Hi Mir
I have below example which worked for me.
Cisco Config
interface Port-channel1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1
switchport mode trunk
!
interface FastEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1
switchport mode trunk
channel-group 1 mode passive
!
interface FastEthernet1/0/2
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1
switchport mode trunk
channel-group 1 mode passive
Extreme B5 Config
set port lacp port ge.1.1-2 enable
set vlan egress 1 ge.1.1-2;lag.0.1 tagged
set lacp singleportlag enable
Regards,
Francois