 - 13:01
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Here it is:


interface Ethernet0/0

no ip address

no ip unreachables

no ip proxy-arp

duplex full


interface Ethernet0/0.1

encapsulation dot1Q 1 native

ip address

ip helper-address

no ip unreachables


interface Ethernet0/0.2

encapsulation dot1Q 2

ip address

ip helper-address

ip helper-address

no ip unreachables


interface FastEthernet0/24

description 2611 router E0/0

duplex full

speed 10

switchport trunk encapsulation dot1q

switchport mode trunk

switchport voice vlan 2

Anonymous (not verified) Mon, 03/08/2004 - 11:50
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Your config looks good. That's exactly how I have mine configured and it works. I'm stumped. Sorry!

joe.pollere Mon, 03/08/2004 - 13:20
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ok thanks...at least we know that the config is correct.

Appreciate your help.

milan.kulik Mon, 03/08/2004 - 23:46
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  • Red, 2250 points or more


I think this is the right moment to use a protocol analyzer.

Configure a SPAN (mirror) port on the switch mirroring the trunk traffic.

Connect a data analyzer (a PC running Ethereal freeware, e.g.) to it.

Try to Ping to/from the router and capture the ICMP frames.

You should see if your router sends/replies the correct frames.




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