EtherChannel with VMware ESXi 4.1

EtherChannel allows multiple physical Ethernet links to combine into one logical channel, which allows the links in the channel to share traffic load, as well as redundancy in the event that one or more links in the channel fail.

When setting an EtherChannel mode in a Cisco switch, your choices are ‘on’, ‘off’, ‘active’, ‘passive’, ‘desirable’ or ‘auto’. Each mode setting forces a particular negotiation protocol and behaviour as such:

Mode	Negotiation	Operation
on	None	Enables EtherChannel, does not negotiate
off	None	Disables EtherChannel
active	LACP	Initiates negotiation to enable EtherChannel
passive	LACP	Responds to received negotiation requests
desirable	PAgP	Initiates negotiation to enable EtherChannel
auto	PAgP	Responds to received negotiation requests

LACP is IEEE, PAGP is Cisco-proprietary. If it is ON then it doesn't negotiate either protocol.   So if you have a non-Cisco switch and you want to run etherchannel from it, you have to either run LACP or set it to "on".

ESX does not support PAgP or LACP and therefore you need to set Etherchannel to the mode "on".

The following is a ESX Server and Cisco switch sample topology and configuration.

Note:  When stacked the Cisco 3750 switches act as one logical switch.  Each NIC port should be redundantly connected to each switch to support switch fail over.



Cisco 3750 Stacked Switches



interface Port-channel 1

 description Link aggregate for “ESX Server"

 switchport trunk encapsulation dot1q

 switchport mode trunk

switchport trunk nonegotiate
!
interface GigabitEthernet 1/1/1
switchport trunk encapsulation dot1q

switchport mode trunk

switchport trunk nonegotiate

channel-group 1 mode on

!
interface GigabitEthernet 2/1/1
switchport trunk encapsulation dot1q

switchport mode trunk

switchport trunk nonegotiate

channel-group 1 mode on

!

To verify a switches current load balancing mechanism, Run the following command

Switch# show etherchannel load-balance

EtherChannel Load-Balancing Configuration:

src-dst-ip

 To configured load-balancing algorithm, the following commands in global configuration mode:

port-channel load-balance src-dst-ip

 To configured load-balancing in the vSwitch see the below:

vSwitch Configuration

In the above example the EtherChanel has been configured as trunk port.  This allows for multiple VLANs to be trunked to the vSwitch.