Etherchannel Trunking?

Answered Question
Feb 19th, 2010

Just began configuring a WS-CBS3130G-S today and have run into a problem with my port channels- can't get the interface to go into trunk mode.


Has anyone seen this before?



(config)#int po 20

(config-if)#switchport
Command rejected: Not a convertible port.




Any help/advice would be greatly appreciated!

Correct Answer by francisco_1 about 7 years 5 days ago

No. You need to make it a switch port before you can make it a trunk.


config t

int portchannel 1

switchport.


No switchport means that the port is a layer 3 routed port. Trunking will not work on routed port. Also make sure that all ports that are part of the channel also make them a switch port as i describe above.

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Carl Harbeck Fri, 02/19/2010 - 14:19

(config-if)#switchport ?
  access            Set access mode characteristics of the interface
  autostate         Include or exclude this port from vlan link up calculation
  backup       Set backup for the interface
  block        Disable forwarding of unknown uni/multi cast addresses
  host         Set port host
  mode         Set trunking mode of the interface
  nonegotiate  Device will not engage in negotiation protocol on this interface
  priority     Set appliance 802.1p priority
  protected    Configure an interface to be a protected port
  trunk        Set trunking characteristics of the interface
  voice        Voice appliance attributes
 

Reza Sharifi Fri, 02/19/2010 - 14:30

Try this:


Management-Switch(config-if)#switchport mode access

or


Management-Switch(config-if)#switchport mode trunk


and see what happens


Reza

Carl Harbeck Fri, 02/19/2010 - 14:33

#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

(config)#int PO 20

(config-if)#switchport mode trunk

Command rejected: Po20 not a switching port.

(config-if)#switchport mode access

Command rejected: Po20 not a switching port.

config-if)#

Reza Sharifi Fri, 02/19/2010 - 14:41

Do you have IP address configured on the portchannel?


can you post the config?


Reza

Carl Harbeck Fri, 02/19/2010 - 14:44

interface Port-channel20
no switchport
no ip address
no ip route-cache


I need an IP address assigned to trunk?

Correct Answer
francisco_1 Fri, 02/19/2010 - 14:46

No. You need to make it a switch port before you can make it a trunk.


config t

int portchannel 1

switchport.


No switchport means that the port is a layer 3 routed port. Trunking will not work on routed port. Also make sure that all ports that are part of the channel also make them a switch port as i describe above.

Carl Harbeck Fri, 02/19/2010 - 14:50

Won't let me..


(config)#int port-channel 20
(config-if)#switchport
Command rejected: Not a convertible port.

francisco_1 Fri, 02/19/2010 - 14:58

If you aready have a port that's  part of the channel, make them switchport also.


show etherchannel summary - this should list ports under the channel.


Also if you cannot convert the portchannel to switchport, remove it and recreate and make sure before doing that convert all memebers to layer2 by issuing the  switchport command under the interface.

Reza Sharifi Fri, 02/19/2010 - 14:53

Can you also post the config of the physical interface you

added to this portchannel if any?


BTW,  you don't need to have IP I was just asking to make sure you do not have any and I just remember that 3100 switch are layer-2 only

Carl Harbeck Fri, 02/19/2010 - 15:26

So, got it working - thanks for the tips guys.


Here's what I did (guess I started the config in the wrong order):


  1. Made each interface which I wanted to join to the EtherChannel a switchport and switchport trunk.
  2. After doing so, the EtherChannel had no ports assigned because the EC itself was still Layer 3.
  3. Changed portchannel into a switchport / switchport trunk.
  4. Re-added my interfaces back into the portchannel group.
amrelec Fri, 02/19/2010 - 15:28

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