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Community Member


We have 2 core switches and a lot of access switches with each access switches connected to each of the core.

My question is as floows:

1. There are 2 gbic ports between the 2 core switches. Is it possible for me to form an etherchannel between the 2 of them


1/1 and 2/1 core a to

1/1 and 2/1 core b

how can i form an ethechannel between them.


each access switch is connected to the core switch

4/1 core a

4/1 core b.

is it possible to form an etherchannel between them and how do i go about doing this.

Thanks for your help

Cisco Employee

Re: EtherChannel

Yes you can have ether-channel members from different modules in most switches? What kind of switches do you have?

Community Member

Re: EtherChannel


They are C6509, so can I do

Thr trunk ports are already set for mode on

set port channel 1/1,2/1 on Core A and

set port channel 1/1,2/1 on Core B

Please note that 1/1 on Core A is connected to 1/1 on Core B and 2/1 on Core A is connected to 2/1 on Core B like this

1/1 ---------------------1/1

2/1 --------------------- 2/1

So please how will they form an etherchannel?


Cisco Employee

Re: EtherChannel

It will work on 6500 for sure. Do you have any issues with channel not coming up? Also best practice is to use "desirable" mode rather than "on"


Re: EtherChannel

First you need to reform the channel groups to span cards. By default they are four adjacent ports on the same card. here is part the doc I wrote on how we did it between three 65xxs, two gig ports between each.

If you want to check a channel the intuitive command doesn’t tell you much.

Michaels_CAT1> (enable) sho channel

Channel Id Ports

----------- -----------------------------------------------

808 4/16,6/16

872 4/15,6/15

All this tells you is that two channels have been defined and what ports they should be on. To see their status try…

Michaels_CAT1> (enable) sho port channel

Port Status Channel Admin Ch

Mode Group Id

----- ---------- -------------------- ----- -----

4/16 connected on 335 808

6/16 connected on 335 808

----- ---------- -------------------- ----- -----

4/15 connected on 437 872

6/15 connected on 437 872

----- ---------- -------------------- ----- -----

Port Device-ID Port-ID Platform

----- ------------------------------- ------------------------- ----------------

4/16 SCA050703R3(Michaels CAT2) 4/1 WS-C6509

6/16 SCA050703R3(Michaels CAT2) 5/1 WS-C6509

----- ------------------------------- ------------------------- ----------------

4/15 TBM06197161(Michaels CAT3) 3/1 WS-C6513

6/15 TBM06197161(Michaels CAT3) 4/1 WS-C6513

----- ------------------------------- ------------------------- ----------------

Michaels_CAT1> (enable)

Here you can see that there are two channels. Each has two ports and both ports in each are active. Then it identifies the switch and port at the other end of each link in the channels. If you disconnected 6/15 in CAT1 it would show disconnected and you would not see the remote device information for that link. However, channel 872 would still be up using one link, 4/15 and you would see that remote device info.

To set up a channel two steps are necessary. Define the channel group you want. Then set the ports to a channel mode that is compatible with the mode set on the ports at the other end. We set ours on to bypass any negotiation delay. By default the switch has channel groups already defined in groups of four ports across each card. You can see the groups like this.

Michaels_CAT1> (enable) sho channel group

Admin Group Ports

----------- -----------------------------------------------

167 7/1-4

168 7/5-8

169 4/1-4

170 4/5-8

171 4/9-12

172 4/13-14 < This group is 2 ports because 2 were removed for other groups

173 5/1-4

174 5/5-8


330 6/13-14 < Same here

335 4/16,6/16 < This group was manually created to span 2 cards

336 9/1-4

337 9/5-8


437 4/15,6/15 < Same here

These are global statements that define the channel groups. Most of these are defaults. The Admin group number is added automatically when creating a new group.

#port channel

set port channel 6/9-11 165

set port channel 7/1-4 167


set port channel 4/13-14 172 < This one changed automatically

set port channel 5/1-4 173


set port channel 6/13-14 330 < and this one

set port channel 4/16,6/16 335 < When the new groups were defined here

set port channel 9/1-4 336


set port channel 5/15 436

set port channel 4/15,6/15 437 < and here

These commands set the ports to skip negotiation and go directly into channel mode. It brings the link up faster and is required if the other side is set to on. These statements do not bind 4/15 and 16 in any way. Its just how the system displays sequential ports with the same settings.


#module 4 : 16-port 1000BaseSX Ethernet

set port channel 4/15-16 mode on

#module 6 : 16-port 1000BaseSX Ethernet

set port channel 6/15-16 mode on

A channel is not necessarily a trunk, you could channel an individual VLAN. To see what kind of channel it is look at the ports that make up the channel/s. Below you see that the ports in these channels are set as trunks.

Michaels_CAT1> (enable) sho port

Port Name Status Vlan Duplex Speed Type

----- ------------------ ---------- ---------- ------ ----- ------------

1/1 GIGSniffer notconnect 1 full 1000 No GBIC


4/14 ecubb01 connected 51 full 1000 1000BaseSX

4/15 ISL etherchannel connected trunk full 1000 1000BaseSX

4/16 ISL etherchannel connected trunk full 1000 1000BaseSX

5/1 notconnect 60 full 1000 1000BaseSX


6/14 notconnect 1 full 1000 1000BaseSX

6/15 ISL etherchannel connected trunk full 1000 1000BaseSX

6/16 ISL etherchannel connected trunk full 1000 1000BaseSX

7/1 A Wing Front connected trunk full 1000 1000-LX/LH

7/2 A Wing Rear connected trunk full 1000 1000-LX/LH

To bypass negotiation our trunks are set on like the channel ports

#module 4 : 16-port 1000BaseSX Ethernet

set trunk 4/15 on isl

set trunk 4/16 on isl

#module 6 : 16-port 1000BaseSX Ethernet

set trunk 6/15 on isl

set trunk 6/16 on isl

Community Member

Re: EtherChannel

Hi there

I notice right from the beginning of the conversation that the guy needed to form EtherChannel between port 1/1 and 2/1 on the same switch to the other switch on ports 1/1 and 2/1. I thought that to carry out EtherChannel, you need to have consecutive ports for example 1/1-2 or 2/1-2. Have you any experience in configuring EtherChannel on non-consecutive ports? If it is working for you at the moment, can you tell me what version of IOS, CatIOS that you're using? I'm currently running two Cat4006 with CatIOS ver 7.4.3. Thanks in advance for your answer. Please email me on

Cisco Employee

Re: EtherChannel

The restriction of consecutive ports was only in older CAT OS in CAT5k switches and XLs. In a CAT6500 and 4006, the channel members need not be consecutive and can be from different modules

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