Connect IE3000 to 3560G trunk

Unanswered Question
Sep 15th, 2008


I have a Catalyst 3560G with port configured as

switchport trunk encapsulation dot1q

switchport mode trunk.

I have the new IE3000 and want to configure the gigabit ports to connect to the 3560G trunk.The ie3000 doco says the commands for a dot1q trunk port is..

switchport mode dynamic desirable

Are these commands sufffient for the two switches to communicate and use vtp?



I have this problem too.
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Mark Yeates Mon, 09/15/2008 - 17:07


You could go either way with your configuration. On your 3560 switch you have the trunking hard coded on the interface. On the IE3000 you have trunking dynamically negotiated using DTP. I would recommend hard coding your trunk settings on the IE3000 side by using "switchport mode trunk" command instead of "switchport mode dynamic desirable". I don't think you will need to specify encapsulation since it only supports dot1q. You shouldn't have any problems using VTP.



glen.grant Mon, 09/15/2008 - 17:16

You have to have both sides the same either "dynamic desirable " or you have to force them on "switchport mode trunk" . Dynamic desirable lets the switches negotiate the trunk and make sure parameters match. Either way will work , some people like to let the switch negotiate others like to force the trunk on .

noeldrose Mon, 09/15/2008 - 17:28

Thanks to those who have responded.

I intend to link several ie3000 in a daisy chain where the first is linked to the 3560 and then each ie3000 has two interfaces defined as trunks. These interfaces link to the next. I would prefer the hard coded option. So I assume I should set all the ie3000 trunks to..

switchport mode trunk



glen.grant Tue, 09/16/2008 - 03:57

That is correct , also make sure your native vlans match if using something other than vlan 1 which is good practice.

noeldrose Tue, 09/16/2008 - 12:28

you may have guessed by now that I'm a bit new to this.

From what I've read I think the native vlan setting is in case the trucking stops the packets in the native vlan are still forwarded. In this lan segment I'm building I have two ctitical vlans. should I set the native to the most critical?

Mark Yeates Tue, 09/16/2008 - 14:41


Either VLAN would be fine. Most recommend changing the native VLAN to something other than 1 for security reasons.



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