9800CL: Port-Channel Gi1 and Gi2 for WMI ?

[NIRO-7]

Hello,

I am currently deploying a cluster of 2 9800CL controllers, and the customer asks me bundle Gi1 and Gi2 in a Port-Channel to use it as the WMI.

I didn't find anything talking about that case in the Configuration Guide, the HA SSO Deployment guide and the best practices aswell.

I tried to set up this architecture in my lab, but this is what happened when I tried :

(config-if)#switchport mode trunk
Command rejected: Po1 is not a switching port.

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

I don't know if there is a need to configure something on the VMWare side, or if it's possible at all.

Does anyone had this case already ?

Thank for reading me.

Nicolas

[marce1000]

   - That isn't supported , you need to stick to the native HA SSO  setup for the two 9800CL controller which is supported , 

 M.

[NIRO-7]

Thanks Marce for the reply, that's what I thought.

It is a case of Multi Chassis LAG, right ?

[marce1000]

            >....It is a case of Multi Chassis LAG, right ?
                          Right , 

 M.

[Rich R · Accepted solution]

Bundling interfaces on 9800-CL is completely pointless - it's a virtual port!
If you want physical port redundancy then that should be done on the ports between your ESX server and the physical switch(es) - not on the VM.

The reason you got that error is because G1 and G2 have specific functions on CL.  G1 is the management interface - like Gig0 on a physical 9800 - it's not intended to be used for customer traffic at all - purely for WLC out of band management access.  G2 is for WMI use and supports trunk and VLANs.  So in the same way you could not form an etherchannel with Gi0 and Te0/0/0 on a 9800-80, you cannot form an etherchannel from G1 and G2 on 9800-CL.

Refer https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9800-cl-wireless-controller-cloud/nb-06-cat9800-cl-wirel-cloud-dep-guide-cte-en.html

"By default, the 9800-CL comes with three network interfaces. Below is an example of interface mapping:

●     GigabitEthernet1 à Device management interface: Map it to the out-of-band management network. This is the equivalent of the service port on the physical appliance.

●     GigabitEthernet2 à Wireless management interface: Map it to the network to reach APs and services. Usually this interface is a trunk to carry multiple VLANs.

●     GigabitEthernet3 à High Availability interface: Map it to a separate network for peer-to-peer communication for HA SSO. This is the equivalent of the RP port. This port is not needed if HA SSO is not going to be configured.

Note:      Do not connect two interfaces to a single network, as that may cause network loops. When a trunk port is used, you must either prune VLANs from vCenter or have the GigabitEthernet interfaces in a different vSwitch."

[NIRO-7]

Hello Richard,

Thanks for the very complete answer.

Indeed, that was my opinion, that bundling virtual interface is useless, but even after telling that to the customer, he insisted about that. Also, as a junior I have a lack of assurance to tell him to follow my advices. 

I knew about the Gi1 being SP, Gi2 WMI and Gi3 RP, but even after telling him that, he insisted, so I wanted to be sure.

Thanks again for taking the time to elaborate a complete and sourced answer.

Have a good day