Customer requires assistance on configuring Active-Active MC-LAG between a pair of EX4650 switches managed by MIST.

Customer followed our document and was able to bring up the MC-LAG peers with active-standby mode. However, ICCP peer showed down in active-active mode.

>>> Customer is using IRB interfaces as ICCP peers.

>>> It's necessary to bind static ARP of each other's IRB addresses on each ICCP peer otherwise ICCP peer remains down.

>>> ICCP went up after adding static ARP entries on each other's IRB interfaces.

(Updated on 22nd of August)
Other check points include:
1. ICCP VLAN, used to establish ICCP peering, should not be allowed on downstream MC-AE interfaces otherwise ICCP cannot be established. Refer to KB KB72787 [juniper.net] for more details.

2. "backup-peer-ip" needs to be configured correctly.

3. On Junos versions later, static ARP on each other's IRB is not required. Refer to the document below, section "VRRP Active-Standby Support" for more details.
https://www.juniper.net/documentation/us/en/software/junos/mc-lag/topics/concept/best-practices-usage-notes.html