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Etherchannel and trunk on two Cat6506 ports to VMware server

I am working on setting up vlan trunks as well as LACP bundles on two Cat 6506 ports (running 8.3 CatOS) to connect to a dual nic on a VMware server.

The trunk works but LACP doesn't seem to be running across the link. I have followed the Cisco docs for configuring this but it still doesn't seem to be working.

I have been able to successfully set this up for a different server on a single VLAN on the same module.

When I do a 'show port (port number)' on the channel that works I see the Partner Oper Sys ID as 'number:mac address', with the mac address of the server. When I do a 'show port' on the channel that doesn't seem to be set up, I get all zeros for the Partner Oper Sys ID.

Any help is greatly appreciated.




Re: Etherchannel and trunk on two Cat6506 ports to VMware server

Can you provide show lacp-channel group , show lacp-channel and show port x/x (ports that are member of the lacp-channel? Also, is the lacp-channel between the two 6506? or between the dual NIC of the VMWare and the two 6506?

If it's the latter, then you cannot form a channel from a single device that connects to two different devices devices, for example switch A is dual home to switch B and C via port 1/1 and 1/2 on switch A, you cannot do port channel on port 1/1-2 on switch A. Not sure this is what you have but just want to throw this in.

If not, and you are channeling between the two 6506, make sure the ports are identical in all ways. That includes port capabilities and the way each port is configured.

Community Member

Re: Etherchannel and trunk on two Cat6506 ports to VMware server


Thank you for your response!

I am attaching the outputs you requested. To clarify a little, I have two ports on a 6506 that are connecting to two interfaces of a dual-port NIC of a server. The two Catalyst ports are in the same module on this 6506. I hope that makes sense.

Thanks again for your help,


Re: Etherchannel and trunk on two Cat6506 ports to VMware server

active lacp LACP mode that places a port into an active negotiating state in which the port initiates negotiations with other ports by sending LACP packets.

It seems the VMWare might not be negotiating LACP, have you tried "ON" Mode?

Community Member

Re: Etherchannel and trunk on two Cat6506 ports to VMware server

Thank you for the info. I changed the mode to ON and the channel came up!

At the moment, this change doesn't seem to make any difference, for better or worse, to the vmware server. My server guys are talking about making a change concerning frame distribution. They would like the switch to distribute (load-balance) by destination IP. Here is the command: set port channel all distribution ip destination

This is a global command. Does this make sense, or could this cause problems? I have 3 other etherchannels setup, but they are all new connections, not currently in production.

Any idea?


Re: Etherchannel and trunk on two Cat6506 ports to VMware server

An EtherChannel balances the traffic load across the links in an EtherChannel by reducing part of the binary pattern formed from the addresses in the frame to a numerical value that selects one of the links in the channel.

EtherChannel load balancing can use MAC addresses or IP addresses. EtherChannel load balancing can use either source or destination or both source and destination addresses or ports. The selected mode applies to all EtherChannels configured on the switch.

Use the option that provides the balance criteria with the greatest variety in your configuration. For example, if the traffic on an EtherChannel is going only to a single MAC address and you use the destination MAC address as the basis of EtherChannel load balancing, the EtherChannel always chooses the same link in the EtherChannel; using source addresses or IP addresses might result in better load balancing.

The load-balancing policy (frame distribution) can be based on a MAC address (Layer 2), an IP address (Layer 3), or a port number (Layer 4). These policies can be activated, respectively, by the mac, ip and session keywords. The load balancing can be based solely on the source address (source keyword), destination address (destination keyword), or both source and destination addresses (both keyword).

Should not cause a problem setting the frame distribution. Frame disttibution based on source-destination ip address or mac-address should give you a better chance that the packets will be distribute to both port as explained by the load-balancing above.

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