Configuring an Etherchannel (with LACP) between JunOS and Cisco IOS

Juniper JunOS

Firstly create the aggregated interface:

edit chassis
set aggregated-devices ethernet device-count 2

top
edit interfaces
set ae0 aggregated-ether-options

and define the LACP interval period (i.e. the rate at which the device will send / receive LACP protocol messages):

set aex aggregated-ether-options lacp periodic fast

By default the 'lacp periodic fast' sets the transmission rate to 1 second.

Note: It's important that the rate is matched on the other end as well.

We'll now associate our interfaces with the aggregated link we've just configured:

edit interfaces
edit ge-0/0/1
set ether-options 802.3ad ae0
exit
edit ge-0/0/2
set ether-options 802.3ad ae0

Cisco IOS

conf t
int range gi1/0/1-2
channel-protocol lacp
channel-group 1 mode active
lacp rate fast
no shut

int po1
description etherchannel