Catalyst 6509 and 3560G

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Sep 11th, 2006
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Hi,


I want to extend the number of ports available in my network and have just purchased a Cisco 3560G. We have a Cisco 6509 running in Hybrid mode. The VTP mode on the 6509 is Transparent as we have created the VLANs and port assignments manually.

I want to add the new switch and have it hanging of port 6/8 on the Catalyst 6509.

Am I right if I set 6/8 to trunk with Gi0/1? I was ging to do the following in order to communicate between the two switches.


Set port 6/8 to trunking mode dot1q.

Create VLAN 150 and 151 on the 3560G. Add ports to each of the VLANS.


My confusion is this... if the trunk port is on one of the VLANs then the other VLAN will not be able to communicate over it. i.e. if I add the trunk into VLAN 151 then ports in VLAN 150 will not be able to send traffic over it.


What is the ideal way to set this up?


Thanks


Gavin

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Edison Ortiz Mon, 09/11/2006 - 11:00
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Gavin,


The trunk will forward all the common VLANs between the 2 switches. If you configured VLAN150 and VLAN151 manually on both switches, those VLANs will be included in the trunk along with the default VLAN1.


The ideal setup would be going with VTP Server/Client model.


----


Please rate helpful posts.


Thanks


glen.grant Mon, 09/11/2006 - 11:31
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Just setup both sides as "desirable dot1q" and the trunk will be created and will carry all vlans . If you want you can manually prune off any vlans on the trunk that you don't want allowed across the trunk .

gavin.mckee Mon, 09/11/2006 - 12:10
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If I wanted to create an ether channel between the two switches, can I set the Etherchannel to dot1q trunk?


Gavin

Edison Ortiz Mon, 09/11/2006 - 12:13
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You sure can.

sundar.palaniappan Mon, 09/11/2006 - 12:14
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Gavin,


Yes, you can.


All your trunk configuration needs to be configured under the port channel interface.


HTH


Sundar

gavin.mckee Mon, 09/11/2006 - 12:21
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Sorry about all these questions but....


if the native VLAN on the Catalyst is not VLAN 1 say VLAN150 how will his impact on my trunk.


Do I have to make any special changes on the new 3560G?

sundar.palaniappan Mon, 09/11/2006 - 12:42
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Set the native vlan to be the same on both ends. Mismatched native VLANs can create problems even if trunk connects.


802.1q doesn't tag native vlan frames. As such, anytime an untagged frame arrives the switch assumes that it belongs to that vlan. Let's say if the native vlan is set to 150 on one switch and the 2nd switch that receives an untagged ARP frame will assume the traffic came in on vlan 1 (default) and if the switch doesn't know the MAC then it would forward it to vlan 1 and trunk ports. As you can see it can create problems if there's mismatched native vlans.


Hope this helps!

Edison Ortiz Mon, 09/11/2006 - 12:42
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You should match the native vlan on both sides.

gavin.mckee Mon, 09/11/2006 - 12:36
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Sundar,


I am also getting a message on the port that I have set trunking on... the message states that....


INCONSISTENT PORT TYPE....


The port is then blocked by STP....


Is this because spaning tree port fast is configured on the other interface?


Gav

sundar.palaniappan Mon, 09/11/2006 - 12:43
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Remove the spanning-tree portfast command from all the concerned ports.

gavin.mckee Mon, 09/11/2006 - 13:16
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thanks guys for all your help... i'll be trying out the config suggestions you have given.


this is a great learning tool


Thanks again


Gavin

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