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s.nasheet
Beginner

Can I mix Layer 2 and layer 3 Etherchannel

HI,

Can one end of the ehterchannel act as  layer 3 and other end act as layer 2 access  port?

int fa0/1

switchport mode access

channel-group 1 mode on

int fa0/2

switchport mode access

channel-group 1 mode on

!

interface Port-channel1

switchport mode access

Layer 3

int port-channel 1

IP adress 10.10.10.1 255.255.255.248

int G0/1

no ip address

channel-group 1 mode on

int G0/2

no ip address

channel-group 1 mode on

7 REPLIES 7
Peter Paluch
Hall of Fame Cisco Employee

Hello,

Yes, you can mix them. If possible, though, do not use the mode on but instead, use LACP using mode active on both ends of the EtherChannel.

Best regards,

Peter

Many thanks Peter.

I will now try that.

Regards

Salman

Hi Peter,

I also thought both end of a etherchannel should have same config (duplex, speed, config, etc). It is interesting if you could configure one end as L3 & other end of the etherchannel config as L2 & bring the etherchannel up.

Salman: Anyway test it & let us know if it works ?

Regards

Rasika

Hi.

I will work but, for example if one end of the port-channel is configured in the broadcast domain 10.10.10.0/49 then the other end of the port-channel that is assigned to vlan x ( vlan 1 in the example you typed in the intial post) must be in the same broadcast domain otherwise traffic will be dropped.

Regards.

Wilson B.

edwardwaithaka
Beginner

Hi

Did you ever test this case? I need to do L3 etherchannel on ASR to L2 etherchannel on 2960X without using subinterfaces on router.

Yes it is possible. I have done this between ASR1001 and C3850 Switches. 

julian.bendix
Participant

Hi,

yes of course this is possible.
It is the exact same as if you wouldn't have a port-channel.

 

I am just wondering what your use case is to attach an access port to a Routed Port.
Do you have a physical area that just needs one vlan?
Otherwise you will need a trunk configured on the switchport side,
and subinterfaces with vlan-tagging configured on the routed port side.

Also as already mentioned,
your port channel will work fine, but with the current configuration it will be a static port channel (mode on).
If you use "mode active" it will utilize LACP a channel-protocol.
Which can save you if misconfiguration or miscabling occoured.
So using LACP (mode active) is always recommendable.

Best regards and have a nice day,
Julian

P.S. please mark the resolution or helpful answers if applicable.