Trunking Cisco ESW-520 8 port and Cisco Catalyst 3560G

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Aug 27th, 2010
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I have a Cisco ESW520 8 port that is connected to a cisco catalyst 3560G.

Our switch management is on VLAN 100 and vlan 1 is the data network.

I have trunked the two switchs and on the interface of the 3560G is as follows:

interface GigabitEthernet0/6

  switchport trunk encapsulation dot1q

switchport trunk native vlan 100

switchport trunk allowed vlan 1,100

switchport mode trunk

ip dhcp snooping trust

On the switch ESW, i have used the smartport macro Switch with native vlan 100 and allowed vlan 1,100 on the gigabit uplink and desktop macro vlan 1 on the other ports.

Now, the native vlan works fine, I can access the ESW switch from the vlan 100 from the 3560G vlan 100.

The problem is that the vlan 1 is not being trunked and I cannot access the vlan 1 at all, from the ESW 520.

I cannot see the issue here.

Thanks for your help,


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datamex Thu, 12/09/2010 - 10:10
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Hey Ashley,

It seems i have a simular problem but than with a cisco router 878 to a ESW 520-8p. I can access the native vlan 1 on the esw switch but the ip address i configured for the vlan 2 ( our voice vlan ) i can't access.

An other location i have 2 cisco catalyst switches 2960 and these are working fine with the router configuration. I can access from the other location the second vlan on the cisco router 878. with the ESW 520-8p connected.

I am wondering if you solved the issue in the time you posted this messages?

best regards,


letsgomets Thu, 12/09/2010 - 14:01
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I am willing to bet the 520 is not forwarding traffic on VLAN1. There is nothing wrong with the 3560 config.

However I personally would never use VLAN 1 for anything because that is the default VLAN for any undefined ports. Additionally I would never use a Native VLAN that has valid host traffic on it. In your case your management network. That is a L2 security risk. The Native VLAN should be exclusive to only trunking information.

I am not familiar at all with the "smartport macro" but on the 520 you need to ensure that the uplink is indeed configured as a trunk and it permitted to forward (tag) VLAN 1 traffic.

Perhaps this link will help. It sounds similar to your problem.


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